FCC ID: ZMOMG661LA LTE Module

MG661-EU/LA Hardware Guide V1.0 Disclaimer Customers must design and develop their products referring to the information provided in the document. The Company shall not be liable for any damage caused by failure to comply with relevant operation or specifications or rules. Due to product version upgrade or other reasons, the Company reserves the right to modify any information in this document at any time without prior notice and any responsibility. Unless otherwise agreed, all statements, information and suggestions in this document do not constitute any express or implied guarantee. Copyright Notice Copyright 2023 Fibocom Wireless Inc. All rights reserved. Unless specially authorized by the Company, the recipient of the documents shall keep the documents and information received confidential, and shall not use them for any purpose other than the implementation and development of this project. Without the written permission of the Company, no unit or individual shall extract or copy part or all of the contents of this document without authorization, or transmit them in any form. The Company has the right to investigate legal liabilities for any offense and tort in connection with violation of confidentiality obligations, or unauthorized use or malicious use of the said documents and information in other illegal forms. Trademark Statement The trademark is registered and owned by Fibocom Wireless Inc. Other trademarks, product names, service names and company names appearing in this document are owned by their respective owners. Contact Information Website: https://www.fibocom.com Address: 10/F-14/F, Block A, Building 6, Shenzhen International Innovation Valley, Dashi First Road, Xili Community, Xili Subdistrict, Nanshan District, Shenzhen Tel: 0755-26733555 Safety Instructions Do not operate wireless communication products in areas where the use of radio is not recommended without proper equipment certification. These areas include environments that may generate radio interference, such as flammable and explosive environments, medical devices, aircraft or any other equipment that may be subject to any form of radio interference. The driver or operator of any vehicle shall not operate wireless communication products while controlling the vehicle. Doing so will reduce the driver's or operator's control and operation of the vehicle, resulting in safety risks. Wireless communication devices do not guarantee effective connection under any circumstances, such as when the (U) SIM card is invalid or the device is in arrears. In an emergency, please use the emergency call function when the device is turned on, and ensure that the device is located in an area with sufficient signal strength. Contents Contents Applicable Model ............................................................................................... 4 Change History .................................................................................................. 5 1 Product Overview ........................................................................................... 6 1.1 Product Introduction ......................................................................................... 6 1.2 Product Specifications ..................................................................................... 6 1.3 Hardware Block Diagram ................................................................................. 8 1.4 Description of Development Board .................................................................. 9 2 Pin Definition ................................................................................................ 10 2.1 Pin Attributes .................................................................................................. 10 2.2 Pin Distribution ............................................................................................... 10 2.3 Pin Details ...................................................................................................... 13 3 Application Interfaces .................................................................................. 24 3.1 Power Interfaces ............................................................................................ 24 3.1.1 Electrical Indicators .................................................................................. 24 3.1.2 Power Input .............................................................................................. 25 3.1.3 Power Output ........................................................................................... 27 3.2 Control Interfaces .......................................................................................... 27 3.2.1 Power-on .................................................................................................. 27 3.2.2 Power-off .................................................................................................. 29 3.2.3 Reset ........................................................................................................ 31 3.2.4 Download ................................................................................................. 33 3.3 Baseband Interface ........................................................................................ 33 3.3.1 USB 2.0 .................................................................................................... 33 3.3.2 UART ....................................................................................................... 35 3.3.3 I2C............................................................................................................ 36 3.3.4 PCM/I2S ................................................................................................... 37 3.3.5 SIM ........................................................................................................... 39 3.3.6 ADC .......................................................................................................... 43 3.3.7 Status Indication ...................................................................................... 44 1 Contents 3.3.8 LCD Interface ........................................................................................... 46 3.3.9 Camera Interface ..................................................................................... 46 3.4 Operating Mode ............................................................................................. 46 3.4.1 Flight Mode .............................................................................................. 47 3.4.2 Sleep Mode .............................................................................................. 48 3.4.3 PSM Mode ............................................................................................... 49 4 RF Interface ................................................................................................... 51 4.1 RF Indicators ................................................................................................. 51 4.2 RF Antenna .................................................................................................... 54 4.2.1 Antenna Introduction ................................................................................ 54 4.2.2 Impedance Design Principles .................................................................. 54 4.2.3 Antenna Passive Test ............................................................................... 57 5 Reliability ....................................................................................................... 60 5.1 Temperature and Humidity Requirements ..................................................... 60 5.2 Reliability Indicators ....................................................................................... 60 5.3 ESD Indicators ............................................................................................... 62 6 Thermal Design ............................................................................................ 63 6.1 Overview ........................................................................................................ 63 6.2 Thermal Basis ................................................................................................ 63 6.3 Thermal Design ............................................................................................. 64 6.3.1 Main Board ............................................................................................... 64 6.3.2 Product Structure ..................................................................................... 65 7 Structure Specifications ............................................................................... 67 7.1 Appearance .................................................................................................... 67 7.2 Dimensions .................................................................................................... 68 8 Packaging and Production .......................................................................... 70 8.1 Packaging ...................................................................................................... 70 8.2 Storage .......................................................................................................... 73 8.3 SMT ............................................................................................................... 73 Appendix A Acronyms and Abbreviations .................................................... 74 Appendix B Reference Standards.................................................................. 76 2 Appendix C Reference Documents ............................................................... 77 FCC Conformance information ...................................................................... 78 Requirement per KDB996369 D03................................................................. 82 Contents 3 Applicable Model Applicable Model No. Applicable Model Description 1 MG661-EU/LA-

19 Support LTE FDD 4 Change History Change History V1.0 (2023-06-04) Initial version. 5 1 Product Overview 1 Product Overview 1.1 Product Introduction The MG661 module is a broadband wireless terminal product applicable to multiple bands for FDD. The following table lists the sub-models of the MG661 product. Table 1. Sub-models of the MG661 module Item MG661-EU-19 MG661-LA-19 LTE FDD Band 1/3/5/7/8/20/28 Band 2/3/4/5/7/8/28/66 ANT Main Main Memory 4MB Flash+8MB RAM 4MB Flash+8MB RAM Main indicates that the main antenna use a common circuit and work in a time-

sharing manner. 1.2 Product Specifications The product hardware has the following characteristics. Category Controller Memory Table 2. Basic configuration Description 500MHz 4MB Flash+8MB RAM 6 Table 3. Baseband characteristics Category Description 1 Product Overview USB 1: USB 2.0, can be used for AT communication, capturing log and upgrading software version; I2C 3: Support standard mode 100KHz and fast mode 400KHz, and the internal software of the module is pulled up by default SPI 3: Two dedicated SPI interfaces (SPI CAM and SPI LCD) and one dedicated SPI FLASH interface ADC 2: Supports 12-bit ADC, voltage range 0 to VBAT UART 2: Used for sending AT Function interface commands or data transmission, the baud rate defaults to 115200bps, and the main serial port UART1 can support RTS and CTS hardware flow control GPIOs KEYs DEBUG_UART 1: Debug serial port for AP log output, and the baud rate is 2M SIM 2: Support 1.8 V and 3V cards, support hardware two SIM card interfaces, but whether to support dual cards is mainly Peripheral interface distinguished by software LCD 1 CAM 1 PCM/I2S: For external audio Codec Table 4. RF characteristics Category Description Antenna interface Main antenna 1 7 1 Product Overview The above supported interface description is based on the default definition of MG661 pins. Some pins in the OPEN version can be reused for other functions. For details, see the GPIO reuse table. The DEBUG_UART function corresponds to pins pin 38 and 39. By default, the function is UART4 and can be used to capture AP logs. Module pin 7, 58 can be reused as UART2 function, which is used to output CP log with baud rate of 8M. Two groups of USIM interfaces are supported by the hardware, but whether the module supports dual cards is mainly distinguished by software. The single card only supports SIM1 function of pin 11, 12, 13 and 14 by default. 1.3 Hardware Block Diagram The MG661 product hardware consists of the following parts:

Baseband part: CPU, memory, 26M RF part: RF Transceiver, RF PA, RF filter antenna The following figure shows the internal structural block diagram. 8 1 Product Overview Figure 1. Hardware block diagram 1.4 Description of Development Board To help customers develop MG661 modules, Fibocom provides MG661development boards

(shared with MC981 series) for controlling or testing modules. For more details, see Fibocom_MC981-CN_ADP User Guide. 9 BasebandTransceiverRAM & FlashRESET_NUSB_BOOTLCD&CAMUSB(U)SIM*2PCMI2CsSPIKeypadsUARTSTATUSVBATVBATPWRKEYVDD_EXTANT_MAIN/ANT_WIFI_SCANSWITCHDuplexPA26MHZDXCOTXTxNET_STATUS 2 Pin Definition 2 Pin Definition 2.1 Pin Attributes The following attributes are used to describe pins. Table 5. Pin attributes Attribute Description No. Pin No. Name Pin Name Direction of pin signal PI: Power Input PO: Power Output DI: Digital Input DO: Digital Output I/O DIO: Digital Input and Output AI: Analog input AO: Analog Output AIO: Analog Input and Output OD: Open Drain G: Ground Voltage Power domain of the interface Description Specific meaning of the pin and processing method when it is not used 2.2 Pin Distribution The MG661 module is designed with LGA package and available with a total of 109 pins. 10 The distribution of pins is shown in the following figure. 2 Pin Definition Figure 2. Pin distribution Keep the NC pin unconnected. Connect all GND pins to the ground network. The functions of reserved pins 4, 5, 6, 8, 26, 44, 96, 99, 102, 104, 105 and 106 in the figure have been debugged OK. For details, see the next section. 11 2 Pin Definition Pin79 can be reused as USIM1_DET and SPI_FLASH_CS functions. When using external FLASH, SIM hot plug can be implemented by using other GPIO. If the USB_BOOT/KEYIN0 pin is pulled low or high before starting up, or the key combined with KEYOUT0 is pressed, the module will enter the download mode. Please be careful not to trigger it by mistake during design. It is recommended to pull down USB_BOOT to enter the download mode. KEYIN1 and KEYIN2 cannot be pulled low before starting up, otherwise it will enter the abnormal download mode. The power output of pin 99 LCD_VDDIO is the power domain voltage of the relevant pin of LCD. The default voltage of LCD_VDDIO is 1.8 V, that is, the voltage of LCD related pins 49, 50, 51, 52, 53 and 78 is 1.8 V. The reserved function LCD_VDD of pin 3 is occupied internally and has power-off control for sleep and flight modes. Therefore, it is not recommended for external use. If you must use it, check whether the current and timing of each application scenario meet the requirements. Reserve pin 38/39 for the AP and pin 57/58 for the CP LOG. The pin is not anti-backflow. When using, please note that after the module pin is powered off (shutdown or in PSM mode), there shall be no external high level or pull-up. If pin 57/58 is occupied, other pins that can be reused for UART2 function can be reserved as CP log port. To avoid interference, wiring is prohibited on the surface of the bottom plate below the module. 12 2 Pin Definition 2.3 Pin Details Unused pins are left unconnected. Pins with * indicate that there are notes at the end of the section. Table 6. Power interfaces Pin No. Pin Name I/O Power domain Description 42, 43 VBAT PI 3.4V4.5V 24 VDD_EXT PO 1.8V Baseband/RF power input (3.4 4.5V) 3.8 V is recommended Digital level, 1.8V output, with the maximum current of 100mA Table 7. Control interface Pin No. Pin Name I/O Power Description Domain 15 RESET_N DI VBAT resets. When the module is working, pull down RESET_N 100 ms or longer, and then release it. The module 7 PWRKEY DI VBAT Pins are internally pulled up to VBAT, and no external pull up is required. In power-off state, pull down PWRKEY for a long time, and the module automatically powers on. In power-off state, pull the PWRKEY for 2s or longer, and then release it, the module powers on. In power-on state, pull the PWRKEY for 3.1s or longer, and then release it, the module powers off. 13 Pin No. Pin Name I/O Power Description Domain 2 Pin Definition Pins are internally pulled up to VBAT, and no external pull up is required. If USB_BOOT is pulled down to ground or up to 1.8V, the module will enter the download mode if it is 82 USB_BOOT/KEYIN0 DI 1.8V powered on or reset. It is recommended to pull down USB_BOOT to enter the download mode. Table 8. Baseband interface Pin No. Pin RESET Name VALUE I/O Power Domain Description 5 6 GPIO29 PU DIO 1.8V GPIO pin GPIO30 PU DIO 1.8V GPIO pin 44 VRTC*

PI 3.0V RTC power input, not recommended, can be suspended Current source input pin, can be connected to the cathode of the 102 ISINK

PI

backlight, by adjusting the ISINK current to adjust the brightness of the backlight 1, 10, 27, 34, 36-37, 40-41, 45-

GND

G

Ground 48, 70-73, 88-95 14 2 Pin Definition Pin No. Pin RESET Name VALUE I/O Power Domain Description 2, 3, 97, 98 NC

Suspended Pin No. Pin Name I/O 35 ANT_MAIN 104 GRFC_6*

105 GRFC_7*

DO DO Table 9. RF interface Power Description Domain

Main antenna 1.8V RF control signal, not recommended 1.8V RF control signal, not recommended Table 10. LPG interface Pin No. Pin Name I/O 16 NET_STATUS DO 25 STATUS DO RESET VALUE PD PU Power Description Domain 1.8V Network status indication 1.8V Operating status indication Pin No. Pin Name I/O Table 11. USB interface Power Description Domain 61 USB_VBUS PI 5.0V USB insertion detection, typical value: 5 V 60 USB_DM IO 3.3V 59 USB_DP IO 3.3V USB differential data signal (), ensure 90 differential impedance USB differential data signal (+), ensure 90 differential impedance 15 2 Pin Definition Table 12. SPI interface Pin No. Pin Name I/O RESET VALUE Power Domain Description 101 SPI_FLASH_CLK DO PD 1.8V SPI clock signal 100 107 108 109 SPI_ FLASH_SIO0 SPI_ FLASH_SIO3 SPI_ FLASH_SIO1 SPI_ FLASH_SIO2 DIO PD 1.8V DIO PD 1.8V DIO PD 1.8V DIO PD 1.8V SPI data transmission SPI data transmission SPI data transmission SPI data transmission 79 SPI_ FLASH_CS DO PD 1.8V SPI chip selection Table 13. I2C interface Pin No. Pin Name I/O RESET Power Description VALUE Domain PU I2C clock signal, internal software pull-up, external 1.8V 67 I2C2_SCL OD 1.8V hardware pull-up can be reserved, can be suspended when not in use PU I2C data signal, internal software 66 I2C2_SDA OD 1.8V pull-up, external 1.8V hardware pull-up can be reserved, can be suspended when not in use 68 I2C3_SCL OD PU 1.8V I2C clock signal, internal software pull-up, external 1.8V 16 Pin No. Pin Name I/O RESET Power Description VALUE Domain 2 Pin Definition hardware pull-up can be reserved, can be suspended when not in use PU I2C data signal, internal software 69 I2C3_SDA OD 1.8V pull-up, external 1.8V hardware pull-up can be reserved, can be suspended when not in use Table 14. Debug interface Pin No. Pin Name I/O RESET VALUE Power Domain Description 39 DBG_TXD DO PU 1.8V Debug serial port transmitting 38 DBG_RXD DI PU 1.8V Debug serial port data receiving Table 15. USIM interface Pin No. Pin Name I/O RESET Power VALUE Domain Description 11 12 13 USIM_D ATA USIM_R ST USIM_C LK DIO

1.8V/3V

(U)SIM data signal line, SIM_DATA has internal pull-up, external pull-up can be reserved to SIM_VDD, keep NC first DO

1.8V/3V

(U)SIM reset signal line DO

1.8V/3V

(U)SIM clock signal line 17 2 Pin Definition Pin No. Pin Name I/O RESET Power VALUE Domain Description 14 79 64 63 62 65 USIM1_ VDD USIM1_ DET USIM2_ DATA USIM2_ RST USIM2_ CLK USIM2_ VDD PO

1.8V/3V automatically identifies 1.8V or

(U)SIM power supply, the module 3.0V (U)SIM card DI PD 1.8V SIM 1 detection DIO PD 1.8V/3V

(U)SIM data signal line, SIM_DATA has internal pull-up, external pull-up can be reserved to SIM_VDD, keep NC first DO PD 1.8V/3V

(U)SIM reset signal line DO PD 1.8V/3V

(U)SIM clock signal line PO

1.8V/3V automatically identifies 1.8V or

(U)SIM power supply, the module 3.0V (U)SIM card Table 16. UART interface Pin No. Pin Name I/O RESET Power VALUE Domain Description 22 MAIN_RTS DO PU 1.8V 23 MAIN_CTS DI PU 1.8V Main serial port UART1 transmitting request Main serial port UART1 clears to send 20 MAIN_RI DO PD 1.8V Ring prompt 18 2 Pin Definition Pin No. 21 19 Pin Name I/O RESET Power VALUE Domain Description MAIN_DCD DO PD 1.8V Carrier detection MAIN_DTR DI PD 1.8V Data ready 18 MAIN_TXD DO PU 1.8V 17 MAIN_RXD DI PU 1.8V Main serial port UART1 data transmitting Main serial port UART1 data receiving 29 28 AUX_TXD DO PD 1.8V UART1 data transmitting AUX_RXD DI PD 1.8V UART6 data receiving Pin No. Pin Name I/O Table 17. ADC interface Power Description Domain 9 96 Pin No. ADC0 ADC1 AI AI VBAT Analog-to-digital conversion 0 VBAT Analog-to-digital conversion 1 Table 18. CAM interface Pin Name I/O RESET Power VALUE Domain Description 54 CAM_MCLK DO PD 1.8V CAMERA clock signal 57 CAM_I2C1_SCL OD PU 1.8V 58 CAM_I2C1_SDA OD PU 1.8V CAMERA I2C clock signal, internal software pull-up, external 1.8V hardware pull-up can be reserved, can be suspended when not in use CAMERA I2C data signal, internal software pull-up, external 1.8V 19 2 Pin Definition Pin No. Pin Name I/O RESET Power VALUE Domain Description hardware pull-up can be reserved, can be suspended when not in use 80 CAM_SPI_CLK DO PD 1.8V CAMERA SPI clock signal 55 CAM_DATA0 DIO PD 1.8V CAMERA MIPI data D0 56 CAM_DATA1 DIO --

1.8V CAMERA MIPI data D1 81 CAM_PWDN DO PD 1.8V CAMERA POWER DOWN signal 8 CAM_VDD PO

2.8V 106 CAM_VDDIO PO

1.8V CAMERA power supply with a maximum current of 100mA CAMERA IO port power supply with a maximum current of 100mA 103 CAM_RST DO PD 1.8V CAMERA reset signal Table 19. LCD interface Pin No. Pin Name I/O RESET VALUE Power Domain Description 50 LCD_SIO DIO PD LCD_VDDIO

(1.8V) LCD SPI bus data bit 49 LCD_RST DO PD LCD_VDDIO LCD SPI bus reset

(1.8V) signal 51 LCD_SDC DO PD LCD_VDDIO

(1.8V) LCD SPI bus data address switching signal 53 LCD_CLK DO PD LCD_VDDIO 1.8V LCD bus clock signal 52 LCD_CS DO PD LCD_VDDIO LCD bus chip selection 20 Pin No. Pin Name I/O RESET VALUE

2 Pin Definition Power Domain Description

(1.8V) LCD analog power supply, with a maximum current of 4 LCD_VDD PO 2.8 V 100mA, shared with

module internal switch, can not be enabled or disabled separately LCD IO interface power supply with a maximum current of 200mA Voltage ranges from 1.8V to 3.2V can be 99 LCD_VDDIO PO 1.8V-3.2V configured, after this power supply voltage changes, LCD pins

(PIN 49-53, 78) voltage will change The default voltage is 1.8V 78 LCD_TE DIO PD LCD_VDDIO LCD synchronization

(1.8V) signal Table 20. KEY interface Pin No. Pin Name I/O RESET Power VALUE Domain Description 83 KEYOUT0 DO PD 1.8V KEY output 0 76 KEYOUT2 DO PD 1.8V KEY output 2 21 2 Pin Definition Pin No. Pin Name I/O RESET Power VALUE Domain Description 77 KEYIN2 DI PU 1.8V KEY input 2, cannot be pulled down externally before boot, otherwise the module will enter abnormal download mode 85 KEYOUT6 DO PD 1.8V KEY output 6 84 KEYIN6 DI PD 1.8V KEY input 6 86 KEYOUT1 DO PD 1.8V KEY output 1 87 KEYIN1 DI PU 1.8V before boot, otherwise the module will enter the abnormal download mode KEY input 1 and cannot be pulled down 74 KEYOUT5 DO PD 1.8V KEY output 5 75 KEYIN5 DI PD 1.8V KEY input 5 Table 21. PCM/I2S interface Pin Name I/O RESET Power Description VALUE Domain PCM_CLK DO PD 1.8V PCM clock PCM_SYNC DO PD 1.8V PCM data synchronization signal PCM_DIN DI PD 1.8V PCM data input PCM_DOUT DO PD 1.8V PCM data output I2S_MCLK DO PD 1.8V I2S main clock output signal Pin No. 30 31 32 33 6 22 2 Pin Definition The PIN44 VRTC pin is input by an external battery to maintain the voltage value after the module is powered down If it is necessary to use VRTC to maintain the reference clock in the module power-off state, it is not possible to use the PWRKEY automatic power-on design, otherwise it will lead to the failure of secondary power-on after shutdown. In addition, if the VRTC pin is used, the module must go through the normal shutdown process, and the module VBAT cannot be powered down directly, otherwise the clock will not be saved. PIN104/105 GRFC_6/7: RF tuning antenna control interface. If it is necessary to use it, please confirm with Fibocom. All RESET VALUEs in the table refer to the corresponding state of the pin of the module at RESET instant (during the duration of RESET low level) (at this time, the pin corresponds to the Function 0 in the GPIO multiplexing table), PU represents high level, and PD represents low level. For detailed GPIO state, please refer to the GPIO multiplexing table. Especially when enabling electro-

acoustic devices, or controlling motors, relays and other devices, please refer to the GPIO multiplexing table to select the appropriate GPIO. 23 3 Application Interfaces 3 Application Interfaces 3.1 Power Interfaces 3.1.1 Electrical Indicators Table 22. Electrical indicators Minimum Typical Maximum Value Unit Value Value VBAT power supply Digital input high level Digital input low level Digital output high level Digital output low level 3.4 1.6

1.2 0.3 3.8 4.5

0.3

0.5 V V V V V Table 23. Limit voltage indicator Minimum Maximum Unit Value Value VBAT power supply 0.3 4.6 Indicator Power supply voltage Logic level Indicator Power supply voltage USB_VBUS USB insertion detection 0.3 5.2 V V 24 3 Application Interfaces Minimum Maximum Unit Value Value Level power supply voltage of digital I/O 0.3 2.0 V Indicator GPIO 3.1.2 Power Input Background The performance of the power supply such as its load capacity, ripple etc. will directly affect the operating performance and stability of the module. If the power supply capacity is insufficient and the power supply voltage instantaneous drops, the module may be powered off or restarted. The following figure shows the power supply limit. Figure 3. Power supply limit The ripple of the power supply should be lower than 300 mV, and the line ESR (equivalent series resistance) should be < 150 m. When the module is working, it is necessary to ensure that the DC power supply voltage is between 3.4V and 4.5V, including voltage sag, ripple and spike. The module power supply is far away from interference sources such as antennas. Schematic Diagram Design VBAT is the power pin of the module. 25 Burst transmitBurst transmitmin:3.4VPower supplyRipple 300mVDrop VBAT 3.4V The reference design is shown in the following figure. 3 Application Interfaces Figure 4. Reference power supply design Design Description Table 24. Design description Design Consideration Mode Recommended Parameter To reduce power fluctuations Regulating during module operation capacitor Use a capacitor with low ESR 220uF x 2, 10uF, 22uF LDO or DCDC power supply requires capacitor with a capacitance of no less than 440uF. Battery power supply requires capacitance of 100uF to 220uF. Filter out interference caused by clock and digital signals. Eliminate low-frequency and intermediate-frequency RF interference. Filter capacitor 1uF, 100nF Decoupling capacitor 33pF, 8pF 26 3 Application Interfaces It is recommended to reserve the TVS tube position for the VBAT power supply. Recommended model: ESDH4V5P1/ESD5651N. PCB Design To reduce the equivalent impedance of the VBAT routing, the routing from the external power supply to VBAT is required to be as short and wide as possible (it is recommended that the routing width of VBAT should be at least 2 mm/2A to ensure sufficient power supply capacity). The capacitors with a small capacitance should be placed close to the module, and the ground plane of the power supply part should be as complete as possible. Power supply layout and routing are far away from interference sources such as antennas. 3.1.3 Power Output The power output interface of the module is described in the following table. Table 25. Module power interface Pin No. Pin Name I/O Description DC Parameter Minimum Typical Maximum Value (V) Value Value (V)

(V) 24 VDD_EXT PO Digital level 1.8V, 1.74 1.8 1.85 100mA 3.2 Control Interfaces 3.2.1 Power-on Schematic Diagram Design The startup sequence of the module is shown in the following figure. 27 3 Application Interfaces Figure 5. Power-on sequence Before pulling down the PWRKEY pin, make sure that the VBAT voltage is stable. It is recommended that the time interval between VBAT power-on and pulling PWRKEY pin down be no less than 30ms, and the time for pulling PWRKEY pin down is recommended to last for 2 s (the minimum time for pulling PWRKEY down is 700ms). One way is to use an OC/OD drive circuit to control the PWRKEY pin. The reference circuit is shown in the following figure. Figure 6. OC/OD drive reference circuit The other way is to use a button switch. A TVS (ESD9X5VL-2/TR is recommended) should be located close to the button to implement ESD protection. The reference circuit is shown in the following figure. 28 3 Application Interfaces Figure 7. Button control reference circuit Automatic power-on design: If the module needs to be powered on automatically, the PWRKEY pin can be connected in series with the resistor to ground (recommended resistance value is 1K or 0). In this way, the module sleep current will increase by about 0.2mA, and the module can only be directly powered off when it is powered down. In addition, if you use the automatic power-on design, ensure that the battery/power supply voltage is not lower than the module automatic power-off voltage, otherwise you need to re-

power up and down again or plug and remove the USB to power on normally. Before pulling down the PWRKEY pin, make sure that the VBAT voltage is stable. It is recommended to control the interval from power-up by VBAT to PWRKEY pin pull-down no less than 30ms. It is not recommended to design pull-down resistor larger than 1K for automatic power-on, otherwise it cannot guarantee that PWRKEY voltage is within the range of effective low level, which will lead to probability failure of boot. 3.2.2 Power-off Background The module can be powered off through the following ways:

Low voltage power-off: The module is powered off when the power supply voltage is lower than the rated minimum operating voltage. The module does not log out from a base station. 29 3 Application Interfaces Hardware power-off: The module is powered off when the PWRKEY pin is pulled down for at least 3.1s. Software power-off: The module is powered off through the AT+CPWROFF command. This mode applies only to non-main control modules. When the module is working properly, do not cut off the power supply of the module immediately to avoid damaging the internal flash and causing data loss. It is strongly recommended to power off the module by a normal way before cutting off the power supply. When using the software to power off the module, ensure that the PWRKEY pin is always at the high level after the power-off command is executed. Otherwise, the module will automatically power on again. Software command shutdown cannot be realized during automatic power-on design. Avoid the low voltage power-off scenario when designing automatic power-on, otherwise it may lead to the failure of secondary power-on. The hardware power-off sequence is follows. Figure 8. Hardware power-off sequence 30 After the PWRKEY signal is released, the next power-on trigger can be performed at least 5 seconds later. This interval is reserved for the module to perform the shutdown process and release the power of the peripheral circuit connecting with module interface. 3 Application Interfaces 3.2.3 Reset Background When the module needs to be restored to its initial state, it can be reset. The module supports hardware reset and software reset. Hardware reset The hardware reset timing sequence is as follows. Figure 9. Hardware reset sequence Set RESET_N to low level and hold for at least 100ms, then release. Similar to the power on/off control circuit, the reset reference circuit is shown in the following figure, and the RESET_N pin can be controlled using the OC/OD driver circuit or the button. 31 3 Application Interfaces Figure 10. OC/OD drive reset reference circuit Figure 11. Button control bit reference circuit Reset signal is a sensitive signal, so it is recommended to add a debounce capacitor (< 10 nf) close to the module. Software reset AT+CFUN=15 PCB Design RESET_N is a sensitive signal. During PCB layout, keep this signal far away from RF interference. PCB routes must be protected using GND and kept away from edges of PCBs to avoid module reset due to ESD problems. 32 3 Application Interfaces 3.2.4 Download The MG661 module supports USB download function. To enter the download mode, it is necessary to pull down USB_BOOT to ground or pull up to VDD_EXT, and then power on or reset the module. The module will enter the download mode. It is recommended to pull down USB_BOOT to ground to enter the download mode. In the download mode, the module can be upgraded by the software through the USB interface. The following figure shows the reference circuit. Figure 12. Reference circuit for entering the download mode It is recommended to add 1k resistor and TVS tube near the module. 3.3 Baseband Interface For details about how to use the GPIO multiplexing function of MG661 Open models, see Fibocom_MG661_GPIO Function Multiplexing Table. 3.3.1 USB 2.0 Background USB (Universal Serial Bus) is an external bus standard used to regulate the connection and communication between computers and external devices. It is the interface technology applied in PC field. USB is generally used for debugging, or for software upgrades. 33 Schematic Diagram Design The interface circuit design is shown in the following figure. 3 Application Interfaces Figure 13. Interface circuit design Since the module supports USB 2.0 High-Speed, it is recommended to use TVS with a capacitance of 0.5 pF on the USB_DM/DP differential signal line. It is recommended to connect a 0-ohm resistor on each USB_DM/DP differential line to facilitate debugging. USB enumeration requires an additional voltage to USB_VBUS. Otherwise, USB cannot be enumerated normally. The voltage range is 3.5V to 5.5V. PCB Design USB_DP and USB_DM are high-speed differential signal lines that should be equal in length and parallel to avoid right-angle route. The difference of cabling length is controlled within 2 mm, and the differential impedance is controlled at 9015%. The USB data cable cannot be routed under the crystal, oscillator, magnetic device, or RF signal. It is recommended to take an inner differential cable that is wrapped with copper connected to the ground at all directions. The ESD protector for the USB data cable must be placed close to the USB interface. The parasitic capacitance of the ESD protector must not exceed 1 pF, and a TVS with a capacitance of 0.5pF is recommended. USB 2.0 differential signal cable should be laid on the signal layer nearest to the ground. 34 If the USB function is not used, you are advised to reserve test points for easy log capture 3 Application Interfaces and software upgrade. 3.3.2 UART Background UART is a Universal Asynchronous Receiver/Transmitter. It converts a parallel input signal into a serial output signal. UART is generally used to communicate with PCs, including monitoring debuggers and other devices, such as EEPROM. Schematic Diagram Design The module has main serial ports MAIN_UART and AUX_UART, and debugging serial port DEBUG_UART. MAIN_UART supports baud rates of 1200bps, 2400bps, 4800 bps, 9600 bps, 19200 bps, 38400 bps, 57600 bps, 115200 bps, 230400 bps, 460800 bps, 921600 bps, 1000000bps, 1500000bps and 2000000bps. The default baud rate is 115200 bps, used for data transmission and AT command exchange. Sleep and wakeup are supported. AUX_UART is a set of auxiliary serial ports that can be configured as UART6 or UART3. It supports baud rates of 1200bps, 2400bps, 4800 bps, 9600 bps, 19200 bps, 38400 bps, 57600 bps, 115200 bps, 230400 bps, 460800 bps, 921600 bps, 1000000bps, 1500000bps and 2000000bps. The default baud rate is 115200 bps. The debugging serial port DEBUG_UART supports 2000000bps baud rate for module AP log output. The baud rate is 2M. The serial port level of the MG661 module is 1.8V. If the level of the customer host system is 3.3V or others, it is necessary to add a level converter in the serial port connection between the module and the host. The following figures show the design of reference circuit of the serial port level conversion chip. You can design the input and output circuits of the dashed line part by referring to the solid line part in the figure 15, but pay attention to the connection direction. 35 3 Application Interfaces Figure 14. Reference circuit 1 for serial port level conversion Figure 15. Reference circuit 2 for serial port level conversion The level conversion circuits do not apply to applications whose baud rate exceeds 460Kbps. Pay attention to TX/RX and CTS/RTS connection. The pull-up resistor of the serial port level conversion circuit of triode or MOS tube is recommended to be 10K. 3.3.3 I2C Background 36 3 Application Interfaces The I2C bus is a simple, bidirectional two-wire synchronous serial bus. It only requires a data line and a clock line to transfer information between devices connected to the bus. It is mainly used in the communication between multiple integrated circuits (ICs) in the system. Schematic Diagram Design The module I2C interface has been pulled up by software by default, and external hardware pull-up is required to be reserved. When I2C has more than one peripheral, please ensure the uniqueness of every peripheral address. When some peripherals need to occupy I2C bus frequently, it is not recommended to share it with other devices. The I2C supports standard mode 100Kbps and fast mode 400Kbps communication rates. PCB Design I2C PCB traces and peripherals require protection from interference. 3.3.4 PCM/I2S The MG661 module enables external codec. Table 26. PCM/I2S interface description Pin No. Pin Name I/O Power Description Domain 30 31 32 33 6 PCM_CLK DO 1.8V PCM clock PCM_SYNC DO 1.8V PCM data synchronization signal PCM_DIN DI 1.8V PCM data input PCM_DOUT DO 1.8V PCM data output I2S_MCLK DO 1.8V I2S main clock output signal Background 37 3 Application Interfaces The module digital voice interface supports I2S and PCM transmission standards. Schematic Diagram Design According to the corresponding connection of the reference design of the codec chip used, the power supply and IO level are required to meet the requirements of the codec chip and match the module. When the customer uses the external codec and audio power amplifier of the module interface, it is recommended that the control signal such as the enable of the audio power amplifier or I2C is also connected to the module to facilitate the debugging of the timing sequence and solve the audio problems such as pop sound. It is recommended to use an independent power supply for chip power supply or ensure that the power supply is clean and noiseless. RC (0/33pF) filtering is recommended for I2S signals. Figure 16. Schematic diagram of LCD reference circuit PCB Design The audio is partially protected or divided to ensure that the grounding is clean. Keep away from other interference sources. Audio signal design requires filtering isolation and packet protection. I2S_MCLK signal has a high speed, so it must be isolated from other high-frequency or 38 3 Application Interfaces sensitive signals to avoid interference. 3.3.5 SIM Background The module can be connected to the network only after the SIM card is inserted. The module supports 1.8 V and 3 V SIM cards. Schematic Diagram Design There are the following scenarios:

SIM card slot with detection signal: supports detection of SIM card insertion and removal, including normally opened card slot and normally closed card slot. It is used together with the hot plug function. The (U)SIM card with hot plug detection function is recommended. SIM card slot without detection signal: does not support detection of SIM card insertion and removal. Refer to the following design for the normally closed SIM card slot. Figure 17. Normally closed SIM card slot Refer to the following design for the normally opened SIM card slot. 39 C6USIM_VDDR2USIM_RESETUSIM_PRESENCEUSIM_CLKUSIM_DATAR4R3R7C5C4C3C1C2RV5RV1RV2RV3RV4MODULEVIO_1V8R6R5SIM_CONNECTORSIM016-8P-220PSet to high level detection SIM cardVCCGNDRSTDETCLKDATAGNDGNDPOLVPP1238561097422R22R22R47K4.7KSIMNC0.1uF33pF33pF33pF33pF33pFRV1-RV5 Recommend EGA10402V05A2 3 Application Interfaces Figure 18. Normally opened SIM card slot USIM_DATA has internal pull-up inside the module, and external pull-up can be reserved to keep NC. The recommended model for RV1 to RV5 is EGA10402V05A2. For SIM card slot with no card detection, the USIM_PRESENCE pin of the module is suspended or connected in series with 10K resistor to ground. The hot plug function is disabled by software default. PCB Design Layout key points:

Reserve capacitor filter for SIM signal line to prevent interference from high frequency signal. SIM card and routing should be away from EMI interference source, such as power circuit, RF circuit, antenna, and high-speed digital signal circuit. ESD components of SIM card should be close to SIM card slot interface. When routing antenna feeder line, please keep the line away from power device, and avoid the line paralleling to antenna copper foil. 40 C6USIM_VDDR2USIM_RESETUSIM_PRESENCEUSIM_CLKUSIM_DATAR4R3R7C5C4C1C2RV5RV1RV3RV4MODULESIM_CONNECTORVCCGNDRSTCLKDATAGNDGNDVPP1235687422R22R22R10KSIM0.1uF33pF33pF33pF33pFRV1-RV5 Recommend EGA10402V05A2 3 Application Interfaces The filter capacitor and ESD device of SIM signal cable are placed close to the SIM card slot. Less than 11pF capacitor is recommended for ESD device. Routing points:

To reduce EMC problem, keep SIM signal line away from RF cable, power line, clock line and high-speed data line. Do not route the adjacent cables with the SIM signal line; otherwise, the cabling poses an EMI risk. Design the other cables and SIM signal line to be perpendicular with each other to reduce risk. Ensure the ground connectivity and integrity of PCB environment and the connectivity and integrity of SIM_GND. The nearest path connects to a clean system ground. To avoid mutual interference, please separately ground SIM_CLK and SIM_DATA. If conditions do not permit, at least the SIM signal must be grounded as a set. The SIM signal line should be routed along the inner layer. SIM card connector is covered by metal shield shell to improve EMS. To ensure the integrity of signal, the cabling length from the module to SIM card should not exceed 100mm. Longer cable will reduce signal quality. It is recommended to make a clearance design for the PCB directly under the shrapnel of the SIM card connector to avoid the green oil on the surface of the PCB being worn down when the shrapnel is pressed down, resulting in a short circuit between the SIM card signal line and the ground. Hot Plug The MG661 module supports (U)SIM card hot-plug function. The module determines whether

(U)SIM card is in place by detecting the status of USIM_PRESENCE pin. (U)SIM card hot-

plug function is disabled by default and needs to be enabled before use. When the USIM_PRESENCE is at a high level, the module initializes the (U)SIM card after detecting that the (U)SIM card is inserted, and registers the network after reading the (U)SIM card 41 information. When the USIM_PRESENCE is at a low level, the module determines that the

(U)SIM card is removed and does not read it. The SIM card hot plug function can be configured by running the AT+MSMPD command. The 3 Application Interfaces AT commands are described as follows. AT+MSMPD=1, enable hot plug. AT+MSMPD=0, disable hot plug. AT+SIMPHASE=1, set high level detection. AT+SIMPHASE=0, set low level detection. RF Interference Handling In practice, RF interference is quite normal. Here are some solutions. Antenna coupling interference Reason:

When antenna transmits with high power, it causes direct interference to the SIM signal. When antenna transmits with high power, it is coupled to the ground, reducing the stability of the whole system and causing indirect interference to the SIM signal. Adjust the filter capacitance value the of SIM signal. Use a longer antenna and keep it far away from the SIM card. Shield the interference signal to protect the SIM card. Pay attention to the design of the ground, especially the connectivity of SIM card, module and the system ground. Fully ground each layer of PCB and increase holes to enhance the EMC performance of the system. 42 RF coupling will cause interference to GND. Adjust the capacitance values of capacitor and ESD components or even remove the capacitor (if it is necessary) to avoid the 3 Application Interfaces interference. PCB crosstalk:

Reason:

Other signal line on the main board has crosstalk with the SIM signal through the PCB routing. Antenna interrupted signal has crosstalk with the SIM signal through the PCB routing. Fluctuations of power has crosstalk with the SIM signal through the PCB routing. Adjust the filter capacitance value the of SIM signal. Find out the interference source, and change the board specifically. 3.3.6 ADC Background An analog-to-digital converter (ADC) converts analog signals into digital values for use in processing and control systems. It can be used for voltage detection and other external circuits. Schematic Diagram Design The module provides two ADC interfaces, send the AT+MMAD=<INDEX> command (INDEX is the ADC channel) can read the voltage value of the channel. The ADC voltage ranges from 0 to VBAT, with 12-bit resolution and sampling accuracy from 20mV to 50mV. When using the ADC function, it is recommended to connect a 1K resistor in serial mode to enhance ESD protection. PCB Design 43 It is recommended to ground ADC signal lines to improve ADC voltage measurement 3 Application Interfaces accuracy. 3.3.7 Status Indication Background Table 27. Status indication pin Pin No. Pin Name I/O Power Description Domain 16 25 NET_STATUS DO 1.8V Network status indication STATUS DO 1.8V Operating status indication The PIN16 of the MG661 module is the network status indication signal interface. It is used to drive the status indicator. The following table describes the working status of the module network indicator. Table 28. Working status of the network status indicator Mode Level Status of Network Indicator Pin (PIN16 NET_STATUS) 1 Slow flash (200 ms high/1800 ms low) Description No SIM card SIM pin Registering with the network (T < 15s) Failed to register with the network 2 3 Slow flash (1800 ms high/200 ms low) Standby Quick flash (120 ms high/120 ms low) Establishing a data connection 44 3 Application Interfaces 4 High level Sleep status Schematic Diagram Design The reference circuit of network status indicator is shown in the following figure. Figure 19. Network status indicator reference circuit Please reserve the 4.7K and 47K positions for voltage division to ensure that the voltage of the triode VBE is less than the starting voltage of the triode in startup, reset and wake up scenarios, and avoid power consumption increase caused by LED work. When the LED is required to work, the voltage of the VBE is greater than the starting voltage of the triode. STATUS indicates the operational status of the module. STATUS will output a high level when the module is powered on normally. The definition of the STATUS pin is described in the following table:

Table 29. STATUS operating status Pin I/O Description Note STATUS (PIN25) DO Operating status indication Keep unsuspended when not in use 1.8V voltage domain 45 ModuleNET_STATUS4.7K47K2.2KVBAT 3 Application Interfaces Figure 20. Reference circuit of STATUS operating status 3.3.8 LCD Interface The MG661 module provides a set of LCD interface. The LCD interface supports a module with the maximum resolution of 240320 (QVGA) @30fps LCD display and support 3-wire 9bits and 4-wire 8 bits SPI mode data transmission. Refer to the reference design for the LCD peripheral circuit design. 3.3.9 Camera Interface The MG661 module provides a set of CAMERA interface. The camera interface supports up to 30 W@15fps pixel sensor and supports 1-bit or 2-bit SPI interface. See the reference design for the design of CAM peripheral circuits. 3.4 Operating Mode The module supports the following operating modes. 46 ModuleSTATUS4.7K47K2.2KVBAT 3 Application Interfaces Table 30. Operating modes Operating Mode Description The module is powered on, and it can be operated using the AT Standby mode

(IDEL) commands through the serial port. The module is registered with the network, there is no service processing in progress, and the module is ready for communication. This is the default operating mode after the module is powered on. The PMU stops supplying power to the baseband and RF sections, the Shutdown mode software stops working, and the serial port is disabled. However, the VBAT pin is still energized. The module is powered on and successfully registered with the Transmission mode network for service transmission. The module can be operated using the AT commands through the serial port. The module transmits data. When data transmission is completed, the module returns to the standby mode. The module is in light sleep state. It is connected to a network and can Sleep mode receive paging messages. In this mode, the module can switch to the standby mode. Flight Mode The wireless communication of the module is turned off. 3.4.1 Flight Mode Background When it is necessary to turn off the transmission and reception of wireless signals to avoid interference to the surrounding area, the flight mode can be enabled. When the module enters flight mode, the RF function is disabled. Entering mode Hardware control:

47 Send AT+GTFMODE=1 to enable flight mode control. When the W_DISABLE# pin is pulled high or suspended, the module is in the normal mode;

when the pin is pulled low, the module enters the flight mode. 3 Application Interfaces Software control:

Run the AT+CFUN=4 command to enter flight mode. Exiting mode Hardware control Pull the pin high, and the module is in normal mode. Software control:

Run the AT+CFUN=1 command to exit flight mode. Entering or exiting flight mode can be realized by using GPIO pins of modules and software settings, and customers can determine whether they need it according to the actual situation. 3.4.2 Sleep Mode Background The sleep mode is also called the low-power mode. To minimize battery loss, the module can be set to enter the sleep mode when it is idle to save power. The module in sleep mode can be awakened to the normal operating mode. Entering mode AT commands or WAKEUP_IN signal are used to set the module into sleep mode and wake-

up mode. Hardware control Send AT+GTLPMMODE=1, x to set the effective level of the WAKEUP_IN signal that sets the module into sleep or wake-up mode. The setting is effective after sending the AT+csclk=1 48 3 Application Interfaces command. x=0: Wake up the module by level. The module enters wake-up mode when WAKEUP_IN is pulled down and enters sleep mode at high level. x=1: Wake up the module by level. The module enters wake-up mode when WAKEUP_IN is pulled up and enters sleep mode at low level. Software control:

Run ATS24 to make the module to enter sleep. The wakeup hold time is subject to the </value>

in the ATS24 = [<value>] command. Send the ats24=2 command. The module enters sleep mode after 2s. The setting is not saved after the module power supply is disconnected. Send AT command through the main serial port to wake up the module. The hardware control module enters sleep or wake up mode through GPIO and software configuration. By default, it is implemented on WAKEUP_IN pin. Without WAKEUP_IN pin, DTR can also implement module sleep wakeup function. The OPEN version is optional for any GPIO implementation. 3.4.3 PSM Mode PSM is a power saving mode. Characteristics of terminal during non-service period in this mode:

1. Deep sleep, not receiving downlink data;

2. Only when the terminal actively sends the uplink data, the downlink data cached by the IOT platform can be received. The PSM feature needs to be configured on the network. After the module enters PSM mode, the power consumption can be reduced to 3A. To enter PSM, run the AT command AT+CPSMS=1. For details, see FIibocom_MC66x_Application Guide_PSM. 49 3 Application Interfaces Exiting the PSM mode:

1. Wake up through the PSM_EXT_INT pin, and active at high level. 2. Wake up by a PWRKEY button. 3. Wake up by TAU.

"*" indicates that the PSM function of the MG661 module is being debugged. PSM_EXT_INT is a PSM wake-up pin. The PSM_EXT_INT pin is not defined in MG661 separately. If PSM pin wake-up function is required, PSM_EXT_INT can be implemented on GPIO0-7 pin, such as DTR (PIN19) pin. 50 4 RF Interface 4 RF Interface 4.1 RF Indicators Table 31. RF indicators Indicator Description LTE system Operating band LTE FDD: B1/2/3/4/5/7/8/20/28/66 Modulation Transmitting power Uplink: QPSK/16QAM Downlink: QPSK/16QAM/64QAM 232dBm Peak rate LTE FDD: 10.296Mbps DL/5.160Mbps UL (Cat 1) Table 32. Transmitting power of each band System Band Tx Power (dBm) Description Band 1 232 10MHz Bandwidth, 1 RB Band 2 232 10MHz Bandwidth, 1 RB Band 3 232 10MHz Bandwidth, 1 RB Band 4 232 10MHz Bandwidth, 1 RB LTE FDD Band 5 Band 7 Band 8 232 232 232 10MHz Bandwidth, 1 RB 10MHz Bandwidth, 1 RB 10MHz Bandwidth, 1 RB Band 20 232 10MHz Bandwidth, 1 RB Band 28 232 10MHz Bandwidth, 1 RB Band 66 232 10MHz Bandwidth, 1 RB 51 Table 33. Receiving sensitivity at each band System Band Sensitivity (dBm) Description 4 RF Interface Band 1

-98.0 10MHz Bandwidth Band 2

-98.0 10MHz Bandwidth Band 3

-98.0 10MHz Bandwidth Band 4

-97.5 10MHz Bandwidth Band 5

-98.0 10MHz Bandwidth Band 7

-97.0 10MHz Bandwidth Band 8

-98.0 10MHz Bandwidth Band 20

-98.0 10MHz Bandwidth Band 28

-98.0 10MHz Bandwidth Band 66

-97.5 10MHz Bandwidth Table 34. Power consumption LTE FDD Parameter Ioff Airplane AT+CFUN=4 Isleep LTE FDD Paging cycle #64 frames (remove USB) Average Current (mA) 0.015 0.005 0.005 1.0 1.9 LTE FDD Paging cycle #64 frames (USB suspend) 2.7 52 Parameter 4 RF Interface Average Current (mA) LTE FDD Paging cycle #128 frames (remove USB) 1.5 LTE FDD Paging cycle #128 frames (USB suspend) 2.2 LTE FDD Paging cycle #256 frames (remove USB) 1.2 LTE FDD Paging cycle #256 frames (USB suspend) 1.9 IIDLE LTE FDD Paging cycle #64 frames (USB in place) LTE FDD Paging cycle #64 frames (remove USB) 25 11 LTE FDD LTE FDD Data transfer Band 1 @+23.5dBm 660 LTE FDD LTE FDD Data transfer Band 2 @+23.5dBm 660 LTE FDD LTE FDD Data transfer Band 3 @+23.5dBm 630 LTE FDD LTE FDD Data transfer Band 4 @+23.5dBm 630 ILTE-RMS LTE FDD LTE FDD Data transfer Band 5 @+23.5dBm 600 LTE FDD LTE FDD Data transfer Band 7 @+23.5dBm 650 LTE FDD LTE FDD Data transfer Band 8 @+23.5dBm 600 LTE FDD LTE FDD Data transfer Band 20 @+23dBm 550 LTE FDD LTE FDD Data transfer Band 28 @+23dBm 620 LTE FDD LTE FDD Data transfer Band 66 @+23dBm 630 The above power consumption data is the measured average value, and the floating range within 10% is normal. 53 4 RF Interface 4.2 RF Antenna 4.2.1 Antenna Introduction Antenna interface The module only has RF antenna pad. The RF cable can be connected to the antenna after PCB design of the RF signal line. Antenna classification According to the transmitting and receiving functions, it mainly includes:

Main antenna: The antenna is divided into built-in and external antenna, which is responsible for RF signal transmission and reception. The antenna is a sensitive device and is easily affected by the external environment. For example, the position of the antenna, the occupied space, and the surrounding grounding may affect the performance of the antenna. In addition, the RF cable connected to the antenna and the fixed antenna position will also affect the antenna performance. A shield or module antenna is placed away from the DCDC device on the customer mainboard to prevent RF signals from interfering with the DCDC device, resulting in out-of-

specification ripple output. 4.2.2 Impedance Design Principles For modules that do not have a RF connector, you need to route a RF cable to connect to the antenna feeding point or connector. It is recommended to use a microstrip line. The shorter the better. The insertion loss should be controlled less than 0.2 dB, and impedance should be controlled within 50. In general, the impedance of the RF signal route is determined by the dielectric constant of the material, the route width (W), the ground clearance (S) and the height of the reference ground plane (H). The control of the characteristic impedance of the PCB usually is 54 4 RF Interface implemented in two ways: microstrip route and coplanar waveguide. To illustrate the design principles, the following figures show the structural designs of microstrip route and coplanar waveguide when the impedance line is at 50. Microstrip cable complete structure Figure 21. Two-layer PCB microstrip line structure Coplanar waveguide complete structure Figure 22. Two-layer PCB coplanar waveguide structure 55 4 RF Interface Figure 23. Four-layer PCB coplanar waveguide structure (see ground layer 3) Figure 24. Four-layer PCB coplanar waveguide structure (see ground layer 4) In the design of RF antenna interface circuit, in order to ensure good performance and reliability of the RF signal, it is recommended to observe the following principles:

The impedance simulation tool should be used to accurately control the RF signal cable at 50 impedance. The GND pin adjacent to the RF pin should not have thermal welding plate and should be in full contact with the ground. The distance between the RF pin and the RF connector should be as short as possible. At the same time, avoid the right-angle route. The recommended route angle is 135. Attention should be paid to the establishment of the connection component package and 56 4 RF Interface the signal pin should be kept at a certain distance from the ground. The reference ground plane of the RF signal cable should be kept intact; adding a certain amount of ground holes around the signal and the reference ground can improve the RF performance; the distance between the ground hole and the signal cable should be at least 2 times the cable width (2*W). The equivalent capacitance of the TVS should be less than 0.5 pF. Add a -type circuit (two parallel component grounding pins are connected directly to the main GND) between the module and antenna connector (or feeding point) for antenna debugging. Two parallel components are directly connected across the RF cable, and the branch must not be pulled out. Figure 25. Antenna interface peripheral circuit 4.2.3 Antenna Passive Test You will need: network analyzer and anechoic chamber. The passive test evaluates the radiation performance of the device by focusing on the radiation parameters like gain, efficiency and antenna pattern. Although the test considers the environment (such as the device around the antenna, open and close lid) impact on the antenna performance, it cannot tell the final radiated transmitting power and receiving 57 ModuleANT_MainNCNC0RMainAntenna sensitivity. 4 RF Interface Figure 26. Network analyzer and anechoic chamber You will need: Universal radio communication tester, spectrum analyzer and anechoic chamber. Test items: TRP, TIS and directionality. Antenna system is determined by the whole device, and the antenna is just an important part of the whole device. The antenna performance of the whole device must be concluded by the active test results. The active test evaluates the radiation performance of the device by focusing on the transmitting power and receiving sensitivity. The test measures the transmitting power and receiving sensitivity of the device in all directions in 3D space in specific anechoic chamber, which can directly reflect the radiation performance of the whole device. TRP TRP (Total Radiated Power): the average value of the transmitting power of the entire radiation sphere. It reflects the transmitting power of the whole device, and it is related to the transmitting power and antenna radiation performance of the device in conductive state. 58 4 RF Interface Figure 27. TRP test TIS TIS (Total Isotropic Sensitivity): reflects the receiving sensitivity of the entire radiation sphere. It reflects the reception of the whole device; it is related to the conductive sensitivity and radiation performance of the antenna. Figure 28. TIS test 59 Spectrum AnalyzerUniversal Radio Communication TesterRelay Switch UnitMAPS ControllerPCReceiveAntennaGPIB-BusMobile PhoneTRP testMeasurement Signal PathUniversal Radio Communication TesterRelay Switch UnitMAPS ControllerPCReceiveAntennaGPIB-BusMobile PhoneTIS testMeasurement Signal Path 5 Reliability 5 Reliability 5.1 Temperature and Humidity Requirements Table 35. Environment indicators Indicator Description Temperature and Humidity Indicator Operating temperature:

The module works normally within this temperature range, and the related performance 30 to +75 meets the requirements of 3GPP standards. Extended temperature:

-40 to +85 The module works normally within this temperature range, and the baseband RF function is normal. Some RF indicators may exceed the 3GPP standard. When the temperature returns to the normal working range of the module, all indicators will still meet the 3GPP standard. Storage temperature:

The module application terminal should be stored at a certain temperature. Beyond this range, the

-45 to +90 module may not work properly or be damaged. Humidity range:

095%RH The module works normally within this humidity range, and the related performance meets the requirements of 3GPP standards. In the extended operating temperature range, some RF indexes may exceed the standard. It is suggested that the temperature control measures should be considered in the application end under the harsh environment. 5.2 Reliability Indicators The reliability test is conducted according to the industrial reliability test. The following are 60 5 Reliability the standard test items and test conditions. Table 36. Industrial reliability test Test Item Test Condition High temperature aging High temperature and humidity 85, 168H/504H/1008H 85 , 85%RH, 168H/504H/1008H High and low temperature, high and low humidity, high and low Corner test voltage, six groups of combinations, and each combination runs for 24 hours Temperature shock 90/-45, 200C Random vibration Frequency range: (200 to 2000)Hz, PSD = 0.04 g2/Hz, X/Y/Z axis for 1 hour Monomer drop 1m, 6 sides and 2 wheels Peak acceleration: 180m/s2 Mechanical collision Pulse duration: 6ms Number of collisions: 1000 Low temperature boot

-40; 30 minutes Off/5 minutes Idle; 3 days 3 days (3 cycles):

Condensation Test First and second cycle with cold cycle Third cycle without cold cycle Temperature cycle 85C/-40C; 10C/min; 10min; 240 cycles Sinusoidal vibration Amplitude: 3.0G peak to peak;

Frequency: 5 - 500Hz;

61 5 Reliability Test Item Test Condition Sweep frequency: 0.5 Octave/min, linear;

Each axis: 2H;

Salt spray Neutral salt spray, 48H 5.3 ESD Indicators The module is ESD sensitive component, and the ability to resist static electricity is weak. So ESD precautions that apply to ESD sensitive components should be strictly followed. Proper ESD procedures must be applied throughout the processing, delivery, assembly and operation. The ESD allowable discharge range of the module is as follows (temperature: 25C, relative humidity: 40 %):

Table 37. ESD indicators Test Point Air Discharge (kV) Contact Discharge (kV) Antenna ground 15KV Antenna core

8 8 The data is tested based on the MG661 development board. 62 6 Thermal Design 6 Thermal Design 6.1 Overview The design guidelines provided in this document are general guidelines. There may b e unavoidable differences between different products. When designing a specific interf ace circuit, please pay attention to the specific characteristics of the hardware and so ftware of the module. Before designing the hardware:

Refer to the Pin Definition section for details on the attributes of each pin in the module. Prepare SCH component library and PCB package library. 6.2 Thermal Basis Conductive heat dissipation Conductive heat dissipation refers to the transfer of energy through kinetic energy between molecules of objects when they contact. Heat sink/shell with larger surface area dissipates heat better. The smaller distance between the cooling system and heat source is preferred. Materials with high thermal conductivity are preferred, generally: solid > liquid > gas. Thermal resistance During two solid surfaces contact, the actual contact is only the area of some discrete parts due to limit of the material processing procedure. The gap between the non-contact surfaces is filled with air, and generates a large thermal resistance. Methods of reducing the thermal resistance include increasing contact pressure and increasing materials (thermal conductive silicone) to fill the gap between the surfaces. 63 Thermal convection Convective heat dissipation is an energy exchange in which a fluid flows over a solid surface. Heat sink/shell with larger surface area dissipates heat better. 6 Thermal Design 6.3 Thermal Design 6.3.1 Main Board Recommendations for main board design:

Increase PCB size, and keep the module away from other heat source devices. Figure 29.PCB layout Increase PCB layers and the copper area at each layer. Add adequate paths under and near the module. Plated holes boast better cooling effect than buried holes and blind holes. Vertically stacked paths boast better cooling effect than staggered paths. 64 Heat sourceModuleHeat sourceModuleBad Better 6 Thermal Design Figure 30. PCB stack Figure 31. PCB hole comparison 6.3.2 Product Structure Recommendations for structure design:

Reduce the distance between module and heat sink and shell. Thermal conductive material thickness should not exceed 3 mm. The thermal conduction path is shown in the following figure. Figure 32. Thermal conduction path Use shell material with better thermal conductivity to facilitate cooling. Thermal conductivity sequence: Al > Fe > Plastic. Place the heat sink above the module. 65 ModuleModuleBad BetterCopperDielectricTimShieldTimPartsTimMain boardShellRadiatorgModuleCold airHot air Allow direct contact between the heat sink and thermal conductive material on the module if the heat sink can be exposed to the product surface. Consider convection if the product has cooling holes. 6 Thermal Design 66 7 Structure Specifications 7 Structure Specifications 7.1 Appearance The schematic diagram of MG661 module is as follows:

Figure 33. TOP schematic diagram 67 7 Structure Specifications Figure 34. Bottom schematic diagram 7.2 Dimensions Indicator Weight Package Table 38. Packaging mode Description 1.2g LGA, with 109 pins in total Appearance dimensions

(17.70.15) mm (15.80.15) mm (2.40.2) mm Structure dimensions See the following figure. The following figure shows the structural dimensions. 68 7 Structure Specifications Figure 35. Structural dimensions (top view/side view/bottom view) 69 8 Packaging and Production 8 Packaging and Production 8.1 Packaging The module adopts tape packaging, and the storage, transportation and the usage of module can be protected to the greatest extent. Please read the instructions carefully to avoid damaging the product. The product packaging is divided into three layers:

Outer packaging Hard cartoon box Vacuum packaging Anti-static sealed vacuum bag Inner packaging Tape packaging The module is a precise electronic product, and may be permanently damaged if you do not take correct ESD measures. The module is moisture sensitive, please avoid moistening the product to prevent permanent damage. Each roll is packed with 500 pcs, each box is packed with one roll, and each hard carton box is packed with 4 boxes. Packaging process 70 8 Packaging and Production Figure 36. Tape packaging process Description:

1. Place a module into the carrier tape slot in sequence according to the specified direction, and seal the heat sealing film. 2. Place the specified number of module tapes, as shown in the following figure. 3. Before vacuumizing, place 3 bags of drying agent and a humidity card above the tape, and paste the carrier tape label. 4. Put the whole into a vacuum bag and vacuumizing. 5. The vacuum electrostatic bag is put into a tape white box, and only one electrostatic bag is put into a single white box. Buckle the white box and paste a label. 6. Seal the bottom of the outer box, and put the 4 pcs white boxes into the outer box as shown in the figure. 71 7. Seal the top of the outer box in an I-shape, paste an outer box label in the rectangular frame on the side, and paste a box sealing label on the top and bottom parts of the outer 8 Packaging and Production box respectively. Tape dimensions Tape dimensions:

Figure 37. Carrier tape dimensions Reel dimensions:

72 8 Packaging and Production Figure 38. Reel dimensions 8.2 Storage Storage conditions (recommended): temperature is 235C; relative humidity is 3570%. Storage period (sealed vacuum packaging): 12 months under the recommended storage conditions. 8.3 SMT For module stencils design, solder paste and oven temperature control, see Fibocom_MG661_SMT Application Design. 73 Appendix A Acronyms and Abbreviations Change History Acronym and Abbreviation Description ADC ADP BT CPE DCDC DDR EDGE ESD FDD FEM Analog to Digital Converter Application Development Platform Bluetooth Customer Premises Equipment Direct Current to Direct Current Double Data Rate Enhanced Data rate for GSM Evolution Electronic Static Discharge Frequency Division Duplexing Front End Module GPRS General Packet Radio Service GSM LDO LTE I2C PCB PCM PMU RF RTC Global Standard for Mobile Communications Low Dropout Regulator Long Term Evolution Inter Integrated Circuit Printed Circuit Board Pulse Code Modulation Power Manager Unit Radio Frequency Real Time Clock 74 RMII SDIO SIM SPI TDD UART USB Reduced Media Independent Interface Secure Digital Input and Output Subscriber Identification Module Serial Peripheral Interface Time Division Duplexing Universal Asynchronous Receiver Transmitter Universal Serial Bus WCDMA Wideband Code Division Multiple Access WLAN Wireless Local Area Network Change History 75 Change History Appendix B Reference Standards This product is designed with reference to the following standards:

3GPP TS 51.010-1 V10.5.0: Mobile Station (MS) conformance specification; Part 1:

Conformance specification 3GPP TS 34.121-1 V10.8.0: User Equipment (UE) conformance specification; Radio transmission and reception (FDD); Part 1: Conformance specification 3GPP TS 34.122 V10.1.0: Technical Specification Group Radio Access Network; Radio transmission and reception (TDD) 3GPP TS 36.521-1 V10.6.0: User Equipment (UE) conformance specification; Radio transmission and reception; Part 1: Conformance testing 3GPP TS 21.111 V10.0.0: USIM and IC card requirements 3GPP TS 51.011 V4.15.0: Specification of the Subscriber Identity Module -Mobile Equipment (SIM-ME) interface 3GPP TS 31.102 V10.11.0: Characteristics of the Universal Subscriber Identity Module

(USIM) application 3GPP TS 31.11 V10.16.0: Universal Subscriber Identity Module (USIM) Application Toolkit(USAT) 3GPP TS 36.124 V10.3.0: Electro Magnetic Compatibility (EMC) requirements for mobile terminals and ancillary equipment 3GPP TS 27.007 V10.0.8: AT command set for User Equipment (UE) 3GPP TS 27.005 V10.0.1: Use of Data Terminal Equipment - Data Circuit terminating Equipment (DTE - DCE) interface for Short Message Service (SMS) and Cell Broadcast Service (CBS) 76 Appendix C Reference Documents Change History This product is designed by referring to the following documents:

Fibocom_Design Guide_RF Antenna Fibocom_MC981_ADP_User Guide Fibocom_MC66x/MG66x_AT Commands User Manual Fibocom_MG661_SMT Application Design 77 Change History FCC Conformance information Important Notice to OEM integrators 1. This module is limited to OEM installation ONLY. 2. This module is limited to installation in mobile applications, according to Part 2.1091(b). 3. The separate approval is required for all other operating configurations, including portable configurations with respect to Part 2.1093 and different antenna configurations 4. For FCC Part 15.31 (h) and (k): The host manufacturer is responsible for additional testing to verify compliance as a composite system. When testing the host device for compliance with Part15 Subpart B, the host manufacturer is required to show compliance with Part 15 Subpart B while the transmitter module(s) are installed and operating. The modules should be transmitting and the evaluation should confirm that the module's intentional emissions are compliant (i.e. fundamental and out of band emissions). The host manufacturer must verify that there are no additional unintentional emissions other than what is permitted in Part 15 Subpart B or emissions are complaint with the transmitter(s) rule(s). The Grantee will provide guidance to the host manufacturer for Part 15 B requirements if needed. Important Note notice that any deviation(s) from the defined parameters of the antenna trace, as described by the instructions, require that the host product manufacturer must notify to Fibocom Wireless Inc. that they wish to change the antenna trace design. In this case, a Class II permissive change application is required to be filed by the USI, or the host manufacturer can take responsibility through the change in FCC ID (new application) procedure followed by a Class II permissive change application. End Product Labeling When the module is installed in the host device, the FCC ID label must be visible through a 78 Change History window on the final device or it must be visible when an access panel, door or cover is easily re-moved. If not, a second label must be placed on the outside of the final device that contains the following text: Contains FCC ID:ZMOMG661LA The FCC ID can be used only when all FCC compliance requirements are met. Antenna Installation

(1) The antenna must be installed such that 20 cm is maintained between the antenna and users,

(2) The transmitter module may not be co-located with any other transmitter or antenna.

(3) Only antennas of the same type and with equal or less gains as shown below may be used with this module. Other types of antennas and/or higher gain antennas may require additional authorization for operation. In the event that these conditions cannot be met (for example certain laptop configurations or co-location with another transmitter), then the FCC authorization is no longer considered valid and the FCC ID cannot be used on the final product. In these circumstances, the OEM integrator will be responsible for re-evaluating the end product (including the transmitter) and obtaining a separate FCC authorization. Manual Information to the End User The OEM integrator has to be aware not to provide information to the end user regarding how to install or remove this RF module in the users manual of the end product which integrates this module. The end user manual shall include all required regulatory information/warning as show in this manual. Federal Communication Commission Interference Statement This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation. This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This 79 Change History equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one of the following measures:

- Reorient or relocate the receiving antenna.

- Increase the separation between the equipment and receiver.

- Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.

- Consult the dealer or an experienced radio/TV technician for help. Any changes or modifications not expressly approved by the party responsible for compliance could void the user's authority to operate this equipment. This transmitter must not be co-

located or operating in conjunction with any other antenna or transmitter. List of applicable FCC rules This module has been tested and found to comply with part 22, part 24, part 27, part 15B requirements for Modular Approval. The modular transmitter is only FCC authorized for the specific rule parts (i.e., FCC transmitter rules) listed on the grant, and that the host product manufacturer is responsible for compliance to any other FCC rules that apply to the host not covered by the modular transmitter grant of certification. If the grantee markets their product as being Part 15 Subpart B compliant (when it also contains unintentional-radiator digital circuity), then the grantee shall provide a notice stating that the final host product still requires Part 15 Subpart B compliance testing with the modular transmitter installed. 80 Change History This device is intended only for OEM integrators under the following conditions: (For module device use) 1) The antenna must be installed such that 20 cm is maintained between the antenna and users, and 2) The transmitter module may not be co-located with any other transmitter or antenna. As long as 2 conditions above are met, further transmitter test will not be required. However, the OEM integrator is still responsible for testing their end-product for any additional compliance requirements required with this module installed. Radiation Exposure Statement This equipment complies with FCC radiation exposure limits set forth for an uncontrolled environment. This equipment should be installed and operated with minimum distance 20 cm between the radiator & your body. 81 Requirement per KDB996369 D03 Change History 2.2 List of applicable FCC rules List the FCC rules that are applicable to the modular transmitter. These are the rules that specifically establish the bands of operation, the power, spurious emissions, and operating fundamental frequencies. DO NOT list compliance to unintentional-radiator rules (Part 15 Subpart B) since that is not a condition of a module grant that is extended to a host manufacturer. See also Section 2.10 below concerning the need to notify host manufacturers that further testing is required.3 Explanation: This module meets the requirements of part 22, part 24, part 27 2.3 Summarize the specific operational use conditions Describe use conditions that are applicable to the modular transmitter, including for example any limits on antennas, etc. For example, if point-to-point antennas are used that require reduction in power or compensation for cable loss, then this information must be in the instructions. If the use condition limitations extend to professional users, then instructions must state that this information also extends to the host manufacturers instruction manual. In addition, certain information may also be needed, such as peak gain per frequency band and minimum gain, specifically for master devices in 5 GHz DFS bands. Explanation: The EUT has a Rubber Duck Antenna, and the antenna use a replaceable antenna 82 Change History 2.4 Limited module procedures If a modular transmitter is approved as a limited module, then the module manufacturer is responsible for approving the host environment that the limited module is used with. The manufacturer of a limited module must describe, both in the filing and in the installation instructions, the alternative means that the limited module manufacturer uses to verify that the host meets the necessary requirements to satisfy the module limiting conditions. A limited module manufacturer has the flexibility to define its alternative method to address the conditions that limit the initial approval, such as: shielding, minimum signaling amplitude, buffered modulation/data inputs, or power supply regulation. The alternative method could include that the limited module manufacturer reviews detailed test data or host designs prior to giving the host manufacturer approval. This limited module procedure is also applicable for RF exposure evaluation when it is necessary to demonstrate compliance in a specific host. The module manufacturer must state how control of the product into which the modular transmitter will be installed will be maintained such that full compliance of the product is always ensured. For additional hosts other than the specific host originally granted with a limited module, a Class II permissive change is required on the module grant to register the additional host as a specific host also approved with the module. Explanation: The module is not a limited module. 2.5 Trace antenna designs For a modular transmitter with trace antenna designs, see the guidance in Question 11 of KDB Publication 996369 D02 FAQ Modules for Micro-Strip Antennas and traces. The integration information shall include for the TCB review the integration instructions for the following aspects:

layout of trace design, parts list (BOM), antenna, connectors, and isolation requirements. a) Information that includes permitted variances (e.g., trace boundary limits, thickness, length, width, shape(s), 83 Change History dielectric constant, and impedance as applicable for each type of antenna);

b) Each design shall be considered a different type (e.g., antenna length in multiple(s) of frequency, the wavelength, and antenna shape (traces in phase) can affect antenna gain and must be considered);

c) The parameters shall be provided in a manner permitting host manufacturers to design the printed circuit (PC) board layout;

d) Appropriate parts by manufacturer and specifications;

e) Test procedures for design verification; and f) Production test procedures for ensuring compliance. The module grantee shall provide a notice that any deviation(s) from the defined parameters of the antenna trace, as described by the instructions, require that the host product manufacturer must notify the module grantee that they wish to change the antenna trace design. In this case, a Class II permissive change application is required to be filed by the grantee, or the host manufacturer can take responsibility through the change in FCC ID (new application) procedure followed by a Class II permissive change application. Explanation: Yes, The module with trace antenna designs, and This manual has been shown the layout of trace design, antenna, connectors, and isolation requirements. 2.6 RF exposure considerations It is essential for module grantees to clearly and explicitly state the RF exposure conditions that permit a host product manufacturer to use the module. Two types of instructions are required for RF exposure information: (1) to the host product manufacturer, to define the application conditions (mobile, portable xx cm from a persons body); and (2) additional text 84 Change History needed for the host product manufacturer to provide to end users in their end-product manuals. If RF exposure statements and use conditions are not provided, then the host product manufacturer is required to take responsibility of the module through a change in FCC ID (new application). Explanation: This module complies with FCC RF radiation exposure limits set forth for an uncontrolled environment, This equipment should be installed and operated with a minimum distance of 20 centimeters between the radiator and your body." This module is designed to comply with the FCC statement, FCC ID is: ZMOMG661LA 2.7 Antennas A list of antennas included in the application for certification must be provided in the instructions. For modular transmitters approved as limited modules, all applicable professional installer instructions must be included as part of the information to the host product manufacturer. The antenna list shall also identify the antenna types (monopole, PIFA, dipole, antenna gain etc. (note that for example an omni-directional antenna is not considered to be a specific antenna type)). For situations where the host product manufacturer is responsible for an external connector, for example with an RF pin and antenna trace design, the integration instructions shall inform the installer that unique antenna connector must be used on the Part 15 authorized transmitters used in the host product. The module manufacturers shall provide a list of acceptable unique connectors. Explanation: The EUT has a Rubber Duck Antenna, and allow maximum antenna gain as below:

LTE band 2 1.93 dBi LTE band 4 2.86 dBi LTE band 5 1.32 dBi LTE band 7 1.07 dBi LTE band 66 3.53 dBi 85 Change History 2.8 Label and compliance information Grantees are responsible for the continued compliance of their modules to the FCC rules. This includes advising host product manufacturers that they need to provide a physical or e-

label stating Contains FCC ID with their finished product. See Guidelines for Labeling and User Information for RF Devices KDB Publication 784748. Explanation: The host system using this module, should have label in a visible area indicated the following texts: Contains FCC ID: ZMOMG661LA 2.9 Information on test modes and additional testing requirements5 Additional guidance for testing host products is given in KDB Publication 996369 D04 Module Integration Guide. Test modes should take into consideration different operational conditions for a stand-alone modular transmitter in a host, as well as for multiple simultaneously transmitting modules or other transmitters in a host product. The grantee should provide information on how to configure test modes for host product evaluation for different operational conditions for a stand-alone modular transmitter in a host, versus with multiple, simultaneously transmitting modules or other transmitters in a host. Grantees can increase the utility of their modular transmitters by providing special means, modes, or instructions that simulates or characterizes a connection by enabling a transmitter. This can greatly simplify a host manufacturers determination that a module as installed in a host complies with FCC requirements. Explanation: Top band can increase the utility of our modular transmitters by providing instructions that simulates or characterizes a connection by enabling a transmitter. 86 Change History 2.10 Additional testing, Part 15 Subpart B disclaimer The grantee should include a statement that the modular transmitter is only FCC authorized for the specific rule parts (i.e., FCC transmitter rules) listed on the grant, and that the host product manufacturer is responsible for compliance to any other FCC rules that apply to the host not covered by the modular transmitter grant of certification. If the grantee markets their product as being Part 15 Subpart B compliant (when it also contains unintentional-radiator digital circuity), then the grantee shall provide a notice stating that the final host product still requires Part 15 Subpart B compliance testing with the modular transmitter installed. Explanation: The module has evaluated by FCC Part 15 Subpart B. The host should be evaluated by the FCC Subpart B. 87

( CO FIDCCON MG661-LA S/N:XXXXXXXXXX IMEI 14 XXXXXXXXXXXXXXK IMEI2:XXXXXXXXXXXXXXX FCC ID:ZMOMG661LA IMEI1;IMEI2;S 6*6 19 iO Fipccom

|| MG661-LA S/N:XXXXXXXKXX TI MIE 1 DOGOCOOOOOOOOX IME 12 XXXOXOOOXXKKKXK FCC ID:ZMOMG661LA IMEI IMEI2;

WARNING:pdfminer.pdfpage:The PDF <_io.BufferedReader name='/Volumes/Scratch/Incoming/eg-scratch/6734889.pdf'> contains a metadata field indicating that it should not allow text extraction. Ignoring this field and proceeding. Use the check_extractable if you want to raise an error in this case lucy.liu 1101,Tower A, Building 6, Shenzhen International, Innovation Valley, Dashi 1st Rd, Nanshan, Fibocom Wireless Inc. ShenZhen, China Tel: +8675526733555 ; Fax: +86-755-26520841 Federal Communications Commission 7435 Oakland Mills Road Columbia MD 21046 Subject: Certification designating a U.S. agent for service of process pursuant to Part 2.911(d)(7) To whom it may concern,

[Fibocom Wireless Inc. Grantee Code ZMO] (the applicant) certifies that, as of the date of the filing of application, [Fibocom Wireless USA] (the agent) is designated as the U.S. agent for the purpose of accepting service of process on behalf of the applicant. The information of agent are:

U.S. Agent: Fibocom Wireless USA FCC Registration Number (FRN): 0033437914 Physical U.S. address: 5909 Peachtree Dunwoody Rd Ste 910 Atlanta, GA 30328 United States Contact: Lei Yao Phone: +01 (469)463-6983 Email: Lei.yao@fibocom.com The applicant accepts to maintain an agent for service of process in the United States for no less than one year after either the grantee has permanently terminated all marketing and importation of the applicable equipment within the U.S., or the conclusion of any Commission-related administrative or judicial proceeding involving the equipment, whichever is later. The agent accepts the designation by (the applicant) as the U.S. agent to accept service of process includes, but is not limited to, delivery of any correspondence, notices, orders, decisions, and requirements of administrative, legal, or judicial process related to Commission proceedings. Signed by the Applicant Signed by the Agent Name: Patrick Ma Email:

lucy.liu@fibocom.com Date: April 21, 2023 Name: Lei Yao Email: Lei.yao@fibocom.com Date: April 21, 2023

Fibocom Wireless Inc Federal Communications Commission Authorization and Evaluation Division 7435 Oakland Mills Road Columbia, MD 21046 USA Date:2023/8/1 Ref: Attestation Statements Part 2.911(d)(5)(i) Filing FCC ID: ZMOMG661LA Fibocom Wireless Inc. certifies that the equipment for which authorization is sought is not covered equipment prohibited from receiving an equipment authorization pursuant to section 2.903 of the FCC rules. Sincerely,

(Applicant signature) Print name: Patrick Ma Rev 1/26/2023

Fibocom Wireless Inc Federal Communications Commission Authorization and Evaluation Division 7435 Oakland Mills Road Columbia, MD 21046 USA Date: 2023/8/1 Ref: Attestation Statements Part 2.911(d)(5)(ii) Filing FCC ID: ZMOMG661LA Fibocom Wireless Inc. certifies that, as of the date of the filing of the application, the applicant is not identified on the Covered List as an entity producing covered equipment. Sincerely,

(Applicant signature) Print name: Patrick Ma Rev 1/26/2023

Fibocom Wireless Inc Agent Authorization Company: Fibocom Wireless Inc Address: 1101, Tower A, Building 6, Shenzhen International Innovation Valley, Dashi 1st Rd, Nanshan, Shenzhen, China Product Name: LTE Module Model Number(s): MG661-LA Product Description: LTE Module We authorize MiCOM Labs Inc., 575 Boulder Court, Pleasanton, California 94566, USA, to act on our behalf on all matters concerning the certification of above named equipment. We declare that MiCOM Labs Inc. is allowed to forward all information related to the approval and certification of equipment to the regulatory agencies as required and to discuss any issues concerning the approval application. Any and all acts carried out by MiCOM Labs on our behalf shall have the same effect as acts of our own. Signature:

Name:

Patrick Ma Title:

Manager Company: Fibocom Wireless Inc Date: 2023-08-03

WARNING:pdfminer.pdfpage:The PDF <_io.BufferedReader name='/Volumes/Scratch/Incoming/eg-scratch/6734999.pdf'> contains a metadata field indicating that it should not allow text extraction. Ignoring this field and proceeding. Use the check_extractable if you want to raise an error in this case Modular Approval Request FCC (KDB 996369 D01 & Part 15.212) FCC ID: ZMOMG661LA Items to be covered by Single modular transmitters. 1. The modular transmitter must have its own RF shielding. 2. The modular transmitter must have buffered modulation/data inputs (if such inputs are provided) to ensure that the module will comply with Part 15 requirements under conditions of excessive data rates or over-modulation. Answer from applicant Yes, please see exhibition external photos Yes, The modular has buffer modulation /data inputs 3. The modular transmitter must have its own power supply regulation. Yes, please see the schem.pdf 4. The modular transmitter must comply with the antenna requirements of Section 15.203 and 15.204(b)(c). The antenna must either be permanently attached or employ a unique antenna coupler (at all connections between the module and the antenna, including the cable). 5. The modular transmitter must be tested in a stand-alone configuration, i.e., the module must not be inside another device during testing. This is intended to demonstrate that the module is capable of complying with Part 15 emission limits regardless of the device into which it is eventually installed. 6. The modular transmitter must be equipped with either a permanently affixed label or must be capable of electronically displaying its FCC identification number in accordance with 15.212 (a)(1)(vi)(A) / (B). 7. The modular transmitter must comply with any specific rule or operating requirements applicable to the transmitter and the manufacturer must provide adequate instructions along with the module to explain any such requirements. A copy of these instructions must be included in the application for equipment authorization. For example, there are very strict operational and timing requirements that must be met before a transmitter is authorized for operation under Section 15.231. For instance, data transmission is prohibited, except for operation under Section 15.231(e), in which case there are separate field strength level and timing requirements. Compliance with these requirements must be assured. 8. The modular transmitter must comply with any applicable RF exposure requirements. For example, FCC Rules in Sections 1.1310, 2.1091, 2.1093, and specific Sections of Part 15, including 15.319(i), 15.407(f), 15.253(f) and 15.255(g), require that Unlicensed PCS, UNII and millimeter wave devices perform routine environmental evaluation for RF Exposure to demonstrate compliance. In addition, spread spectrum transmitters operating under Section 15.247 are required to address RF Exposure compliance. Modular transmitters approved under other Sections of Part 15, when necessary, may also need to address certain RF Exposure concerns, typically by providing specific installation and operating instructions for users, installers and other interested parties to ensure compliance. Yes, The requirements of antenna connector and spurious emission have been fulfilled. Please refer to the test report exhibition. Yes, Please refer to the setup photo exhibition for the stand-alone configuration Yes, The Module will be label with its own FCC ID ,and the instruction on the labelling rule of the end product has been stated in the user manual of this module .please refer to the label and user manual exhibition. Yes, The required FCC rule has been fulfilled and all the instruction for maintaining compliance have been clearly stated in the user manual. Yes, Please refer exhibition RF exposure for the compliance of MPE RF exposure rule. Items to be covered by Split modular transmitters. 1. The modular transmitter must comply with all requirements of a single modular transmitter except for items (1) & (5) of the above single modular approval requirements. Answer from applicant 2. Only the radio front end must be shielded. The physical crystal and tuning capacitors may be located external to the shielded radio elements. The interface between the split sections of the modular system must be digital with a minimum signalling amplitude of 150 mV peak-to-peak. 3. Control information and other data may be exchanged between the transmitter control elements and radio front end. 4. The sections of a split modular transmitter must be tested installed in a host device(s) similar to that which is representative of the platform(s) intended for use. 5. Manufacturers must ensure that only transmitter control elements and radio front end components that have been approved together are capable of operating together. The transmitter module must not operate unless it has verified that the installed transmitter control elements and radio front end have been authorized together. Manufacturers may use means including, but not limited to, coding in hardware and electronic signatures in software to meet these requirements, and must describe the methods in their application for equipment authorization. Note: A limited modular approval (LMA) may be granted for single or split modular transmitters that comply partially with the requirements above. Name and surname of applicant (or authorized representative): Patrick Ma Date: _2023/8/1 Signature:

WARNING:pdfminer.pdfpage:The PDF <_io.BufferedReader name='/Volumes/Scratch/Incoming/eg-scratch/6734921.pdf'> contains a metadata field indicating that it should not allow text extraction. Ignoring this field and proceeding. Use the check_extractable if you want to raise an error in this case Fibocom Wireless Inc Date: 2023/8/1 To:

Federal Communications Commission, Authorization & Evaluation Division, 7435 Oakland Mills Road, Columbia, MD 21046 RE: Fibocom Wireless Inc FCC ID: ZMOMG661LA FCC Certification Confidentiality Request Gentlemen:

This letter is to comply with 47 CFR 0.457 and 0.459 pertaining to confidentiality material. Fibocom Wireless Inc requests that the following documents regarding this submission for FCC ID:

ZMOMG661LA be kept Long-Term confidential:

Exhibit Type Block Diagram Schematics Operational Description Operational Description.pdf Part list Tune up Tune up.pdf File Name Block Diagram.pdf Schematics.pdf BOM.pdf Those documents contain detailed system and equipment description and related information about the product which Fibocom Wireless Inc considers to be confidential proprietary, a custom design and, otherwise, not releasable to the general public. Since this design is a basis form which future technological products will evolve, Fibocom Wireless Inc considers this information would be of benefit to its competitors, and that the disclosure of the information in these documents would give competitors an unfair advantage in the market. Thank you for your attention to this matter. Yours Sincerely, Print name: Patrick Ma Title: Certification Director Signature:

Fibocom Wireless Inc