M10 GSM Module User Manual

M10 User Manual M10 User Manual Contents Contents ........................................................................................................................... 1 0. Revision history ............................................................................................................. 4 1. Introduction ................................................................................................................... 5 1.1. Reference ............................................................................................................. 5 2. Product Concept............................................................................................................. 6 3. Placement...................................................................................................................... 8 3.1. Pin Assignment ..................................................................................................... 8 3.2. Placement recommendation................................................................................... 15 3.3. Placement clearance ............................................................................................. 15 4. Digital I/O Connection .................................................................................................. 17 5. VDD_EXT Pin ............................................................................................................ 18 6. Serial Interface and Debug Interface ............................................................................... 19 7. SIM Card .................................................................................................................... 20 8. SLEEP Mode ............................................................................................................... 21 9. Audio Trace................................................................................................................. 22 10. RF Design Guide ........................................................................................................ 23 10.1. Recommended Impedance Matching Circuit.......................................................... 23 10.2. Matched RF Transmission Line Design ................................................................. 24 10.3. PCB Layout Consideration .................................................................................. 24 11. The Recommended Ramp-soak-spike Reflow Profile ...................................................... 28 M10 User Manual Table Index TABLE 2: DIGITAL I/ O ELECTRICAL CHARA CTERISTICS.................................................................. 17 M10 User Manual Figure Index FIGURE 1: PIN ASSIGNM ENT ........................................................................................................................... 9 FIGURE 2: RECOMM ENDATION OF PLA CEM ENT ................................................................................. 15 FIGURE 3: PLACEMENT CLEARANCE ................................................................................................... 16 FIGURE 4: CIRCUIT OF THE SIM CARD ............................................................................................... 20 FIGURE 5: A UDIO TRACE ROUTING EXAMPLE ..................................................................................... 22 FIGURE 6: T-TYPE MATCHING CIRCUIT.................................................................................................... 23 FIGURE 7: -TYPE MATCHING CIRCUIT................................................................................................... 23 FIGURE 8: M 10 RF_ANT PCB LAYOUT ....................................................................................................... 24 FIGURE 9: REFERENCE PCB DESIGN WITH ANTENNA PAD IN A FOUR-LAYER PCB ............. 26 FIGURE 10: REFERENCE PCB DESIGN WITH RF CONNECTOR IN A FOUR-LAYER PCB ........ 27 FIGURE 11: STACK-UP OF THE FOUR-LAYER PCB................................................................................ 27 FIGURE 12: THE RECOMM ENDED RAMP-SOAK-SPIKE REFLOW P ROFILE............................... 28 M10 User Manual 0. Revision history Revision Date 1.00 Author Ken Ji/

Samuel Hong Description of change Origin 1. Introduction This document gives recommendation for M10 module integration in a wireless application, such as vehicle tracking system, smart metering and PDA. It gives some recommendations for design notes, reference circuit and PCB layout. The M10 is a Quad-band GSM/GPRS engine that works at frequencies of GSM850, and PCS1900. M10 features GPRS and supports the GPRS coding schemes CS-1, CS-2, CS-3 and CS-4. With a tiny profile of 29mm 29mm 3.6 mm, the module can meet almost all the requirements for M2M applications, including Tracking and Tracing, Intelligent Instrument, Wireless POS, Security, Telematics, Remote Controlling, etc. M10 is an SMD type module, which can be embedded in customer application through its 64-pin pads. It provides all hardware interfaces between the module and customers host board. 1.1. Reference 2. Product Concept The M10 is a Quad-band GSM/GPRS engine that works at frequency bands of GSM850 and PCS 1900. The M10 features GPRS multi-slot class 12 and supports the GPRS coding schemes CS-1, CS-2, CS-3 and CS-4. The M10 is an SMD type module with 64-pin pads and a tiny profile of 29mm x 29mm x 3.6 mm

(the thickness of PCB is 1.6mm), which can fit into almost all customers applications. It provides all hardware interfaces between the module and customer host board. External controller can communicate with M10 through its main UART port. Two audio channels include two microphone inputs and two speaker outputs, which can be easily configured by AT command. The module is designed with power saving technique so that the current consumption could be very low. TCP/IP protocol stack has been integrated in the module. Moreover, extended TCP/IP AT commands have been developed for customer to use the internal TCP/IP protocol easily, which is very useful for data transfer application. The module is fully RoHS compliant to EU regulation. Mechanical dimensions of module 3. Placement Please pay attention to the placement and the PCB layout in your application design. 3.1. Pin Assignment The pin assignment of the M10 module is show n in Figure 1. Placement of module should be carefully considered to make the RF_IN pad as close as possible to antenna so as to reduce overall RF trace length. The longer the RF trace to antenna, the larger the RF insertion loss. In addition, please keep RF part and antenna from the system crystal and the audio part in host board as far as possible to reduce possible RF interference due to GSM transmission bursts from antenna and RF trace. M10 module include the following major functional parts:

The GSM baseband part Flash and SRAM The GSM radio frequency part The SMT pads interface LCD interface SIM card interface Audio interface Key-board interface UART interface Power supply RF interface Figure 1: Pin assignment 3.2. Placement recommendation The analog part components such as microphone should be placed far away from antenna and power supply. General placement recommendation is shown in Figure 2. Figure 2: Recommendation of placement 3.3. Placement clearance The module mounts with 64 SMT pads. For easy maintenance of this module and accessing to these pads, please keep a distance no less than 3mm between M10 and other components. Power SupplyModuleLCD InterfaceSIM InterfacePwrkey&Audio InterfaceKeypad InterfaceUART InterfacePowerAntennaAudio PartKeypad PartDigital Part & Other PartRF Figure 3: Placement clearance 4. Digital I/O Connection If the voltage level of peripheral interface circuit does not match module interface, the power consumption of the system could increase, and could even cause the module damaged. Each digital I/O of the module operates in a 2.8V logic level inside the module. The voltage level of those digital interfaces connected to the module should match the electrical characteristics of the module listed in Table 2. Otherwise, a level shifter circuit must be inserted between the host and the module. Table 1: Digital I/O electrical characteristics SYMBOL MIN VIL VIH VOL VOH 0 1.7 0 2.0 MAX 0.67 3.1 0.34 2.8 UNITS V V V V For direct connection between I/Os, please pay attention to I/Os input or output configuration. If the I/O direction configuration conflicts with each other, the power consumption could increase, and the module could be very hot, and even be damaged. For example, it is forbidden that users I/O outputs a low level while modules connected I/O outputs a high level. 5. VDD_EXT Pin This pin is a power supply from a regulator inside the module which can supply current of about 20mA. Customer can also use this pin to judge whether the module is off or not. When the module is turned off, the VDD_EXT pin will change from high level to low level. 6. Serial Interface and Debug Interface The TXD and RXD pins should be connected to host MCU. The DTR pin should be controlled to trigger SLEEP mode or wakeup the module. The RTS and CTS pins should be connected to the host MCU if hardware flow control is required. The TXD, RXD, PWRKEY and GND pins can also be used for software upgrade and high-level acoustic parameters configuration. The DBG_TXD and DBG_RXD pins are only used for software debug. Please note that the PWRKEY pin should be pulled to low level when the M10 is being upgraded. For more detailed information on serial port design, please refer to document [2]

Notes: Its recommended to connect the pins necessary for firmware upgrade to external interface. 7. SIM Card As shown in Figure 4, connecting a large volume capacitor such as 10uF in the SIM_VDD line could lead to failure of detecting the SIM card. A capacitor between 100nF and 1uF is recommended. Figure 4: Circuit of the SIM card 8. SLEEP Mode The command AT+CSCLK can enable or disable SLEEP mode. When the SLEEP mode is enabled, pulling the DTR pin to high level would drive the module into SLEEP mode; and pulling the DTR pin to low level the module would exit from SLEEP mode. 9. Audio Trace If possible, the audio trace should be placed in inner layer, and shielded by ground in the same layer and the upper and lower adjacent layers to prevent from RF interference. In addition, it is recommended to add as many via as possible between ground layers so as to reduce RF noise. The AGND signal is usually used for AOUT2 channel to establish a single-end output with SPK2P. Do not pair GND with SPK2P to establish an audio output, otherwise TDD (Time Division Duplex) noise from power supply could occur in AOUT2. Figure 5: Audio trace routing example 10. RF Design Guide Correct RF design is essential for RF performance such as transmitting power, receiving sensitivity and harmonics. Following this RF design guide could benefit to improve the RF performance of customers product. 10.1. Recommended Impedance Matching Circuit The impedance of M10s RF_ANT port is 50. If the impedance of antenna is close to 50 in all working frequency bands, the antenna could be connected to the RF_ANT port directly via 50 transmission line. But if the impedance of antenna is not close to 50, a T-type or -type matching circuit should be inserted between transmission line and antenna. The matching components should be placed as close as possible to the antennas feed point. Figure 6 and Figure 7 show the reference designs of T-type and -type matching circuits. Figure 6: T-type matching circuit Figure 7: -type matching circuit NOTE: The impedance of traces in Bold type must be 50. 10.2. Matched RF Transmission Line Design In PCB layout, a matched RF transmission line has a fixed characteristic impedance, which is called Z0, from its source to its load. The source should have an internal resistance of Z0 and the resistance of matching load should close to Z0. Since the impedance of M10s RF_ANT port is 50, the impedance of the RF transmission line from this port to the antenna or the matching circuit should also be made to 50. More than twelve different types of transmission line can be created on a PCB s imply by controlling trace geometry, and some of them are shown in Figure 8. Figure 8: M10 RF_ANT PCB layout Customer may adopt one or certain types of them to design RF trace. Upon the demand of application design, the number of PCB layer can be different such as two and four. Each type of PCB has corresponding stack-up. The stack-up is the name given to the order of the various etched copper foil and dielectric layers that are laminated together under pressure and heat to make a PCB. 10.3. PCB Layout Consideration PCB Layout is essential to the performance of customers product. Here are some rules that should be followed:

Impedance control Control the impedance of RF trace as close as possible to 50. If the thickness between RF_ANT pad and the ground layer is less than 0.4mm, it could significantly decrease the output power. Therefore, when they are too close, we strongly suggest removing the copper in the layer beneath the RF_ANT pad. If RF trace routes to another layer, add GND via along with it to keep GND integral. The clearance between RF trace and ground plane in same layer should be at least twice the RF trace width. Make RF trace as short as possible Place the module and the matching circuit near the antenna pad. Shorten the length of RF trace. Place the antenna PAD in the corner or at the edge of host board. Protect RF trace Avoid placing noise generating traces such as digital signal or clock line near RF trace in the same layer. Carefully route other traces in the layers adjacent to the RF trace, remember not to route in parallel with the RF trace. If possible, keep those traces far away from the RF trace. An RF test point is located at the bottom side of M10 for manufacture purpose. The copper which is close to this test point in the top layer of customers host board must be kept out or removed. No signal trace should be placed in the top layer and the second layer beneath this test point. Insert a picture. Customer can use either antenna PAD or RF connector to connect the antenna. If antenna PAD is adopted, Figure 9 is a reference design for a four-layer PCB. Make the space on all layers beneath antenna pad keep-out. Place a ground PAD near the antenna PAD. The distance between GND PAD and antenna PAD can be around 1.8mm. The size of antenna PAD can be 1.8mm*1.8mm, and the GND PAD should be a little bigger, e.g. 2.5mm*2.5mm. Add several GND via near or on the GND PAD to reduce impedance from the GND PAD to the RF reference ground. Figure 9: Reference PCB design w ith antenna pad in a four-layer PCB If RF connector is adopted, place the RF connector close to module RF_ANT, and add several ground via close to the GND PAD of RF connector. Figure 10 is the reference PCB design. Layer3L2 under ANT PADL2 under RF PADL3 under ANT PADLayer2Layer4L4 under ANT PADLayer1Under RF TEST pointRF PADANT PADGND PADMatching Figure 10: Reference PCB design w ith RF connector in a four-layer PCB The stack-up of the four-layer PCB is shown in Figure 11. Figure 11: Stack-up of the four-layer PCB Layer2Layer4Layer1Layer3MatchingRF connectorUnder RF TEST pointRF PADUnder RF connectorUnder RF PAD 11. The Recommended Ramp-soak-spike Reflow Profile Figure 12: The recommended ramp-soak-spike reflow p rofile FCC Statement Any Changes or modifications not expressly approved by the party responsible for compliance could void the users authority to operate the equipment. FCC RF 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 20cm between the radiator& your body.This transmitter must not be co-located or operating in conjunction with any other antenna or transmitter. FCC Label Instructions The outside of final products that contains this module device must display a label referring to the enclosed module. This exterior label can use wording such as: Contains Transmitter Module FCC ID: YQD-M10" or Contains FCC ID: YQD-M10 Any similar wording that expresses the same meaning may be used.