LM746 Bluetooth Dual Mode Audio Module Standalone (With Embedded Bluetooth 5 Compliant Stack) Product Part No Revised LM746 See Last Page 18/APR/2018 2.3mm m 2 3.9 m 16mm Features F Bluetooth 5 Compliant Low Power Consumption IC Antenna Onboard Partial - SPP & GATT-Based Proles HSP, HFP, A2DP and AVRCP Audio Proles Application Firmware Support Integrated 16-bit Stereo Audio CODEC SBC, MP3 and AAC decoder aptX codec (including support for SCMS-T) and Faststream codec CSRs cVc noise-cancellation technology I2S, PCM and SPDIF Audio Interfaces UART and USB 2.0 (Full Speed) Serial Interfaces 6 Capacitive touch sensor input interfaces 8 digital and 2 analogue I/O Microphone input and Speaker output interfaces 23.9mm x 16mm x 2.3mm SMT Side and Bottom Pads for easy production See our website for this products certications. RoHS, REACH and WEEE Typical Applications Wireless Headphones and Speakers Hand-free Headsets Automotive Infotainment systems Home Entertainment Devices Individual PWM blocks (3 on dedicated LED pads) Audio Adapters. Overview The LM746 Bluetooth Dual Mode audio module is an extremely versatile and cost effective solution. Enabling audio data to be wireless-
ly communicated between audio devices. Using a Bluetooth v2.0, v2.1 and Bluetooth v4.0, v4.1, 5 connection. Its sound enhancement features, makes it a perfect t within your premium audio device. The sound enhancement features includes CSRs aptX audio technol-
ogy. Providing CD-like quality over a Bluetooth connection. And CSRs cVc audio technology for noise cancellation. Perfectly suited to wireless headphones, speakers and hand-free headsets. This standalone module allows the developer to connect a microphone, speakers, capacitive touch sensors and other I/O devices. Running the user application without using an external MCU. LM offer application support to the developer and can create new user applications for the module. Your developed user application and settings can be preloaded to the LM746, simplifying the manufacturing and testing process. Its SMT side and bottom pads allows for easy integrations into your embedded system. LM746 Page 1 of 21
+44(0) 207 428 2647 | sales@lm-technologies.com LM746 Bluetooth Dual Mode Audio Module Standalone (With Embedded Bluetooth 5 Compliant Stack) Product Part No LM746 See Last Page General Specication Wireless Bluetooth Standard 5 Compliant (Dual Mode) Module Type Proles Hardware Chipset Antenna Microcontroller (MCU) Flash Memory RAM Program Interface Interfaces Audio Interfaces Power Supply Power Supply Crystal Oscillators Development Kit Development Kit RF Characteristics Tx Output Power Rx Sensitivity Data Rate Frequency Physical Characteristics Operating Temperature Storage Temperature Dimensions (L x W x H) Weight Certications Compliance Standalone (Congurable with AT Commands) HSP, HFP, A2DP, AVRCP, Partial-SPP and GATT-Based Qualcomm IC Antenna Onboard 16-bit RISC 80 MHz MCU 16 Mbit 56 KB SPI UART, PWM, USB 2.0 (Full Speed), PIO and AIO I2S, PCM and SPDIF 3V3 (VBAT) or 5V (VCHG) 3V3 (VBAT) or 5V (VCHG) 26 MHz LM558 LM558 2 dBm (Bluetooth v2.0, v.2.1)
-90 dBm (Bluetooth v2.0, v.2.1) Up to 3Mbps 2.4 GHz to 2.485 GHz
-20C to +75C
-40C to +85C 23.9mm x 16mm x 2.3mm 1.38g +/- 0.25g tolerance See our website for this products certications. RoHS, REACH and WEEE LM746 Page 2 of 21
+44(0) 207 428 2647 | sales@lm-technologies.com LM746 Bluetooth Dual Mode Audio Module Standalone (With Embedded Bluetooth 5 Compliant Stack) Product Part No LM746 See Last Page 36 35 21 20 Pin Outs 55 Pin 1 Pin Assignments Pin Name 1 2 2 3 4 4 5 6 6 7 8 8 9 GND AIO1 AIO1 AIO0 CAP_SENSE_0 CAP_SENSE_0 CAP_SENSE_1 CAP_SENSE_2 CAP_SENSE_2 CAP_SENSE_3 CAP_SENSE_4 CAP_SENSE_4 CAP_SENSE_5 Type Ground Bi-directional Bi-directional Bi-directional Analogue Analogue Analogue Analogue Analogue Analogue Analogue Analogue Analogue Supply Domain 0V VDD_AUX (1.35V) VDD_AUX (1.35V) VDD_AUX (1.35V) Description Common Ground Analogue input/output Analogue input/output Analogue input/output VDD_AUDIO_DRV (1V8_SMPS) VDD_AUDIO_DRV (1V8_SMPS) Capacitive touch sensor input Capacitive touch sensor input VDD_AUDIO_DRV (1V8_SMPS) Capacitive touch sensor input VDD_AUDIO_DRV (1V8_SMPS) VDD_AUDIO_DRV (1V8_SMPS) Capacitive touch sensor input Capacitive touch sensor input VDD_AUDIO_DRV (1V8_SMPS) Capacitive touch sensor input VDD_AUDIO_DRV (1V8_SMPS) VDD_AUDIO_DRV (1V8_SMPS) Capacitive touch sensor input Capacitive touch sensor input VDD_AUDIO_DRV (1V8_SMPS) Capacitive touch sensor input 10 SD_IN & SPDIF_IN 10 SD_IN & SPDIF_IN Bi-directional with weak pull-down Bi-directional with weak pull-down PIO_POWER PIO_POWER 11 SD_OUT & SPDIF_OUT Bi-directional with weak pull-down PIO_POWER 12 WS 12 WS 13 SCK Bi-directional with weak pull-down Bi-directional with weak pull-down PIO_POWER PIO_POWER Bi-directional with weak pull-down PIO_POWER I2S Interface & SPDIF Interface I2S Interface & SPDIF Interface Sync data output. Alt PIO_17 Sync data output. Alt PIO_17 I2S Interface & SPDIF Interface Sync data output. Alt PIO_18 I2S Interface & SPDIF Interface I2S Interface & SPDIF Interface Sync data output. Alt PIO_19 Sync data output. Alt PIO_19 I2S Interface & SPDIF Interface Sync data output. Alt PIO_20 14 SPI_CLK 14 SPI_CLK Input with strong pull-down Input with strong pull-down PIO_POWER PIO_POWER SPI clock SPI clock 15 16 17 18 19 SPI_MOSI SPI_MISO SPI_CS#
RESET UART_RX 20 GND 21 UART_TX 22 LED0 LM746 Page 3 of 21 Input with weak pull-down Output with strong pull-up Input with weak pull-down Input with strong pull-up Bi-directional strong pull-up Ground Bi-directional weak pull-up Open drain output PIO_POWER PIO_POWER PIO_POWER PIO_POWER PIO_POWER 0V PIO_POWER PIO_POWER Master out slave in (SPI) Master in slave out (SPI) Chip select for SPI, active low Reset if low. Pull low for minimum 5ms for reset. UART data input Common Ground UART data output LED Driver
+44(0) 207 428 2647 | sales@lm-technologies.com LM746 Bluetooth Dual Mode Audio Module Standalone (With Embedded Bluetooth 5 Compliant Stack) Product Part No LM746 See Last Page Pin Assignments Continued Pin Name Type Open drain output Open drain output Supply Domain PIO_POWER PIO_POWER Description LED Driver LED Driver LED1 LED2 PIO0 PIO1 PIO2 PIO3 PIO4 PIO5 PIO6 PIO7 Bi-directional with weak pull-down PIO_POWER Bi-directional with weak pull-down PIO_POWER Bi-directional with weak pull-down PIO_POWER Bi-directional with weak pull-down PIO_POWER Bi-directional with weak pull-down PIO_POWER Bi-directional with weak pull-down PIO_POWER Bi-directional with weak pull-down PIO_POWER Bi-directional with weak pull-down PIO_POWER 3V3_USB 3V3_USB 0V USB_DP USB_DN Bi-directional Bi-directional PIO_POWER VDD GND 1V8_SMPS VBAT Ground VDD Battery terminal +ve VBAT_SENSE VCHG CHG_EXT Charger input VREG_ENABLE Analogue Bi-directional weak pull-down Bi-directional weak pull-up PIO_POWER PIO_POWER Programmable input / output line Programmable input / output line Programmable input / output line Programmable input / output line Programmable input / output line Programmable input / output line Programmable input / output line Programmable input / output line USB data +
USB data -
Positive supply for PIO Common Ground 1V8 Output Lithium ion/polymer battery positive terminal. Battery charger output and input to switch mode regulator. Battery charger sense input Lithium ion/polymer battery charger input External charger control Otherwise leave unconnected Regulator enable input UART clear to send, active low. UART request to send, active low. Alt PIO16. UART_CTS UART_RTS MIC_LN 46 MIC_LP 46 MIC_LP 48 MIC_RN 48 MIC_RN MIC_RP Analogue Analogue Analogue Analogue Analogue Analogue 47 MIC_BIAS_A Analogue MIC_BIAS_B Analogue SPKR_RN SPKR_RP SPKR_LN SPKR_LP GND Analogue Analogue Analogue Analogue Ground VDD_AUDIO (1.35V) VDD_AUDIO (1.35V) VDD_AUDIO (1.35V) VBAT/3V3_USB VDD_AUDIO (1.35V) VDD_AUDIO (1.35V) VDD_AUDIO (1.35V) VBAT/3V3_USB Microphone input negative, left. Microphone input positive, left. Microphone input positive, left. Microphone bias A Microphone input negative, right Microphone input negative, right Microphone input positive, right Microphone bias B VDD_AUDIO_DRV (1V8_SMPS) Speaker output negative, right VDD_AUDIO_DRV (1V8_SMPS) Speaker output positive, right VDD_AUDIO_DRV (1V8_SMPS) Speaker output negative, left VDD_AUDIO_DRV (1V8_SMPS) Speaker output positive, left 0V Common Ground 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 49 50 51 52 53 54 55 LM746 Page 4 of 21
+44(0) 207 428 2647 | sales@lm-technologies.com LM746 Bluetooth Dual Mode Audio Module Standalone (With Embedded Bluetooth 5 Compliant Stack) Product Part No LM746 See Last Page General Electrical Specication Absolute Maximum Ratings Min Max Recommended Operating Condition Min
-40 C
+85 C Operating Temperature Range
-20 C
-0.4V
-0.4V
-0.4V
-0.4V
-0.4V
-0.4V 5.75V 4.4V 5.75V 4.4V 4.4V 3.6V Supply Voltage (VCHG) Supply Voltage (VBAT) Supply Voltage (VBAT_SENSE) Supply Voltage (VREG_ENABLE) Supply Voltage (LED [2:0] ) Supply Voltage (PIO_POWER) Storage Temperature Supply Voltage (VCHG) Supply Voltage (VBAT) Supply Voltage (VBAT_SENSE) Supply Voltage (VREG_ENABLE) Supply Voltage (LED [2:0] ) Supply Voltage (PIO_POWER) 1.8V Switch-mode Regulator 1.8V Switch-mode Regulator Input Voltage (VBAT) Output Voltage (1V8_SMPS) Normal Operation Transient setting time Load current Max
+75 C 5.75V 4.25V 4.25V 4.25V 4.25V 3.6V Unit V V s mA mA
%
MHz s mA mA
%
kHz 4.75V / 3.10V 2.5V 0V 0V 1.10V 1.7V Max 4.25 1.90
-
185 25
-
4.00
-
5 5
-
200 Min 2.80 1.70
-
-
-
-
3.63
-
0.005
-
-
100 Typ 3.70 1.80 30
-
-
90 4.00 200
-
-
85
-
Current available for external use, stereo audio with 16 load (a) Peak conversion efficiency Switching frequency Low Power Mode, automatically entered in Deep Sleep Transient setting time Load current Current available for external use Peak conversion efficiency Switching frequency Regulator Enable VREG_ENABLE, Switching Threshhold Rising Threshold
(a) = More current available for audio loads above 16 Min 1.0 Typ
-
Max
-
Unit V LM746 Page 5 of 21
+44(0) 207 428 2647 | sales@lm-technologies.com LM746 Bluetooth Dual Mode Audio Module Standalone (With Embedded Bluetooth 5 Compliant Stack) Product Part No LM746 See Last Page Battery Charger Battery Charger Input Voltage, VCHG (a)
(a) = Reduced specication from 3.1 to 4.75. Full specication > 4.75V Trickle Charge Mode Charge current Itrickle as percentage of fast charge current Vfast rising threshold Vfast rising threshold trim step size Vfast falling threshold Fast Charge Mode Charge current during constant Max headroom > 0.55V Current mode, Ifast Min headroom > 0.55V Reduced headroom charge current, as a percentage of Ifast Mid headroom = 0.15V I-CTRL charge current step size Voat threshold, calibrated Standby Mode Voltage hysteresis on VBAT, Vhyst Error Charge Mode Headroom (a) error rising threshold Headroom (a) error threshold hysteresis
(a) = Headroom = VCHG-VBAT External Charge Mode Fast charge current Ifast Control current into CHG_EXT Voltage on CHG_EXT External pass device hfe Min 4.75 / 3.10 Min 8
-
-
-
Min 194 50
-
4.16 Min 100 Min 30 20 Min 200 0 0
-
Typ 5.00 Typ 10 2.9 0.1 2.8 Typ 200 10
-
10 4.20 Typ
-
Typ
-
-
Typ
-
-
50 Max 5.75 Max 12
-
-
-
Max 206 100
-
4.24 Max 150 Max 50 30 Max 500 20 5.75
-
Unit V Unit
%
V V V Unit mA mA
%
mA V Unit mV Unit mV mV Unit mA mA V
-
Sense voltage, between VBAT_SENSE and VBAT at max current
(a) = In the external mode, the battery charger meets all the previous charger electrical characteristics and the additional or superceeded elecectrical characteristics are listed in this table 200 205 195 mV Stereo Codec: Analogue to Digital Converter Parameter Resolution Input Sample Rate Fsample SNR Conditions
-
-
n = 1kHz Fsample B/W = 20Hz--Fsample/2 8kHz
(20kHz max) A-Weighted THD+N < 1%
1.6Vpk-pk input 16kHz 32kHz 44.1kHz 48kHz Min Typ
-
8
-
-
-
-
-
-
-
93 92 92 92 92 Max 16 48
-
-
-
-
-
Unit Bits kHz dB dB dB dB dB LM746 Page 6 of 21
+44(0) 207 428 2647 | sales@lm-technologies.com LM746 Bluetooth Dual Mode Audio Module Standalone (With Embedded Bluetooth 5 Compliant Stack) Product Part No LM746 See Last Page Stereo Codec: Analogue to Digital Converter Continued... Parameter THD+N Digital gain Analogue gain Conditions n = 1kHz B/W = 20Hz--Fsample/2
(20kHz max) 1.6Vpk-pk input Digital gain resolution = 1 / 32 Pre-amplier setting
= 0dB, 9dB, 21dB or 30dB Analogue setting
= -3dB to 12dB in 3dB steps Fsample 8kHz 48kHz Min Typ Max Unit
-
-
-24
-3 0.004 0.008
-
-
-
-
21.5 42
%
%
dB dB Stereo seperation (crosstalk)
-
-89
-
dB Stereo Codec: Digital to Analogue Converter Parameter Resolution Output Sample Rate Fsample Conditions
-
-
SNR n = 1kHz Fsample Load B/W = 20Hz--20kHz A-Weighted THD+N < 0.1%
0dBFS input Parameter THD+N Conditions n = 1kHz B/W = 20Hz--20kHz 0dBFS input 48kHz 48kHz 48kHz 100 32 16 Fsample Load 8kHz 8kHz 8kHz 48kHz 48kHz 48kHz 100k 32 16 100k 32 16 Digital Gain Analogue Gain Digital Gain Resolution = 1 /32 Analogue Gain Resolution = 3dB Stereo seperation (crosstalk) Min Typ
-
8
-
-
-
-
-
96 96 96 Max 16 96
-
-
-
Unit Bits kHz dB dB dB Min Typ Max Unit
-
-
-
-
-
-
-24
-21
-
0.002 0.002 0.003 0.003 0.003 0.004
-
-
-88
-
-
-
-
-
-
21.5 0
-
%
%
%
%
%
%
dB dB dB LM746 Page 7 of 21
+44(0) 207 428 2647 | sales@lm-technologies.com LM746 Bluetooth Dual Mode Audio Module Standalone (With Embedded Bluetooth 5 Compliant Stack) Product Part No LM746 See Last Page Digital Digital Terminals Input Voltage VIL input logic level low VIH input logic level high Tr/Tf Output Voltage VOL output logic level low, IOL = 4.0mA Min
-0.4 0.7xPIO_POWER
-
-
VIH output logic level high, IOH = -0.4mA
.75xPIO_POWER Tr/Tf Input and Tristate Currents Strong pull-up Strong pull-down Weak pull-up Weak pull-down CI input Capacitance LED Driver Pads LED Driver Pads Current, IPAD
-
-150 10
-5 0.33 1.0 High impedance state Current sink state LED pad voltage, VPAD LED pad resistance IPAD = 10mA VPAD < 0.5V VOL output logic level low(a) VOH output logic level high(a) VIL input logic level low VIH input logic level high
(a) LED output port is open-drain and requires a pull-up Auxiliary ADC Auxiliary ADC Resolution Input voltage range(a) Accuracy
(Guaranteed monotonic) Offset Gain error Input bandwidth Conversion time Sample rate(b)
(a) LSB size = VDD_AUX/1023 INL DNL Typ
-
-
-
-
-
-
-40 40
-1.0 1.0 Min Typ
-
-
-
-
-
-
-
-
-
-
-
-
0 0.8 0 0.8 Min Typ
-
0
-1 0
-1
-0.8
-
1.38
-
-
-
-
-
-
-
100 1.69
-
Max 0.4 PIO_POWER+0.4 25 0.4
-
5
-10 150
-0.33 5.0 5.0 Max 5 10 0.55 40
-
-
-
-
Max 10 1.35 1 1 1 0.8
-
2.75 700 Unit V V ns V V ns uA uA uA uA pF Unit A mA V V V V V Unit Bits V LSB LSB LSB
%
kHz s Samples/s
(b) The auxiliary ADC is accessed through a VM function. The sample rate given is achieved as part of this function. LM746 Page 8 of 21
+44(0) 207 428 2647 | sales@lm-technologies.com LM746 Bluetooth Dual Mode Audio Module Standalone (With Embedded Bluetooth 5 Compliant Stack) Product Part No LM746 See Last Page Auxiliary DAC Auxiliary DAC Resolution Supply voltage, VDD_DAC Output voltage range Full-scale output voltage LSB size Offset Integral non-linearity Settling time(a) Min
-
1.30 0 1.30 0
-1.32
-1
-
Typ
-
1.35
-
1.35 1.32 0 0
-
Max 10 1.40 1.35 1.40 2.64 1.32 1 250 Unit Bits V V V mV mV LSB ns
(a) The settling time does not include any capacitive load RF Specication: Temperature = +20 C Transmitter Maximum RF transmit power RF power variation over temperature range with compensation enabled RF power variation over temperature range with compensation disabled 20dB bandwidth for modulated carrier Adjacent channel transmit power F = F0 2MHz Adjacent channel transmit power F = F0 3MHz Adjacent channel transmit power F = F0 > 3MHz f1avg Maximum Modulation f2max Minimum Modulation f2avg/f1avg Initial carrier frequency tolerance Drift Rate Drift (single slot packet) Drift (ve slot packet) 2nd Harmonic Content 3rd Harmonic Content RF Specication: Temperature = +20 C Receiver Sensitivity at 0.1% BER for all packet types 2.402 2.441 2.480 Maximum received signal at 0.1% BER C/I co-channel Adjacent channel selectivity C/I F = F0 + 1MHz Adjacent channel selectivity C/I F = F0 - 1MHz Adjacent channel selectivity C/I Min
-6
-
-
-
-
-
-
140 115 0.8
-75
-
-
-
-
-
Min
-
-
-
-20
-
-
-
-
Typ 2 0.5 1.5 925
-23
-32
-65 165 137 0.9 15 5 15 15
-40
-55 Typ
-87
-90
-90
>-10 5
-5
-3
-35 Max Bluetooth Specication Unit
-
-
-
-6 to +4
-
-
1000 1000
-20
-40
-40 140<f1avg<175 115 0.80 75 20 25 40
-30
-30
-20
-28
-40 175
-
-
75 20 25 40
-
-
Max
-83
-86
-86
-
11 0 0
-70
-20 11 0 0
-30
-30 Bluetooth Specication Unit dBm dB dB kHz dBm dBm dBm kHz kHz
-
kHz kHz/50 kHz kHz dBm dBm dBm dBm dB dB dB dB LM746 Page 9 of 21
+44(0) 207 428 2647 | sales@lm-technologies.com LM746 Bluetooth Dual Mode Audio Module Standalone (With Embedded Bluetooth 5 Compliant Stack) Product Part No LM746 See Last Page RF Specication: Temperature = +20 C Continued... Receiver F = F0 + 2MHz Adjacent channel selectivity C/I F = F0 - 2MHz Adjacent channel selectivity C/I F = F0 + 3MHz Adjacent channel selectivity C/I F = F0 - 5MHz Adjacent channel selectivity C/I F = FImage Maximum level of intermodulation interferers Spurious output level 1. Serial Interface 1.1 USB Interface Min Typ Max Bluetooth Specication Unit
-
-
--
-
-39
-
-25
-45
-45
-20
-23
-155
-20
-40
-40
-9
-
-
-20
-40
-40
-9
-39 dB dB dB dB dBm dBm/Hz LM746 has a full-speed (12Mbps) USB interface for communicating with other compatible digital devices. The USB interface on LM746 acts as a USB peripheral, responding to requests from a master host controller. LM746 contains internal USB termination resistors and requires no external resistor matching. LM746 supports the Universal Serial Bus Specication, Revision v2.0 (USB v2.0 Specication), supports USB standard charger detection and fully supports the USB Battery Charging Specication, available from http://www.usb.org. For more information on how to integrate the USB interface on LM746 see the Bluetooth and USB Design Considerations Application Note. As well as describing USB basics and architecture, the application note describes:
Power distribution for high and low bus-powered congurations Power distribution for self-powered conguration, which includes USB VBUS monitoring USB enumeration Electrical design guidelines for the power supply and data lines, as well as PCB tracks and the effects of ferrite beads USB suspend modes and Bluetooth low-power modes:
- Global suspend
- Selective suspend, includes remote wake
- Wake on Bluetooth, includes permitted devices and set-up prior to selective suspend - Suspend mode current draw
- PIO status in suspend mode
- Resume, detach and wake PIOs Battery charging from USB, which describes dead battery provision, charge currents, charging in suspend modes and USB VBUS voltage considera-
tion USB termination when interface is not in use Internal modules, certication and non-specication compliant operation LM746 Page 10 of 21
+44(0) 207 428 2647 | sales@lm-technologies.com LM746 Bluetooth Dual Mode Audio Module Standalone (With Embedded Bluetooth 5 Compliant Stack) Product Part No LM746 See Last Page 1. Serial Interface 1.2 Programming and Debug Interface LM746 provides a debug SPI interface for programming, conguring (PS Keys) and debugging the LM746. Access to this interface is required in production. Ensure the 4 SPI signals and the SPI line are brought out to either test points or a header. To use the SPI interface, the SPI line requires the option of being pulled high externally. 2. Interfaces 2.1 Analogue I/O Ports, AIO LM746 has 2 general-purpose analogue interface pin, AIO[0] & AIO[1]. Typically, this connects to a thermistor for battery pack temperature measure-
ments during charge control. 2.2 LED Drivers LM746 includes a 3-pad synchronised PWM LED driver for driving RGB LEDs for producing a wide range of colours. All LEDs are controlled by rmware. The terminals are open-drain outputs, so the LED must be connected from a positive supply rail to the pad in series with a current-limiting resistor. LED Forward Voltage, VF D E L I RLED Resistor Voltage Drop, V R LED[2, 1 or 0]
Pad Voltage VPAD R =20 ON From Figure 2.1 it is possible to derive Equation 2.1 to calculate ILED. If a known value of current is required through the LED to give a specic luminous intensity, then the value of RLED is calculated. Figure 2.1: LED Equivalent Circuit VDD - VF I LED
=
+
RLED RON Equation 2.1: LED Current For the LED pads to act as resistance, the external series resistor, RLED, needs to be such that the voltage drop across it, VR, keeps VPAD below 0.5V. Equation 2.2 also applies. VDD = VF + VR + VPAD Equation 2.2: LED PAD Voltage Note: The LED current adds to the overall current. Conservative LED selection extends battery life. LM746 Page 11 of 21
+44(0) 207 428 2647 | sales@lm-technologies.com LM746 Bluetooth Dual Mode Audio Module Standalone (With Embedded Bluetooth 5 Compliant Stack) Product Part No LM746 See Last Page 3. Power Control and Regulation 3.1 Voltage Regulator Enable When using the integrated regulators the voltage regulator enable pin, VREG_ENABLE, enables the LM746 and the following regulators:
-1.8V switch-mode regulator
-1.35V switch-mode regulator
-Low-voltage VDD_DIG linear regulator
-Low-voltage VDD_AUX linear regulator The VREG_ENABLE pin is active high. LM746 boots-up when the voltage regulator enable pin is pulled high, enabling the regulators. The rmware then latches the regulators on, it is then permitted to release the voltage regulator enable pin. The status of the VREGENABLE pin is available to rmware through an internal connection. VREGENABLE also works as an input line. 3.2 Reset, RST#
LM746 is reset from several sources:
-RST# pin
-Power-on reset
-USB charger attach reset
-Software congured watchdog timer The RST# pin is an active low reset and is internally ltered using the internal low frequency clock oscillator. LM Developes recommends applying RST#
for a period >5ms. At reset the digital I/O pins are set to inputs for bidirectional pins and outputs are set to tristate. 4. Battery Charger 4.1 Battery Charger hardware Operating Modes The battery charger hardware is controlled by the VM. The battery charger has 5 modes:
-Disabled
-Trickle charge
-Fast charge
-Standby: fully charged or oat charge
-Error: charging input voltage, VCHG, is too low The battery charger operating mode is determined by the battery voltage and current. The internal charger circuit can provide up to 200mA of charge current, for currents higher than this the LM746 can control an external pass transistor 4.2 External Mode The external mode is for charging higher capacity batteries using an external pass device. The current is controlled by sinking a varying current into the CHG_EXT pin, and the current is determined by measuring the voltage drop across a resistor, Rsense, connected in series with the external pass device, see Figure 4.2.1. The voltage drop is determined by looking at the difference between the VBAT_SENSE and VBAT pins. The voltage drop across Rsense is typically 200mV. The value of the external series resistor determines the charger current. This current can be trimmed with a PS Key. In Figure 4.2.1, R1 (220m) and C1 (4.7F) form a RC snubber that is required to maintain stability across all battery ESRs. The battery ESR must be <1.0 LM746 Page 12 of 21
+44(0) 207 428 2647 | sales@lm-technologies.com LM746 Bluetooth Dual Mode Audio Module Standalone (With Embedded Bluetooth 5 Compliant Stack) Product Part No LM746 See Last Page 4. Battery Charger Continued... Figure 4.2.1: Battery Charger External Mode Typical Conguration TR 1 External Pass Device Rsense
+
-
BAT 1 Li+ Cell VCHG CHG_EXT VBAT_SENSE VBAT R1 220m C1 4.7uF 5. Flash Memory 5.1 eFlash Memory Figure 4.2.2: Optional Ancilliary Circuits In Figure 4.2.2, Optional fast charge,400m = 500m. Connect VBAT_SENSE to VBAT if not using this circuit. VBUS CHG_EXT 1 3 Q100 BCX51 VBAT_SENSE 2 R104 1%
400mR VBAT C105 4u7 R108 220mR The internal ash memory provides 16Mb of internal code and data storage. For improved performance, the internal ash memory has 45ns access time and is organised as 64-bit wide. 5.2 Serial Quad I/O Flash (Optional) LM746 supports serial ash. This enables additional data storage areas for device specic data. LM746 use the Serial Quad I/O Flash 4Mb Flash. 6. Capacitive Touch Sensor LM746 capacitive touch sensor interface features:
-Support for up to 6 capacitive touch sensing electrodes
-Printed on the PCB
-Made from ex PCB
-Conguration for individual buttons
-Conguration for a wipe-type arrangement where 2 or more pads sense taps at each end or a wipe from one side to the other
-Operates in deep sleep and is a programmable source for wake-up LM746 Page 13 of 21
+44(0) 207 428 2647 | sales@lm-technologies.com LM746 Bluetooth Dual Mode Audio Module Standalone (With Embedded Bluetooth 5 Compliant Stack) Product Part No LM746 See Last Page Figure 6.1 shows the system block diagram for the capacitive touch sensor interface. The interface depends on the capacitive touch sensor type. Therefore the overall control of the capacitive touch sensor interface resides in the VM, so it is easily modied in each end-user application. CAP_SENSE[0]
CAP_SENSE[1]
CAP_SENSE[2]
CAP_SENSE[3]
CAP_SENSE[4]
CAP_SENSE[5]
Capacitive Range Control Sampling Font-end ADC Figure 6.1: Capacitive Touch Sensor Block Diagram Digital Processing Firmware VM The overall system-level specication for the capacitive touch sensor interface on the LM746 Module is:
6 inputs multiplexed in to 1 touch sensor on the front-end Capacitances of 0pF to 50pF measured with a resolution of 4fF, where a touch is assumed to be between 50fF and 1pF Each reading takes 172s 6 pads read every 1.03ms System auto-calibrates to remove parasitic and environmental effects including PCB construction Temperature Humidity Works in normal and deep sleep modes System current is approximately 50A from the battery The touch sensor also functions like a PIO The system block diagram in Figure 6.1 highlights the top-level architecture for the capacitive touch sensor interface, it consists of:
Capacitive range control Sets the rough capacitance of the touch sensor pad, which is product dependent Splits into 4 integrated capacitors The VM selects which capacitors are enabled, i.e. the range capacitance Sampling front end An internal capacitance is trimmed by the digital state machine ensuring Touch Capacitance = Range Capacitance + Internal Capacitance When the internal capacitance is correctly trimmed: The sense voltage is 0V A touch changes the touch capacitance, which then changes the sense voltage ADC: Uses a successive approximation, charge redistribution ADC Clocked at 64kHz 9-bit resolution, where LSB is 2fF and full range is 1pF The internal capacitance is a 7-bit variable capacitor with 114fF steps and 14.5pF range LM746 Page 14 of 21
+44(0) 207 428 2647 | sales@lm-technologies.com LM746 Bluetooth Dual Mode Audio Module Standalone (With Embedded Bluetooth 5 Compliant Stack) Product Part No LM746 See Last Page The internal capacitance is trimmed, putting it in the mid range of the ADC. This enables measurements from 0pF to 50pF, where a capacitive touch is between 50fF and 1pF. Digital signal conditioning:
Only the enabled inputs are scanned Enabling fewer inputs increases readings per second Averaging of ADC readings reduces noise, this is software programmable from 1 to 64 readings in intervals to the power of 2 The internal capacitance updates using a rolling average of the ADC readings, software programmable from 1 to 215 readings in intervals to the power of 2. For example, 32768 readings take approximately:
5.6s if polling one pad (no averaging) 33.8s if polling 6 pads (no averaging) Pulse skipping mode is possible, reducing the current consumption. Here the system waits a programmable number of 64kHz clock cycles (maximum 29) before the next read, i.e. an 8ms maximum pause. ADC trigger level is software programmable. If the threshold is crossed the rmware gets an interrupt. 6 hardware event registers store the pad number and trigger time, which enables the system to sense swipes. Programmable hysteresis, with one value for all pads Software signal conditioning (rmware):
The rmware reads ADC and Cint values after an interrupt as the hardware only stores the pad number and trigger time Digital state machine scans pads and calibrates the internal capacitance If a swipe happens in deep sleep the rmware reads the trigger order and event time when it wakes up. It then reads the last ADC reading for each input, not the reading that triggered the interrupt. VM:
Congures the hardware and gets an interrupt when a programmable threshold is crossed Selects the range capacitance Decides whether an event is a valid touch LM746 Page 15 of 21
+44(0) 207 428 2647 | sales@lm-technologies.com LM746 Bluetooth Dual Mode Audio Module Standalone (With Embedded Bluetooth 5 Compliant Stack) Product Part No LM746 See Last Page LM746 Page 16 of 21
+44(0) 207 428 2647 | sales@lm-technologies.com LM746 Bluetooth Dual Mode Audio Module Standalone (With Embedded Bluetooth 5 Compliant Stack) Product Part No LM746 See Last Page Physical Dimensions Top View 55 Pin 1 5.6mm m m 6 1 Front View Side View 36 35 0.9 0.6 0.9mm 0.9mm Pin Spacing 1.70 20 0 2
. 1 2.3mm 2.3mm 22.7mm 23.9mm 23.9mm 16mm LM746 Page 17 of 21
+44(0) 207 428 2647 | sales@lm-technologies.com LM746 Bluetooth Dual Mode Audio Module Standalone (With Embedded Bluetooth 5 Compliant Stack) Product Part No LM746 See Last Page PCB Footprint Optimal Placement Position EDGE OF HOST PCB
( Optimal ) Pin 1 Placement Note If the optimal placement position cannot be achieved, ensure there is no metal beneath the highlighted part of module. highlighted NB Aim to place the module away from interference.
(i.e: place the module at the edge of the board.) m m 6 1 LM746 Page 18 of 21 NO METAL BENEATH THIS AREA Pin 1 55 Pin 1 5.6mm 23.9mm 36 35 1.70 20 0.9 0.9 Pin Spacing
+44(0) 207 428 2647 | sales@lm-technologies.com LM746 Bluetooth Dual Mode Audio Module Standalone (With Embedded Bluetooth 5 Compliant Stack) Product Part No LM746 See Last Page Tray Dimensions 314mm m m 0 4 1 Quantitites 1 Tray = 30 modules 10 Trays = 300 modules 20 Trays = 600 modules The trays are stacked and inserted into an anti-static vacuum bag and the Anti-Static Label, Model Name Label and Moisture Sensitive Labels stuck on. drying agent Humidity Indicator Card Anti-static aluminium vacuum bag. The vacuum bag is placed inside the box and a Model Name Label stuck on the front-side of each box. Anti-static aluminium vacuum bag. box LM746 Page 19 of 21 Model name label box
) carton carton label Each carton contains 4 boxes.
+44(0) 207 428 2647 | sales@lm-technologies.com LM746 Bluetooth Dual Mode Audio Module Standalone (With Embedded Bluetooth 5 Compliant Stack) Product Part No LM746 See Below Datasheet Version Notes v1.0 18 APR 2018 Added version notes to datasheet. Added Bluetooth 5 Complaint. LM746 Page 20 of 21
+44(0) 207 428 2647 | sales@lm-technologies.com LM746 Bluetooth Dual Mode Audio Module Standalone (With Embedded Bluetooth 5 Compliant Stack) Product Part No LM746 See Below LM746 Packaging Options 746-0420 LM746 Module MOD SMT PROG BT4.1 D/Mode FwA20Rx IC ANT TRAY 746-0421 LM746 Module MOD SMT PROG BT4.1 D/Mode FwA20HIC IC ANT TRAY LM746 Page 21 of 21
+44(0) 207 428 2647 | sales@lm-technologies.com