Table 3: Pin description
Pin name I/O Description Comment
Power Supply
VBAT_RF/VBAT_BB Power supply voltage
VRTC I/O Power supply for RTC
If it is unused, keep open.
VREG_AUX O LDO power output
GND Ground
Power on/off
POWER_ON I
POWER_ON should be pulled low at
least 64ms to power on or 500ms to
power off the module.
Audio interface
MIC1P
I Differential audio input
If it is unused, connect to
ground through a 100N
capacitor.
MIC1N
EAR1P
O
Differential audio output
If these pins are unused,
keep open.
EAR1N
SPK_P
O
SPK_N
USIM interface
V_USIM O
Voltage Supply for SIM card
Support 1.8V or 3V SIM card
All signals of SIM
interface should be
protected against
ESD/EMC.
SPI interface
SPI_CLK O SPI clock
If it is unused, keep open.
SPI_CS_N O SPI chip-select