SARA-G3 and SARA-U2 series - System Integration Manual 
UBX-13000995 - R26    Contents 
    Page 5 of 217 
Contents 
Preface ................................................................................................................................ 4 
Contents .............................................................................................................................. 5 
1  System description ..................................................................................................... 10 
1.1  Overview ............................................................................................................................................ 10 
1.2  Architecture ........................................................................................................................................ 13 
1.2.1  Internal blocks ............................................................................................................................. 15 
1.3  Pin-out ............................................................................................................................................... 17 
1.4  Operating modes ................................................................................................................................ 22 
1.5  Supply interfaces ................................................................................................................................ 24 
1.5.1  Module supply input (VCC) ......................................................................................................... 24 
1.5.2  RTC supply input/output (V_BCKP) .............................................................................................. 33 
1.5.3  Generic digital interfaces supply output (V_INT) ........................................................................... 34 
1.6  System function interfaces .................................................................................................................. 35 
1.6.1  Module power-on ....................................................................................................................... 35 
1.6.2  Module power-off ....................................................................................................................... 39 
1.6.3  Module reset ............................................................................................................................... 41 
1.6.4  External 32 kHz signal input (EXT32K) ......................................................................................... 42 
1.6.5  Internal 32 kHz signal output (32K_OUT) .................................................................................... 42 
1.7  Antenna interface ............................................................................................................................... 43 
1.7.1  Antenna RF interface (ANT) ......................................................................................................... 43 
1.7.2  Antenna detection interface (ANT_DET) ...................................................................................... 44 
1.8  SIM interface ...................................................................................................................................... 44 
1.8.1  (U)SIM card interface ................................................................................................................... 44 
1.8.2  SIM card detection interface (SIM_DET) ....................................................................................... 44 
1.9  Serial interfaces .................................................................................................................................. 45 
1.9.1  Asynchronous serial interface (UART) .......................................................................................... 46 
1.9.2  Auxiliary asynchronous serial interface (AUX UART) ..................................................................... 59 
1.9.3  USB interface .............................................................................................................................. 63 
1.9.4  DDC (I
2
C) interface ...................................................................................................................... 66 
1.10  Audio interface ............................................................................................................................... 68 
1.10.1  Analog audio interface ................................................................................................................ 68 
1.10.2  Digital audio interface ................................................................................................................. 70 
1.10.3  Voice-band processing system ..................................................................................................... 72 
1.11  General Purpose Input/Output (GPIO) ............................................................................................. 76 
1.12  Reserved pins (RSVD) ...................................................................................................................... 80 
1.13  System features............................................................................................................................... 81 
1.13.1  Network indication ...................................................................................................................... 81 
1.13.2  Antenna detection ...................................................................................................................... 81 
1.13.3  Jamming detection ...................................................................................................................... 81