User's Manual
LE940B6 Hardware User Guide
1VV0301331 Rev. 1.8 - 2017-03-15
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4.2.
Recommended Operating Conditions ............................................................. 39
4.3.
Logic Level Specifications ................................................................................. 40
4.3.1.
1.8V Standard GPIOs ............................................................................ 40
4.3.2.
1.8V I2C Pads ........................................................................................ 41
4.3.3.
1.2V EMIC Pads ..................................................................................... 41
4.3.4.
1.8V/2.9V SIM Pads .............................................................................. 42
4.3.5.
USB........................................................................................................ 42
4.3.6.
2.5V/3.3V EMAC Interface for RMII and RGMII ................................... 43
5.
Hardware Commands ....................................................................................... 44
5.1.
Turning on the LE940B6 Module ..................................................................... 44
5.2.
Initialization and Activation State .................................................................... 44
5.3.
Turning off the LE940B6 Module ..................................................................... 48
5.3.1.
Shutdown by Software Command ....................................................... 48
5.3.2.
Hardware Shutdown ............................................................................. 50
5.3.3.
Unconditional Hardware Reset (RESET_N)........................................... 51
5.3.4.
Unconditional Hardware Shutdown ..................................................... 52
6.
Power Supply ................................................................................................... 54
6.1.
Power Supply Requirements............................................................................ 54
6.2.
General Design Rules ....................................................................................... 57
6.2.1.
Electrical Design Guidelines .................................................................. 57
6.2.1.1.
+ 5V Input Source Power Supply – Design Guidelines ......... 57
6.2.1.2.
+ 12V Input Source Power Supply – Design Guidelines ....... 58
6.2.1.3.
Battery Source Power Supply – Design Guidelines .............. 60
6.2.2.
Thermal Design Guidelines ................................................................... 61
6.2.3.
Power Supply PCB Layout Guidelines ................................................... 61
7.
Antenna(s) ....................................................................................................... 63
7.1.
GSM/WCDMA/TD-SCDMA/LTE Antenna Requirements ................................. 63
7.2.
GSM/WCDMA/TD-SCDMA/LTE Antenna – PCB Line Guidelines ..................... 63
7.3.
GSM/WCDMA/TD-SCDMA/LTE Antenna – Installation Guidelines ................. 65
7.4.
Secondary Antenna Requirements .................................................................. 65