User's Manual

L
LE920 Hardware User Guide
1vv0301026 Rev.0 - draft4 – 2013-05-
Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved. Page 6 of 76
4.3.2. Hardware Shutdown ...................................................................................................... 29
4.3.3. Hardware Unconditional Restart ................................................................................... 30
4.3.4. Hardware Unconditional Shutdown ............................................................................... 31
4.4. Summary of Turning ON and OFF the module .......................................................... 32
5.
Power Supply ....................................................................................................... 33
5.1. Power Supply Requirements ..................................................................................... 33
5.2. General Design Rules ................................................................................................ 35
5.2.1. Electrical Design Guidelines .......................................................................................... 35
5.2.1.1. + 5V Input Source Power Supply Design Guidelines .............................................. 35
5.2.1.2. + 12V Input Source Power Supply Design Guidelines............................................. 36
5.2.1.3. Battery Source Power Supply Design Guidelines ................................................... 38
5.2.2. Thermal Design Guidelines............................................................................................ 39
5.2.3. Power Supply PCB Layout Guidelines ........................................................................... 40
6.
Antenna(s) ........................................................................................................... 42
6.1. GSM/WCDMA/LTE Antenna Requirements ............................................................... 42
6.2. GSM/WCDMA/LTE Antenna – PCB line Guidelines ................................................... 43
6.3. GSM/WCDMA/LTE Antenna – Installation Guidelines ............................................... 44
6.4. Antenna Diversity Requirements............................................................................... 44
6.5. GPS/GNSS Antenna Requirements ........................................................................... 45
6.5.1. Combined GPS/GNSS Antenna ...................................................................................... 45
6.5.2. Linear and Patch GPS/GNSS Antenna ........................................................................... 46
6.5.3. Front End Design Considerations .................................................................................. 46
6.5.4. GPS/GNSS Antenna - PCB Line Guidelines ................................................................... 46
6.5.5. GPS/GNSS Antenna – Installation Guidelines ............................................................... 47
7.
Logic Level Specifications .................................................................................... 48
8.
USB Port .............................................................................................................. 49
9.
Serial Ports .......................................................................................................... 50
9.1. Modem Serial Port 1 .................................................................................................. 51
9.2. Modem Serial Port 2 .................................................................................................. 52
9.3. RS232 Level Translation ............................................................................................ 52
10.
Audio Section Overview ..................................................................................... 54