CLM920 TD3 LTE Module Hardware Usage Guide
Shanghai Yuge Information Technology co., LTD
- 57 -
Pin
Signal
name
Description
para
meter
Level value (V)
Remarks
Min Typical Max
44
ADC1
Analog to digital
converter interface 0
VIN
0.3
VBAT
ADC resolution
15Bits
45
ADCO
Analog to digital
converter interface 0
VIN
0.3
VBAT
ADC resolution
15Bits
3.19 RF interface
CLM920 TD3 module provides three-way antenna interface, one main set antenna
interface, responsible for 4G, 3G, 2G signals of transceiver module, one-way diversity
antenna interface, responsible for receiving 4G, 3G signals, and signal degradation caused by
multi-path under high-speed movement The signal can be enhanced by adding a diversity
antenna, and a GNSS antenna interface is used for GPS, Beidou, GLONASS, and GALILEO
signal reception, and can provide a positioning solution for the user. Three-way antenna
interface impedance is 50 ohms.
Table 3-28 Antenna interface pin definition
Pin Signal name
I/O Description
Remarks
49
ANT_MAIN
IO Main antenna interface
50
Ω
characteristic impedance
35
ANT_DIV
AI Diversity antenna interface 50
Ω
characteristic impedance
47
ANT_GNSS
AI GNSS antenna interface
50
Ω
characteristic impedance
3.19.1 Main antenna interface
The 49-pin of the CLM920 TD3 is the main set antenna interface. To facilitate the
debugging of the antenna, it is necessary to add a
π
-type matching circuit to the
motherboard, and take the 50-ohm impedance line. The recommended circuit is as follows
：
Figure 3-28 Main antenna matching circuit
