Product Manual

MeiGProductManualofSLM750Module
SLM750ModuleHardwareDesign Page 59, total 84 pages
4.3 Layout Guideline
You need to follow the layout guidelines in the below when designing:
 Maximize the distance between the GNSS antenna, the main antenna and the diversity
antenna.
 Noisy digital circuits such as the USIM card, USB interface, Camera module, Display
connector and SD card should be kept away from the antenna.
 Use ground vias around the GNSS trace and sensitive analog signal traces to provide
isolation and protection.
 Keep 50ohm characteristics impedance of the ANT_GNSS trace.
See Chapter 5 for GNSS reference design and antenna consideration.
5 Antenna Interface
Table 24: RF antenna pin definition
Pin name Pin no. Description I/O Note
ANT_MAIN
49
Main antenna
IO
50Ω impedance
ANT_DIV
35
Diversity antenna
AI
50Ω impedance
ANT_GNSS
47
GNSS antenna AI 50Ω impedance
5.1 Antenna Interface
SLM750 provides 3 antenna pins: ANT_MAIN, ANT_DIV, ANT_GNSS. Select connection
(open) Altitude <4m (50%); <8m (90%)
Speed accuracy Speed <0.2m/s
First positioning time
TTFF
Cold start 32s
Warm start 29s
Hot start 2s
Sensitivity Capturing -154dBm
Tracking -156dBm
Serial output baud rate 300bit/s~230400bit/s
GPS receiving 12 channel,GPS L1(1575.42MHz),C/A code
Data update rate 1Hz
Data format NMEA 0183