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
50
Ω
impedance
ANT_DIV
35
Diversity antenna
AI
50
Ω
impedance
ANT_GNSS
47
GNSS antenna
AI
50
Ω
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