RoyalTek RET-3570LP - Manual (Page 8)

RoyalTek Confidential
6
RET-3570LP User Manual
26 Operating temperature -40 ~ 85℃
27 Humidity ≦ 95%
1.6 Application Circuit
Reference:
Note:
(1) Ground Planes:
RET3570LP GPS receiver needs two different ground planes.
These pins(13、15、16、18) should be connected to analog ground.
These pins(2、10、30) should be connected to digital ground.
(2) Serial Interface:
(I)The TXA pin is recommended to pull up (10KΩ). It can increase the stability of
serial data .
(II) The TXB pin is recommended to connect to serial resistance(220Ω) and pull
up (10KΩ), if use the DGPS output.
If the DGPS output is not used, it won’t connect anything.
(III) The RXB pin is recommended to connect to serial resistance(220Ω), if the DGPS
output is used.
If the DGPS output is not used, it won’t connect anything.
(3) Backup Battery:
It’s recommended to connect a backup battery to V_RTC_3V3 in order to enable the warm
start and hot start features of the GPS receiver. If you don’t intend to use a backup battery,
connect this pin to GND or float it.
If you use a backup battery, you should add a bypassing capacitor (10uF) at V_RTC_3V3
pin to reduce noise and increase the stability.
(4) GPS_RF_IN:
Connecting to the antenna has to be routed on the PCB. The transmission line must control