AMY-6M - Hardware Integration Manual
UBX-17021971 – R07
Design-in
Page 33 of 57
2.11
Layout design-in checklist
Follow this checklist for the layout design to get an optimal GPS performance.
Layout optimizations (
Section 2.12
Is the AMY-6M placed according to the recommendation in
Section 2.12.3
Is the Grounding concept optimal?
Has the 50 Ohm line from antenna to AMY-6M (micro strip/coplanar waveguide) been kept as short as
possible?
Assure low serial resistance in V_DCDC power supply line (choose a line width >400um)
Keep power supply line as short as possible
Design a GND guard ring around the optional RTC crystal lines and GND below the RTC circuit.
Add a ground plane underneath the GPS module to reduce interference. Especially for the RF input line.
For improved shielding, add as many vias as possible around the micro strip/coplanar waveguide, around the
serial communication lines, underneath the GPS module etc.
Calculation of the micro strip for RF input
The micro strip/coplanar waveguide must be 50 Ohms and be routed in a section of the PCB where minimal
interference from noise sources can be expected. Make sure around the RF line is only GND as well as under
the RF line.
In case of a multi-layer PCB, use the thickness of the dielectric between the signal and the 1st
GND
layer
(typically the 2nd layer) for the micro strip/coplanar waveguide calculation.
If the distance between the micro strip and the adjacent
GND
area (on the same layer) does not exceed 5
times the track width of the micro strip, use the “Coplanar Waveguide” model in AppCad to calculate the
micro strip and not the “micro strip” model.
