EVA-8M and EVA-M8 series - Hardware Integration Manual
UBX-16010593 - R06
Design-in
Page 21 of 47
Early Production Information
Calculation of the micro strip for RF input
The micro strip / coplanar waveguide must be 50
Ω
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.
2.11
Layout
This section provides important information for designing a reliable and sensitive GNSS system.
GNSS signals at the surface of the earth are about 15 dB below the thermal noise floor. Signal loss at
the antenna and the RF connection must be minimized as much as possible. When defining a GNSS
receiver layout, the placement of the antenna with respect to the receiver, as well as grounding,
shielding and jamming from other digital devices are crucial issues and need to be considered very
carefully.
2.11.1
Footprint
Figure 5: Recommended footprint (bottom view)
Units are in mm.
2.11.2
Paste mask
The paste mask
shall be 50 µm smaller than the copper pads with a paste thickness of 100 µm.
Pin
1
Pin36
