Layout Guidelines - Quectel EC21 Series Hardware Design

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Accuracy
CEP-50
(GNSS)
NOTES
1. Tracking sensitivity: the lowest GNSS signal value at the antenna port on which the module can keep
on positioning for 3 minutes.
2. Reacquisition sensitivity: the lowest GNSS signal value at the antenna port on which the module can
fix position again within 3 minutes after loss of lock.
3. Cold start sensitivity: the lowest GNSS signal value at the antenna port on which the module fixes
position within 3 minutes after executing cold start command.

4.3. Layout Guidelines

The following layout guidelines should be taken into account in your design.

Maximize the distance among GNSS antenna, main antenna and the Rx-diversity antenna.

Digital circuits such as USIM card, USB interface, camera module, display connector and SD card
should be kept away from the antennas.

Use ground vias around the GNSS trace and sensitive analog signal traces to provide coplanar
isolation and protection.

Keep 50 ohm characteristic impedance for the ANT_GNSS trace.
Please refer to Chapter 5 for GNSS antenna reference design and antenna consideration.
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