Product Info

LTE Module Series
EG91 Hardware Design
EG91_Hardware_Design 63 / 93
In order to ensure RF performance and reliability, the following principles should be complied with in RF
layout design:
 Use impedance simulation tool to control the characteristic impedanceof RF tracesas 50Ω.
 The GND pins adjacent to RF pins should not bedesigned as thermal relief pads, and should be fully
connected to ground.
 The distance between the RF pinsand the RFconnector should be as short as possible, and all the
right angle traces should be changed to curved ones.
 There should be clearance area under the signal pin of the antenna connector or solder joint.
 The reference ground of RF traces should be complete. Meanwhile, adding some ground viasaround
RF traces and the reference ground could help to improve RF performance. The distance between
the ground vias and RF traces should be no less than two times the width of RF signal traces (2*W).
For more details about RF layout, please refer to document [5].
5.2. GNSS Antenna Interface
The GNSS antenna interface is only supported on EG91-NA/-NS/-V/-EC. The following tables show pin
definition and frequency specification of GNSS antenna interface.
Table 26: Pin Definition of GNSS Antenna Interface
Pin Name Pin No. I/O Description Comment
ANT_GNSS
(EG91-NA/-NS/-V/-EC)
49 AI GNSS antenna 50Ωimpedance
Table 27: GNSS Frequency
Type Frequency Unit
GPS 1575.42±1.023 MHz
GLONASS 1597.5~1605.8 MHz
Galileo 1575.42±2.046 MHz
BeiDou 1561.098±2.046 MHz
QZSS 1575.42 MHz
A reference design of GNSS antenna is shown as below.