UM980 User Manual
14
Hardware Design
UC-00-M32 EN R1.0
UM980
ANT_IN
ANT
VCC_RF
GND
C2
ANT_BIAS
L1
C1
D1
D2
Figure 3-1 UM980 External Antenna Feed Reference Circuit
Remarks:
L1: feed inductor, 68 nH RF inductor in 0603 package is recommended
C1: decoupling capacitor, recommended to connect two capacitors of
100 nF/100 pF in parallel
C2: DC blocking capacitor, recommended 100 pF capacitor
It is not recommended to take VCC_RF as ANT_BIAS to feed the antenna (VCC_RF is
not optimized for anti-lightning strike, anti-surge and over current protection due to
the compact size of the module)
D1: ESD diode, choose the ESD protection device that supports high frequency
signals (above 1000 MHz)
D2: TVS diode, choose the TVS diode with appropriate clamping specification
according to the requirement of feed voltage and antenna voltage
