Wednesday, 11 January 2012 15:06

AX5043 App Note: DVK-2 Module V1.0 Matching at 868 MHz

During the layout change of the 868 MHz AX5043 RF module from the DVK-1 v1.0 to DVK-2 v1.0 modules a 2nd harmonic larger than regulatory limits appeared. To be more independant of board layout we recommend to introduce a harmonic filter.

The filter is composed of CF1, CF2, CF3 and LF1. To pass ETSI EN 300 220 V2.3.1 limits the following components should be used (structure see the figure). The output power loss due to this filter is around 0.5 dB.

LF1 = 2.2 nH
CF1 = 3.6 pF
CF2 = not connected
CF3 = not connected