LC-FilterApplication Note AN028 LC filter with improved high-frequency attenuation By K. H. Torvmark Keywords LC filter Harmonics T-type filter Introduction This application note describes an improved T-type LC filter that can be used to further attenuate harmonics if a standard Pi-type filter (such as the one used in many of Chipcon’s development kits) is not sufficient. This T-type filter provides much better stop-band attenuation than a Pi-type filter due to improved insulation between input and output. Measured results for a filter for operation in the 915 MHz band are also presented. SWRA064 Page 1 of 8 Application Note AN028 Harmonics When designing an RF power amplifier, there is always a trade-off between linearity and efficiency. Since power amplifiers used in low-power radio sy……