Design Note DN025
3.3
3.3.1
JTI Matched Filter Balun Reference Designs
JTI Matched Filter Balun for 868 MHz and 915 MHz (Dual Band)
Johanson Technology has developed a solution with a chip balun that is especially matched
for the CC110x and CC111x chips. Please refer to Appendix A [6.1] for data sheet of the
matched balun filter component (the full specification is available from the Johanson
Technology web site [4]).
The JTI matched balun filter solution [6] implemented on the CC1101 868/915 MHz JTI Balun
reference design consists of the Matched Balun Filter and an external LC filter which is valid
for all CC110x and CC111x. The need of the LC filter is discussed in more detail in Section
Figure 5. JTI Reference Design for the CC110x and CC111x 868/915 MHz (no decoupling
capacitors shown)
Referring to Figure 5, U121 is the JTI Matched Balun Filter 0896BM15A0001. Inductor L122
is 5.6 nH and capacitor C123 is 1.8 pF; these two components form the LC filter. C124 is a
DC blocking capacitor and should be NPO type to minimize losses; recommended value of
100 pF. The DC block is only needed when there is a DC path in the antenna. Recommended
part numbers from Johanson Technology for the inductor (L122) is L-07C5N6SV4 and the
capacitor (CC123) is 500R07S1R8BV4.
SWRA250A
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