0433BM15A0001E Datasheet, PDF (6/27 Pages) Johanson Technology Inc. – Johanson Technology Matched Balun Filters for CC110x & CC111x

3.3.1.1 Component Placement
Design Note DN025
Figure 6. Component Placement
The component placement influences the RF performance. In the event that the reference
design [6] can not be copied then it is important to position the inductor L122 so that the
coupling effects to the Matched Balun Filter U121 are minimized as much as possible.
Experiments with placing L122 in parallel to U121 showed that coupling was evident and the
Matched Balun Filter performance was not optimum. Keep the inductor L122 at 90 degrees to
the balun as shown in Figure 6 or position it on the left side of U121 to avoid coupling to pin 6
of U121.
SWRA250A
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