Filter Routing; Filter Guidelines - Texas Instruments CC3100 SimpleLink Wi-Fi User Manual

Layout Guidelines
Sr No Guidelines
1 Route the RF lines at the input and output of the filter using a coplanar
waveguide (CPW) with ground structure. This structure offers the best
isolation between input and output due to reduced field fringing.
2 Use via stitching along the RF trace to reduce emissions and keep the fields
confined to the trace boundary.
3 Use a Zo of 50 Ω only with a tolerance of 10%. Use the stack-up and the
trace width provided for reference in the PCB design rules.
4 Add multiple ground vias for the filter ground pads as close as possible.
Minimum of 2 per GND pad is recommended.
5 To achieve the specifications of the filter attenuation, the minimum isolation
between input and output ports of the filter must be at least 60 dB. (Measured
without filter)
6 In case a conducted test is required on the PCB, TI recommends adding a
U.FL connector or a Murata switch type connector (MM8030 series).
14
CC3100 and CC3200 SimpleLink™ Wi-Fi
Layout Guidelines
Figure 8. Filter Routing
Table 7. Filter Guidelines
®
and Internet of Things Solution
Copyright © 2014–2018, Texas Instruments Incorporated
Filter
Notes
CPW with GND and via stitching can be
accurately simulated using 3D EM tools
like EESOF.
SWRU370B – June 2014 – Revised August 2018
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