Example Of A Differential Mic Connection With An Lc Filter; Example Of A Differential Mic Connection Without An Lc Filter - Sierra Wireless WISMO228 Product Technical Specification & Customer Design Manuallines

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Audio quality can be very good without L1, L2, C2, C3 and C4 depending on the design. But if there

is EMI perturbation, this filter can reduce the TDMA noise. This filter (L1, L2, C2, C3 and C4) is not

mandatory, and if not used, the capacitor must be removed and the coil replaced by a 0Ω resistor as

shown in the following schematic.

The capacitor C1 is highly recommended to eliminate TDMA noise and must be close to the

microphone.

The following table lists the recommended components to use in implementing a differential MIC

connection without an LC filter.

WA_DEV_W228_PTS_002

Figure 19. Example of a Differential MIC Connection with an LC Filter

Figure 20. Example of a Differential MIC Connection without an LC Filter

Rev 001

Product Technical Specification &

Customer Design Guidelines

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