User Manual

GM862-QUAD / PY Hardware User Guide

1vv0300748 Rev. 5 - 20/09/07

NOTE: In the unbalanced application the capacitor C3 shall be > 200nF otherwise the frequency

response will be cut at low band frequencies (down to 300Hz). This capacitor can be placed

close to the MIC- pad (MIC_HF- or MIC_MT- depending on the audio path chosen) or if

possible it should be placed close to the shielded cable connector. If the ground return path is

well designed, then it is possible to eliminate the C3 capacitor, provided the buffer is close to

the mic. input.

NOTE: The cable to the microphone should be shielded.

NOTE: The microphone changes with the value of R2. Usually the microphone sensitivity is

characterized with 2kΩ biasing resistance, so try to keep the value of R2 around 2kΩ. For mic.

characteristics refer to the manufacturer.