Method and apparatus for substantially improving power supply rejection performance in a miniature microphone assembly

摘要

A hybrid circuit ( 300 ) for use in a miniature microphone assembly ( 100 ) reduces power supply noise on the audio signal input ( 214 ) of an impedance buffer amplifier ( 200 ) using one or both of shielding conductors 422, 424 to reduce parasitic capacitance between signal ( 418 ) and power supply ( 420 ) conductors. A ground plane ( 424 ), an interposing conductor ( 422 ) and combinations thereof are selectively placed and coupled to either ground ( 232 ) or a low impedance signal node ( 216 ) to reduce or eliminate the undesirable parasitic capacitance.