2.11 Analog Microphone Inputs

The differential microphone input circuit and the placement rules are listed below:

  • The DC blocking capacitors (C21 and C34) are placed as close as possible to IS2083BM.
  • The MIC_BIAS filtering components (R6 and C22) are placed close to the microphone.
  • The microphone and signal paths of microphone must be routed on same layer.
  • Components on differential paths (MICP1, MICN1, MIC_P1 and MIC_N1) must be placed close to each other to reduce common mode noise.
Note:
  1. If single microphone is used, change R10 from 2 kΩ to 0Ω.
  2. Connect MICP1 with microphone positive side and MICN1 to microphone ground.
Figure 2-8. Reference Analog Microphone Inputs Schematic and PCB Routing