ZHCSCB3D March 2014 – March 2018 PCM1860 , PCM1861 , PCM1862 , PCM1863 , PCM1864 , PCM1865
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The PCM186x supports analog and digital microphones. Analog signals are treated the same way as line-level signals, except for the requirement for mic bias. Digital microphone Inputs (PDM inputs) use GPIOs on the device. Two-channel ADC variants of the PCM186x family can support two digital microphones using a single data pin and a single clock pin. The 4-channel variants can support up to 4 digital microphones (2 data pins).
The PCM1860 and PCM1861 offer three pin-selectable gain options, 0 dB, 12 dB, or 32 dB.
The PCM1862, PCM1863, PCM1864, and PCM1865 offer programmable gain options from –12 dB to +32 dB with –0.5-dB step intervals.
Digital microphones typically have a PDM output that can be brought into an ADC digital decimation filter. PDM microphones require power and a clock. Power should be handled from an external source.
Digital microphone mode gain can be added in the digital PGA and in the mixer. In digital microphone mode, the PCM1862 and PCM1863 offer up to 18-dB gain (mixer only); whereas, the PCM1864 and PCM1865 offer up to 30-dB gain (18 dB from mixer and 12 dB from digital PGA).
On the PCM1864 and PCM1865, a 2-channel digital mic + 2-channel ADC mode is possible. With the PCM1862 or PCM1863, four channels are only possible with a ADC + I2S input configuration.