PCM1809EVM has two onboard differential microphones that can be routed to the inputs with jumpers. The microphones require a bias be applied to MPWR. MPWR can be tied to AVDD on J4, or to MICBIAS if using a device that supports this feature. Note that PCM1809 does not have an integrated MICBIAS and this option is provided for future devices that can incorporate this feature. The following jumpers need to be installed to use the onboard mics: J4, J11,J12, J14, J15, J16, and J21.

If the onboard mics are used, then leave the J1 and J2 headers unconnected to preserve the microphone performance.

Figure 2-3 PCM1809 Onboard Microphones