Power management unit and stereo audio interface that integrates a high-quality audio codec and multiple power supplies precisely adapted to the requirements of an MCU-based multimedia system. Operating from a single 2.9V to 5.5V power supply, it provides precisely calibrated voltages to other system components and enables these components to be powered down selectively to reduce power consumption. High-quality audio is provided by multiplexing the stereo inputs from two microphones, a line in and an auxiliary input, and providing stereo output for headphones or an external speaker amplifier. The audio inputs can be channeled directly to the output or digitized and transferred to the MCU for recording or processing. In playback mode, digital signals originating from the MCU are converted to high-fidelity analog for output.