Codec with Headphone Driver

The WM8731 is a low power stereo codec with an integrated headphone driver. Stereo line and mono microphone level audio inputs are provided, along with a mute function, programmable line level volume control and a bias voltage output suitable for an electric type microphone. Digital audio input word lengths from 16-32 bits and sampling rates from 8 kHz to 96 kHz are supported. Stereo audio outputs are buffered for driving headphones from a programmable volume control, line level outputs are also provided along with anti-thump mute and power up/down circuitry. The device is controlled via a 2 or 3 wire serial interface. The interface provides access to all features including volume controls, mutes, de-emphasis and extensive power management facilities.



Portable Codecs


  • Stereo audio codec with integrated headphone driver (50㎽ on 16Ω @ 3.3V)
  • 1.42 – 3.6 V digital supply
  • 2.7 – 3.6 V analog supply (standard)
  • 1.8 – 3.6 V analog supply (’L’ version)
  • Playback mode power consumption < 18㎽
  • 100 dB SNR (‘A’ weighted @ 48kHz) DAC
  • 90 dB SNR (‘A’ weighted @ 48kHz) ADC
  • Sampling frequency: 8 – 96 kHz
  • Main or secondary clocking mode
  • USB clocking mode can generate all common MP3 sample rates (incl. 441.kHz) directly from USB clock
  • Output volume and mute controls
  • Microphone input and electret bias with side tone mixer
  • Selectable ADC high pass filter
  • 2 or three-wire MPU serial control interface
  • Programmable audio data interface modes
  • 28-Pin SSOP package

Parametric Specifications

DACs 2
ADCs 2
DAC THD+N (dB) -84
ADC THD+N (dB) -76
Sample Rate (kHz) 96
Analog Power Supply (V) 2.7-3.6
Power Consumption (mW) 12-22
Package 28 QFN


Comprehensive Solutions