98/92.5 dB Stereo Codec with Class D Headphone Driver

The WM8985 is a low power stereo codec designed for portable multimedia applications requiring the lowest possible power consumption and high quality audio. The device integrates pre-amps for stereo differential mics and includes Class D and Class AB drivers for headphone and differential or stereo line output. Advanced DSP features include a five-band equalizer and 3D enhancement, an ALC/limiter for the microphone or line input through the A/D converter and a digital playback limiter. Other programmable filtering functions are available in the ADC path. Highly flexible mixing capabilities enable many new application features, with the option to record and playback any combination of voice, line inputs and digital audio. The WM8985 digital audio interface can operate in master or slave mode, while an integrated PLL provides support for all commonly used clocking schemes in portable devices.


Mono/Stereo Codecs


Stereo Codec:

  • DAC SNR 98 dB, THD -84 dB (‘A’ weighted @ 48kHz)
  • ADC SNR 92.5 dB, THD -83 dB (‘A’ weighted @ 48kHz)
  • Headphone driver with ‘capless’ option
  • 40mW/channel output power into 16ohm / 3.3V AVDD2
  • Class D headphone driver
  • Class AB headphone / line driver
  • PSRR 70 dB at 217Hz
  • Stereo, mono or differential line output

Mic Preamps:

  • Stereo differential or mono microphone interfaces
  • Programmable preamp gain
  • Pseudo-differential inputs with common mode rejection
  • Programmable ALC / noise gate in ADC path
  • Low-noise bias supplied for electret microphones

Other Features:

  • Enhanced 3-D function for improved stereo separation
  • Digital playback limiter
  • 5-band equalizer (record or playback)
  • Programmable ADC high pass filter (wind noise reduction)
  • Programmable ADC notch filter
  • Aux inputs for stereo analog input signals or ‘beep’
  • PLL supporting various clocks between 8MHz-50MHz
  • Sample rates supported (kHz): 8, 11.025, 16, 12, 16, 22.05, 24, 32, 44.1, 48
  • Low power, low voltage
  • 2.5V to 3.6V analog supplies
  • 1.71V to 3.6V digital supplies
  • 5x5mm 32-lead QFN package

Parametric Specifications

Channels In 2
Channels Out 2
DAC THD+N (dB) -84
ADC THD+N (dB) -83
Package 32 QFN

Technical Documents

WM8985 Product Datasheet

Feb 1, 2013, v4.7 : 1487 Kb

WM8985 Product Flyer

Jan 1, 2006, n/a : 231 Kb

Design Resources

WAN_0197 Improving the PSRR in Wolfson CODECs

Jun 1, 2008, WAN0197 rev 1.0 : 130 Kb

WAN_0140 ALC for Portable Applications

Mar 1, 2007, WAN0140 rev 1.2 : 436 Kb

WAN_0178 Suggested ALC Settings for Portable Devices

Feb 1, 2007, WAN0178 rev 1.0 : 81 Kb

Class D Amplifiers Empower Mobile Multimedia

Sep 1, 2006, Rev 1.0 : 144 Kb

Class D Basics

Sep 1, 2006, Rev 1.0 : 67 Kb

WAN_0181 Class D Headphone Filter Component Selection

Aug 1, 2006, WAN0181 rev 1.0 : 112 Kb

Class D Audio Design Tips

Jan 1, 2006, n/a : 325 Kb

Software and Tools


v3.8.1.2 : 40.3 Mb


Comprehensive Solutions