WM9082: 3W Mono Class D Speaker Driver with PDM Input


The WM9082 is a high-performance sigma-delta Class D speaker driver. Audio input is supported using a stereo PDM interface; clock and control-code detection circuitry supports all of the audio and control functions via a 2-wire interface.

The digital audio interface provides excellent noise immunity, eliminating traditional input-filtering components. The flexible 2-wire interface minimises the PCB footprint and simplifies software development.

The combined audio and control interface configuration is ideal for enabling the WM9082 to be located close to the speaker; this reduces the length of the output connections, giving good EMC performance and removing the need for output filter components.

The sigma-delta architecture provides good power efficiency and improved EMI performance with respect to traditional PWM Class D designs.

A first-order high-pass filter can be selected on the input signal to remove DC offsets and help to prevent speaker damage. Other features include a low-power mute state, and output slew-rate control.

Short-circuit and thermal protection is provided.

The WM9082 is supplied in a 9-ball 1.56 x 1.46mm CSP package, with 0.5mm ball pitch.


  • Sigma-Delta Class-D speaker driver
    -  92dB SNR - 'A' weighted
    -  2.5W into 4Ω (5V supply, 1% THD)
    -  1.3W into 4Ω (3.6V supply, 1% THD)
    -  1.25W into 8Ω (5V supply, 1% THD)
    -  650mW into 8Ω (3.6V supply, 1% THD)
  • Stereo PDM digital audio input
  • Supports 32kHz, 44.1kHz, 48kHz sample rates (128fs input)
  • Automatic Left/Right channel selection
  • First-order high pass filter (HPF)
  • RF noise suppression
  • Pop and click suppression
  • Programmable output slew rates for low EMI
  • Short-circuit and thermal protection
  • 9-ball CSP package