Low-power stereo codec integrates Class D speaker driver

Edinburgh, UK—Designed to extend playback time for audio enabled portable devices, Wolfson Microelectronics' second device in its stereo chip line is being promoted as the industry's lowest power codec.

The WM8961 builds on the foundation of Wolfson's WM8903 codec, packing in the same technology along with an additional integrated high power Class D stereo speaker driver. This enhancement extends Wolfson's low power audio products into applications that require high performance speaker driver functionality, including mobile internet devices (MID), handheld gaming and portable media players (PMP).

The WM8961's integrated charge pump provides a ground-referenced output when driving headphone loads. This removes the need for DC-blocking capacitors and enables savings in PCB space and the audio subsystem BOM. The WM8961 also uses Wolfson's proprietary Class W amplifier technology, featuring an adaptive dual drive charge pump and DC servo circuit architecture. This intelligently optimizes efficiency and power consumption during playback and enables the headphone amplifier to deliver up to 30 mW into a 16 Ω load at 1% THD+N.

The WM8961's stereo filter-less class D speaker driver provides 1W per channel into 8 Ω loads at <1% THD+N with a 5 V supply. Low leakage, an excellent power supply rejection ratio (PSRR) and pop/click suppression mechanisms also allow direct battery connection to the speaker supply. Flexible speaker boost settings allow speaker output power to be maximized while minimizing other analog supply currents.

Pricing: $1.95 in 1000K volumes.
Availability: Sampling now in an ultra thin 32-pin 5x5x0.9 mm QFN package.
Datasheet: WM8961.

Wolfson Microelectronics,

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