Wolfson audio DAC uses 4mW, costs $1.52

I got a press release from Wolfson about their new WM8912 audio DAC (digital to analog converter) plus headphone driver IC. The part’s SNR is 96dB typical, and THD is -86dB typical. The part can output 28mW per channel into 32Ω at <1% THD, and - 30mW per channel into 16Ω at <1% THD. The DAC only (no amp) draws 4mW of power. The output amp uses class-G— they use charge pumps to vary the amplifier’s power supply rails in order to conserves power. They call this class-W but that is just marketing—what a coincidence an amplifier class just happens to be the first letter in Wolfson.

Like most IC companies, Wolfson’s configurable parts come with a programming environment and demo boards you can hook to the USB on your computer. The demo board then takes that USB and makes it into SPI or I2C or something the chip can communicate with.

Wolfson just about owned the audio DACs in CD players and such a few years ago. Needless to say, the explosion in mobile products has been very good for Wolfson and they bring out a ton of codex (compressors-decompressors) with headphone amps and such. They also have been brought out power management parts like the innovative WM8312. It seemed strange to me at first, seeing and audio powerhouse go into power management, but it really is a clever strategy.

The brilliant thing about Wolfson being into both audio and power management is that both those subsystems have analog content and both make sense to be disintegrated from the main digital chip. If you want to listen to an FM radio in a product, wouldn’t it make sense for the power management chip to wake up the backlight and buttons when its accelerometer detects you have picked it up? Then it sees that you pressed the FM radio button, then turn on the FM radio chip, then take that output and route it to the headphone jack, There is never any need to power up the big thirsty digital processor chips, especially the baseband chip or application processor. All this means great battery life.

Now all this big-system customer chip stuff is great, but it is also great to see Wolfson get back to its roots and come out with a DAC with headphone driver too. Simple building blocks can make for more flexibility in your systems.

Other companies with cool DAC products include the Cirrus Logic folks down in Austin, and ESS over in Fremont. ESS is making super high performance DACs and ADCs. And don’t forget about the giants like NSC, TI and Analog Devices. It was Peter Henry over at ADI that explained to me how a power management chip can orchestrate the whole used experience and maybe never have to turn on those power hungry digital chips.