Audio codecs increase power efficiency

Stereo audio codecs are slated for battery-operated applications, including digital still cameras and portable media players.

Texas Instruments has introduced two new stereo audio codecs for battery-operated applications, including digital still cameras and portable media players.

Designed to extend battery life by lowering power consumption, the PCM3793 and PCM3794 audio codecs offer outstanding 7mW playback with a signal-to-noise ratio (SNR) of 93dB.

The PCM3793 audio codec further increases power efficiency by integrating TI's leading Class-D amplifier technology which is capable of driving 700mW of output power per channel into an 8ohm load.

To complement the PCM3793, the PCM3794 has no speaker outputs, providing manufacturers with the flexibility to use an external amplifier, if desired.

"The efficiency of TI's Class-D amplifiers makes them critical to the success of any battery-powered audio system", said Susie Inouye, Analyst, Databeans.

"TI provides not only low power and noise, but also the value-added features manufacturers need to drive down system costs".

TI's PCM379x codecs offer key features that meet the specific needs of portable consumer audio OEMs, including: a notch filter with programmable centre frequencies (without a notch filter, digital camera manufacturers have had to disable zooming during video recording to prevent camera lens motor noise from disrupting the audio track); tone control, allowing OEMs to maximise audio performance for a particular application using bass, treble and mid-range equalisation effects; and 3D enhancement so that speakers that are close together can be made to seem further apart for a richer "wide stereo" effect.

An on-chip, digital audio processor keeps signal processing in the digital domain, giving OEMs more control, lower noise and better power efficiency.

The PCM379x codecs also can be operated with only one power supply, whereas other codecs require an additional power supply for analogue and digital circuitry.

An integrated cap-less headphone driver reduces external component count and increases bass frequency response.

PCM379x audio codecs support standard interfaces for audio (I2S, L-R justified, DSP) and control (I2C, SPI), as well as multiple single-ended and differential inputs and outputs (six inputs for both, with five outputs for the PCM3793 and three for the PCM3794).

Additionally, inputs are selectable, and outputs can be mixed, giving designers control over a wide range of applications.

"With exceptionally low playback power and integrated features in the PCM379x codecs, TI has struck the optimal balance of power and performance that our customers require", said Greg Davis, High Performance Portable Audio Marketing Manager, Texas Instruments.

"For instance, it's exciting that we can help enable features, such as zooming while recording video on a digital still camera".

"Additionally, these devices integrate equalisation and audio effects that can be helpful for portable media players".

The PCM3793 and PCM3794 stereo audio codecs are sampling now and is expected to be in production in September 2006.

Both are packaged in a standard 32-pin 5 x 5mm QFN package.

Pricing for the PCM3793 is $4.50 and the PCM3794 is $4.25, each in quantities of 1000 units.

A turnkey evaluation module is expected to be available in October 2006 that includes a PC-based interface for easily programming PCM379x devices.

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