Wolfson Microelectronics Ltd. announced the release of a new generation of ACı97 audio codecs, the WM9703 and WM9704Q. Fully ACı97 Revision 2.1 compliant, these devices use the latest sigma-delta converter architecture and audio circuits to deliver greater than 95dB signal-to-noise ratio on playback. They offer the system designer unparalleled levels of integration, performance and high power for PC audio applications.

WM9704Q

WM9704Q is the Worldıs only 4-channel codec with variable rate audio. The WM9704Q sets new benchmarks for the reproduction of multi-dimensional sound in a PC environment. It combines four 18-bit DACs with an 18-bit stereo ADC, stereo inputs for line, aux, video and a pseudo-differential input for CD to minimise cross-talk. The WM9704Q also supports mono inputs for phone and dual microphone.

The replay of 5.1 audio sources such as Dolby Digital (AC-3) or MPEG 5.1 is facilitated through a simple interface to the codec. On-board GPIO pins are re-configurable to provide I²S outputs. These can be connected directly to a simple stereo DAC such as the WM8725 (also available from Wolfson) to create the ultimate surround sound experience. Additional functions include 3-D analogue sound enhancement and true line-level outputs.

WM9703

The WM9703 is a high performance Revision 2.1 compliant, 18-bit audio codec combining a stereo ADC, stereo DAC, stereo mixing and multiple inputs for stereo and mono signals. High quality CD sources are also supported with a pseudo-differential input to minimise cross-talk. Additional functions include 3-D analogue sound enhancement and true line-level outputs.

With multiple power-down modes and worldıs lowest active power consumption (<100mW), the device is ideally suited for new ıgreenı and portable PC designs.

Both devices have master/slave ID selection that support the seamless addition of modem and docking facilities and variable rate sampling for audio reducing the processor burden. The WM9703 and WM9704Q surpass the minimum performance requirements for PC99 audio and are fully operable on 3.3V or 5V or mixed 3.3/5V supplies.

About Wolfson

Regular readers will know how fond I am in getting specifications thrown around in this nasty little segment of the marketplace. I have never understood why so many manufacturers want to be told by a specification what their parts are going to do and end up having to duke it out over small additional features and, of course, price. Needless to say, the power consumption in the WM9703 stereo codec is extremely noteworthy and it will make it a top contender in the laptop computer market where the reason for high-quality still remains a mystery to me. The WM9703 is also very much priced to sell and Wolfson will do well from it.

The WM9704Q is a fascinating development. With four channels the truly bizarre audio experiences can happen within the PC. Clearly this must have been designed for a specific customer and I am looking forward to seeing how it is being used by that customer. Developing parts such as this, however, is only a first step in achieving anything like the specified performance within the PC -- a truly hostile environment for analog signals. Left in the hands of digital designers some of the reference designs that vendors produce will become the de facto layout standards.

I find Wolfson's statement to have "manufacturing facilities in the USA, Asia Pacific and Europe" extremely misleading as they are a "fabless manufacturer."