Stereo Codec is optimized for portable audio applications.

Press Release Summary:

Available in 40-pin, 5 x 5x 0.55 mm QFN package for space-constrained applications, Model WM8903 features SmartDAC(TM) low-power DAC capacitor switching architecture to enable DAC to headphone power consumption of just 4.4 mW and includes capability for programmable performance vs. power profiles, allowing system designers to optimize for each usage scenario. It also includes Class W amplifier technology featuring adaptive dual drive charge pump and DC servo circuit architecture.

Original Press Release:

Wolfson's Next-Generation Codec for Portable Devices Extends Audio Playback Time up to 40 Hours

Edinburgh, UK - June 9th 2008 - Wolfson Microelectronics (LSE: WLF.L) today announces the launch of its WM8903 CODEC - the first in the next generation of ultra low power audio devices. Packed with innovative new technology, the WM8903 is designed to dramatically extend playback time for audio enabled portable devices, such as portable media players, multimedia handsets and handheld gaming systems.

The WM8903 ultra low power codec delivers Wolfson high performance audio and market leading power consumption in an ultra slim, low profile form factor to meet the demanding needs of today's multimedia portable devices. The WM8903 enables designers to push product design boundaries and develop compelling, highly differentiated end products.

The WM8903 features Wolfson's new SmartDAC(TM) technology, a unique low-power DAC capacitor switching architecture. This enables DAC to headphone power consumption of just 4.4 mW and includes a capability for programmable "performance vs. power" profiles, allowing system designers to optimize for each usage scenario, such as docked or on the move.

The WM8903 also includes Wolfson's Class W amplifier technology, an evolution of class G and H, featuring an adaptive dual drive charge pump and DC servo circuit architecture. The Class W headphone amplifier technology intelligently tracks the actual music signal level and uses an adaptive dual drive charge pump to optimize power dissipation. The WM8903 can also operate from a common 1.8 V supply for both analog and digital power rails. With a significant power supply rejection ratio (PSRR), the WM8903 can share noisy power supply rails with other digital devices with no performance compromise. This architecture not only optimizes power consumption but also eliminates the need for large DC blocking headphone capacitors, enabling significant savings in PCB space and the audio subsystem bill of materials (BOM). It also brings additional audio benefits through an improved bass response.

Engineered to sound better, the WM8903 further enhances audio performance by integrating Wolfson's innovative SilentSwitch(TM) technology which incorporates sophisticated clamp and sequencer circuitry to extend its pop & click suppression. Unwanted noise at the headphone amplifier output is reduced during power-up and mute/un-mute by clamping the output to ground.

Using an integrated sequencer with programmable delay times to power-up/power-down parts of the WM8903 significantly reduces pops & clicks and reduces time to market by lowering software driver development time.

When in record mode the WM8903 implements an advanced dynamic range controller (DRC) which optimizes recorded sound quality. Wolfson has also implemented a quick release impulse noise filter that enhances the intelligibility of recorded sound in the presence of loud impulse noises. This noise filter can precisely recognize the difference between sudden, unwanted noises and actual rises in the desired signal being recorded.

The WM8903 provides the core for a distributed ultra low power audio subsystem. Its inherent flexibility offers the system designer the option to use the latest digital output microphones, such as Wolfson True Mics technology, through an integrated digital microphone interface. This is complemented by six highly configurable analog inputs for stereo microphone recording, as well as connection to a variety of analog audio sources. Additional audio outputs also allow seamless connection with efficient Class D speaker amplifiers, such as Wolfson's WM9001, for use in portable media platforms with speakers.

Peter Frith, CTO at Wolfson comments, "The WM8903 is truly a next generation ultra low power device, enabling a remarkable extension in device audio playback time. With the WM8903, designers can create portable devices with playback times up to 40 hours on a single charge." Peter Frith continues, "The WM8903 is packed with innovative new technologies and is a great example of the Wolfson AudioPlus(TM) product line, interlacing elements of Pure Audio, Smart Power, True Mics and Enhanced Soundware."

Availability and pricing:
The WM8903 is available for sampling now in a thin 40-pin, 5x5x0.55 mm QFN package, well suited for space-constrained portable applications. It is priced at $1.80 per unit in volumes of 10,000 units.

WM8903 customer evaluation boards with the Wolfson Interactive Setup and
Configuration Environment (WISCE) are available to enable rapid device evaluation and development. The WISCE software provides an interactive register map interface allowing control and overview of the device settings as well as outputting fully commented C-code.

Technology Overview:

New technologies reduce power consumption, extend playback time and enhance high performance audio.

Wolfson Microelectronics has developed a technology platform which delivers high performance audio at ultra low power levels. The SmartDAC(TM), Class W amplifier technology and SilentSwitch(TM) technologies announced today coincide with the launch of Wolfson's new WM8903 codec. When combined, these innovations deliver world-class, high-performance audio and market leading power consumption, enabling portable device designers to take battery life to new levels. These proprietary new technologies provide the foundation for Wolfson's next generation of ultra low power audio devices.

Wolfson's unique DAC capacitor switching architecture drives down the inherent DAC power consumption to market-leading, ultra low levels. High PSRR means audio performance is maintained even when powered by noisy switched mode power supplies. This eliminates the need for a dedicated audio supply, meaning a smaller PCB footprint and lower bill of materials. SmartDAC(TM) also includes a capability for programmable "performance vs. power" profiles, where fine grain control of power and audio performance give the system designer flexibility in meeting even the most demanding power budgets. SmartDAC(TM) delivers the world renowned Wolfson sound at a whole new level of ultra low power consumption.

Class W adaptive dual drive headphone driver
With its proprietary Class W amplifier technology containing an adaptive dual drive charge pump and DC servo architecture, Wolfson has developed an innovative approach to capless output driving. Designers no longer have to compromise on power consumption, board space or audio quality when using a ground referenced output driver. Evolved from Class G/H amplifier techniques, this innovative technology intelligently forecasts and optimizes amplifier efficiency for ultra low power consumption in headphone playback mode based on music content signal levels. Wolfson's headphone driver technology offers a substantial reduction in overall power usage because headphone playback is one of the most frequent usage modes.

Wolfson has enhanced its pop & click suppression functionality with clamp & sequencer technology. Unwanted noise at the headphone amplifier output is reduced during power-up and power-down by the use of sophisticated clamping circuitry, which holds the headphone output to ground during power up. The sequencer technology integrated into SilentSwitch(TM) enables further advances in pop & click suppression during power up/power down. With the integrated register write sequencer, the audio path setup can be pre-loaded and executed by the control sequencer with programmable delay times to reduce common pops and clicks and enhance the listening experience. Furthermore, the sequencer also significantly reduces software driver development time thereby reducing time to market.

Peter Frith, CTO at Wolfson comments, "Wolfson is pushing the boundaries of world class audio and ultra low power consumption. Our next generation of devices, employing these innovative new technologies, will enable designers to enhance the user experience with high performance audio, while extending playback time to a whole new level."

About Wolfson Microelectronics
Wolfson Microelectronics plc is a leading global provider of high performance, mixed signal semiconductors to the consumer electronics market.

Wolfson is renowned for its high performance audio and ultra low power consumption, its devices are at the heart of many high profile consumer electronics products, including mobile phones, mp3 players, flat panel TVs and in-car infotainment systems. Wolfson technology enables exciting new end-user experiences by connecting the digital world to the human senses.

Headquartered in Edinburgh, UK, Wolfson has sales and engineering offices in the USA, Japan, China, Taiwan, Korea, Singapore and India. Wolfson Microelectronics plc is listed on the London stock exchange. (LSE: WLF.L) For more information about Wolfson Microelectronics, please visit: or sign up for Wolfson eNews at:

Anne Connolly
Wolfson Microelectronics plc
Tel: +44 (0) 131 272 7000

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