Edinburgh, UK – 22 January 2007 – Wolfson Microelectronics plc (LSE:WLF.L) has announced the WM8991 audio CODEC featuring a dual mode, 1W speaker driver with the flexibility to switch between Class AB and Class D operation. The WM8991 is based on Wolfson’s ‘Audio Hub’ concept which is enabling a new generation of feature-rich multi-media handsets which can mix and select from multiple audio sources including voice, radio, music, mobile TV and Wi-Fi.

Offered in compact 5x5mm BGA packaging and with 98dB SNR performance, the WM8991 supports the signal switching, audio conversion and voice mixing requirements for next-generation mobile phones, allowing designers to add new features quickly and enabling flexible new end-user modes such as viewing TV during a voice call. The digital core consumes less power than similar devices and can be as low as 5mW during a voice call.

The innovative ability to select Class AB or Class D operation allows handset designers to deploy filterless Class D technology into a wider range of increasingly diverse handheld form factors where restrictions such as noise and interference previously demanded a Class AB driver topology. System designers may select the most appropriate mode of operation for the anticipated usage scenario, allowing battery life for the end user to be maximised.

Eight analogue inputs and nine pop-free analogue outputs eliminate the need for external input or output switches. This means that designers can quickly integrate a second processor, such as the digital TV tuner, without tri-stating the main processor interface. All line-in and line-out ports are fully balanced and feature differential signalling, allowing high-speed cellular handsets to deliver high performance, noise-free audio. General Purpose IOs permit designers to implement button or accessory detect with programmable button debounce to support handset differentiating features, as well as added-value capabilities such as processor wake-up from low-power sleep mode. There is also a dedicated MIC BIAS input pin supporting eight programmable current detect levels for enhanced accessory support. 

The WM8991 features a fully differential headphone output, which eliminates external capacitors to save more space and minimise the bill of materials, reduce noise and crosstalk and improve bass quality. Phantom ground design, as well as the provision of an AC coupled mode, allows the headphone output to drive an additional ear speaker. 

Advanced voice features include digital sidetone, allowing low frequency noise, such as wind noise and mechanical vibration, to be digitally filtered from the attenuated voice feedback signal. 

Availability
The WM8991 is available for sampling now. 

About Wolfson Microelectronics
Wolfson Microelectronics plc is a leading global provider of high performance, mixed-signal semiconductors for digital consumer electronics applications. 

Renowned worldwide for its audio and imaging technologies, Wolfson devices can be found at the heart of many of the world’s highest profile consumer products, including mobile phones, MP3 players, gaming consoles, DVD players, DVD-RW, LCD-TV and multi-function peripherals. If a digital product can capture an image or play a sound, Wolfson’s vision is to supply a product that will allow it to perform these tasks better. 

Headquartered in Edinburgh, UK, Wolfson has sales and engineering offices in the USA, Japan, China, Taiwan, Korea and Singapore. Wolfson Microelectronics plc is listed on the London Stock Exchange (LSE: WLF.L). 

For more information about Wolfson Microelectronics, please visit www.wolfsonmicro.com
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