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Codec chip targets VoIP telephony

A Wolfson Microelectronics product story

Edited by the Electronicstalk editorial team Nov 23, 2004

The WM8510 mono codec is the first product from Wolfson Microelectronics specifically designed for voice over Internet protocol (VoIP) devices and digital telephones.

The WM8510 mono codec is the first product from Wolfson Microelectronics specifically designed for voice over Internet protocol (VoIP) devices and digital telephones.

The WM8510 delivers high-quality audio performance at low cost.

A low power, highly integrated device, the WM8510 significantly reduces design costs and external component requirements.

According to Juniper Research, VoIP will account for over 12% of all telephony revenues by 2009 as VoIP evolves from being a replacement service for the public switch telephone network (PSTN) to a new converged service for the home and business user.

"The WM8510 delivers the performance and features that the fast-growing VoIP market demands", said John Crawford, Product Manager, Wolfson Microelectronics.

"It is designed specifically for digital telephone applications such as desktop phones, conference speakerphones and mobile telephone hands-free kits".

The WM8510 includes a driver for a speaker or headset, two separate microphone inputs (eg handset and speakerphone) and two dedicated analogue audio outputs with volume control.

Advanced sigma delta convertors are used along with digital decimation and interpolation filters to give high quality audio at sample rates from 8 to 48Ksample/s.

Additional digital filtering options are available in the ADC path, as is an advanced automatic level control (ALC) function with noise gate.

An on-chip PLL is provided to generate the required master clock from an external reference clock.

The PLL clock can also be output if required elsewhere in the system.

The WM8510 has a standard audio interface supporting transmission of audio data to and from the chip.

The interface supports a number of audio data formats including mu-law and alpha-law, PCM, IIS and DSP mode, and can operate in master or slave modes.

The WM8510 operates at supply voltages from 2.5 to 3.6V, although the digital core can operate at voltages down to 1.62V to save power.

The speaker and mono outputs use a separate supply of up to 5V, which enables increased output power if required.

Different sections of the chip can also be powered down under software control by way of the selectable two- or three-wire control interface.

The WM8510 is available in a 28-pin SSOP package.