WM8955L
Product Preview
DEVICE DESCRIPTION
INTRODUCTION
The WM8955L is a low power audio DAC offering a combination of high qualityaudio, advanced
features, low power and small size. These characteristics make it ideal for portable digital audio
applications such as portable music players and smartphones.
The device has a configurable digital audio interface where digital audio data is fed to the internal
digital filters and then the DAC. The interface supports a number of audio data formats including I2S,
DSP Mode (a burst mode in which frame sync plus 2 data packed words are transmitted), Left
Justified and Right Justified formats, and can operate in master or slave modes.
The on-chip digital filters perform tone control and digital volume control according to the user
setting, and convert the audio data into oversampled bitstreams, which are passed to the left and
right channel DACs. A multi-bit, low-order Σ∆ DAC architecture with dynamic element matching is
used, delivering optimum performance with low power consumption.
The DAC output signal enters an analogue mixer where analogue input signals can be added to it.
The WM8955L has a total of six analogue output pins, which can be configured as stereo line-outs,
mono line-outs, differential mono line-outs, stereo headphone outputs or differential mono (BTL)
speaker outputs.
The WM8955L includes an on-chip PLL to generate commonlyused audio rates, such as 48kHz and
44.1kHz, from system clocks found in GSM, CDMA and PDC phones and other portable systems.
To allow full software control over all its features, the WM8955L offers a choice of 2 or 3 wire MPU
control interface. It is fullycompatible and an ideal partner for a wide range of industrystandard
microprocessors, controllers and DSPs.
The design of the WM8955L has given much attention to power consumption without compromising
performance. It operates at verylow voltages, and includes the abilityto power off parts of the
circuitryunder software control, including standbyand power off modes.
Product Preview Rev 0.4 May2003
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
