WM8955 datasheet(14/43 Pages) WOLFSON

14 / 43 page

WM8955L

Product Preview

Product Preview Rev 0.4 May2003

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 I

2S,

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.

WM8955 датащи(PDF) 14 Page - Wolfson Microelectronics plc