Production Data
WM8711BL
DEVICE DESCRIPTION
INTRODUCTION
The WM8711BL is a low power audio DAC designed specifically for portable audio products. Its
features, performance and low power consumption make it ideal for portable MP3, CD and mini-disc
players.
The WM8711BL includes line and headphone outputs from the on-board DAC, configurable digital
audio interface and a choice of 2 or 3 wire MPU control interface. It is fully compatible and an ideal
partner for a range of industry standard microprocessors, controllers and DSPs.
The on-board digital to analogue converter (DAC) accepts digital audio from the digital audio
interface. Digital filter de-emphasis at 32kHz, 44.1kHz and 48kHz can be applied to the digital data
under software control. The DAC employs
a high quality multi-bit high-order oversampling
architecture to again deliver optimum performance with low power consumption.
The DAC outputs and Line Inputs (BYPASS) are available both at line level and through a headphone
amplifier capable of efficiently driving low impedance headphones. The headphone output volume is
adjustable in the analogue domain over a range of +6dB to –73dB and can be muted.
The design of the WM8711BL minimises power consumption without compromising performance. It
includes the ability to power off selective parts of the circuitry under software control, thus conserving
power. Separate power save modes can be configured under software control including a standby
and power off mode.
Special techniques allow the audio to be muted and the device safely placed into standby, sections of
the device powered off, volume levels adjusted without any audible clicks, pops or zipper noises.
Therefore standby and power off modes may be used dynamically under software control, whenever
playback is not required.
The device caters for a number of different sampling rates including industry standard 8kHz, 32kHz,
44.1kHz, 48kHz, 88.2kHz and 96kHz. The WM8711BL has two schemes to support the
programmable sample rates: Normal industry standard 256/384fs sampling mode may be used.
A
special USB mode is included, where all audio sampling rates can be generated from a 12.00MHz
USB clock. The digital filters used for playback are optimised for each sampling rate used.
The digital audio interface can support a range of audio data formats including I2S, DSP Mode (a
burst mode in which frame sync plus 2 data packed words are transmitted), MSB-First, left justified
and MSB-First, right justified. The digital audio interface can operate in both master or slave modes.
The software control uses either a 2 or 3-wire MPU interface.
PD, Rev 4.2, December 2011
1343
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
