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5 to 7.1 Channel PWM Controller
DESCRIPTION
The WM8608 comprises a high performance multi-channel
PWM digital power amplifier controller. Simply by adding
appropriate power output stages a multi-channel power
amplifier may be built. Six identical full audio bandwidth
channels, plus a reduced bandwidth sub channel are
provided as PWM outputs, to drive 6 speakers plus Sub.
The PCM to PWM converter supports up to 7.1 channels of
audio, in PCM input formats. These may be mixed down to
6.1 or 5.1 outputs, by mixing rear channel data into centre
rear or surround speakers if required. If 5.1 channel data is
input, the surround data may be processed internally to
create a pseudo 6.1 signal with rear channel output.
A Graphic Equaliser function is provided, plus selectable
high frequency equalisation to suit different speaker types.
Independent volume control for each channel is provided.
The WM8608 PWM controller is compatible with integrated
switching output stages available from a number of vendors
or alternatively may be used with a discrete output stage
configuration and achieve similar levels of performance.
A Dynamic Peak Compressor with programmable attack
and decay times is included, which allows headroom for
tone control, bass management and extra digital gain to be
provided, without clipping occurring.
A Synchroniser allows slaving to LRCLK, thus making the
WM8608 independent of source MCLK frequency and jitter.
The device is controlled via a 2/3 wire serial interface. The
interface provides access to all features including channel
selection, volume controls, mutes, de-emphasis and power
management facilities. The device is supplied in a 48-pin
TQFP package.
WM8608
FEATURES
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Multi-channel PWM audio amplifier controller
Supports Stereo, 5.1, 6.1 or 7.1 inputs
Supports 2.1, 5.1 or 6.1 outputs with optional rear centre
channel generation
PWM Audio Performance with typical output stage
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100dB SNR (‘A’ weighted @ 48kHz)
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0.01% THD @ 1Watt
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0.1% THD @ 30Watt
Integrated Bass Management support with adjustable filter
Integrated 4-band Graphic Equaliser for 3 front channels
Adjustable output stage filter compensation for different
speakers
Volume control on each 6.1 channel +24dB to -103.5dB in
0.5dB steps, with volume ramping and auto-mute
functions
Programmable Dynamic Peak Compressor avoids clipping
even at high volume settings
Internal PLL and optional crystal oscillator, supporting
Audio and MPEG standards
2/3-Wire MPU Serial Control Interface
Master or Slave Clocking Mode
Programmable Audio Data Interface Modes
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I
2
S, Left, Right Justified or DSP
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16/20/24/32 bit Word Lengths
De-emphasis support for stereo
Selectable CMOS or LVDS digital outputs
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APPLICATIONS
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Surround Sound AV Processors and Hi-Fi systems
Automotive Audio
DVD receivers
WOLFSON MICROELECTRONICS plc
www.wolfsonmicro.com
Product Preview, March 2004, Rev 1.5
Copyright
2004
Wolfson Microelectronics plc
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
