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DESCRIPTION
The WM8976 is a low power, high quality codec designed for
portable applications such as Digital still camera or Digital
Camcorder.
The device integrates a preamp for a differential mic, and
includes drivers for speakers, headphone and differential or
stereo line output. External component requirements are
reduced as no separate microphone or headphone amplifiers
are required.
Advanced on-chip digital signal processing includes a 5-band
equaliser, a mixed signal Automatic Level Control for the
microphone or line input through the ADC as well as a purely
digital limiter function for record or playback. Additional digital
filtering options are available in the ADC path, to cater for
application filtering such as ‘wind noise reduction’.
The WM8976 CODEC can operate as a master or a slave. An
internal PLL can generate all required audio clocks for the
Codec from common reference clock frequencies, such as
12MHz and 13MHz.
The WM8976 operates at analogue supply voltages from 2.5V
to 3.6V, although the digital core can operate at voltages down
to 1.8V to save power. The speaker outputs and OUT3/4 line
outputs can run from a 5V supply if increased output power is
required. Individual sections of the chip can also be powered
down under software control.
WM8976
Low Power CODEC With Speaker Driver
FEATURES
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Stereo Codec:
DAC SNR 98dB, THD -84dB (‘A’ weighted @ 48kHz)
ADC SNR 90dB, THD -80dB (‘A’ weighted @ 48kHz)
On-chip Headphone Driver with ‘capless’ option
- 40mW output power into 16Ω / 3.3V SPKVDD
0.9W output power into 8Ω BTL speaker / 5V SPKVDD
- Capable of driving piezo speakers
- Stereo speaker drive configuration
Mic Preamps:
Differential or single-ended microphone Interface
- Programmable preamp gain
- Psuedo differential input with common mode rejection
- Programmable ALC / Noise Gate in ADC path
Low-noise bias supplied for electret microphones
Other features:
Enhanced 3-D function for improved stereo separation
Digital playback limiter
5-band Equaliser (record or playback)
Programmable ADC High Pass Filter (wind noise reduction)
Programmable ADC Notch Filter
Aux inputs for stereo analog input signals or ‘beep’
On-chip PLL supporting 12, 13, 19.2MHz and other clocks
Low power, low voltage
- 2.5V to 3.6V (digital core: 1.8V to 3.6V)
- power consumption <30mW all-on with 2.5V supplies
5x5mm 32-pin QFN package
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APPLICATIONS
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Stereo Camcorder or DSC
WOLFSON MICROELECTRONICS plc
www.wolfsonmicro.com
Preliminary Technical Data, February 2005, Rev 2.0
Copyright
2005
Wolfson Microelectronics plc
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
