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Stereo CODEC with Speaker Driver
DESCRIPTION
The WM8976 is a low power, high quality CODEC designed
for portable applications such as multimedia phone, digital
still camera or digital camcorder.
The device integrates a preamp for differential microphone,
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 digital audio interface 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 3.3V, although the digital core can operate at
voltages down to 1.71V 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
FEATURES
Stereo CODEC:
DAC SNR 98dB, THD -84dB (‘A’ weighted @ 48kHz)
ADC SNR 95dB, THD -84dB (‘A’ weighted @ 48kHz)
On-chip Headphone Driver with ‘capless’ option
- 40mW per channel into 16 / 3.3V SPKVDD
1W output power into 8 BTL speaker / 5V SPKVDD
- Capable of driving piezo speakers
- Stereo speaker drive configuration
Mic Preamps:
Differential or single-ended microphone interfaces
- Programmable preamp gain
- Pseudo differential input with common mode rejection
- Programmable ALC / Noise Gate in ADC path
Low-noise bias supplied for electret microphone
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 analogue input signals or ‘beep’
On-chip PLL supporting 12, 13, 19.2MHz and other clocks
Support for 8, 11.025, 12, 16, 22.05, 24, 32, 44.1 and 48kHz
sample rates
Low power, low voltage
- 2.5V to 3.6V (digital: 1.71V to 3.6V)
5x5mm 32-lead QFN package
APPLICATIONS
Stereo Camcorder or DSC
Multimedia Phone
WOLFSON MICROELECTRONICS plc
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Production Data, November 2011, Rev 4.5
Copyright
2011
Wolfson Microelectronics plc
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
