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DESCRIPTION
The WM8941 is a low power, high quality mono CODEC
designed for portable applications such as digital still cameras
or camcorders.
The device integrates support for a differential or single ended
mic, and includes drivers for speakers or headphone, and
mono line output. External component requirements are
reduced as no separate microphone or headphone amplifiers
are required. A high performance, low power current-mode
video buffer provides inherent short circuit protection.
An integrated video buffer is provided which has
programmable gain from 0-6dB (6-12dB unloaded), sync-tip
clamp and a 3
rd
order input low pass filter for signal re-
construction.
Advanced Sigma Delta Converters are used along with digital
decimation and interpolation filters to give high quality audio at
sample rates from 8 to 48ks/s. A selectable high pass filter
and four fully-programmable notch filters are available in the
ADC path. An advanced mixed signal ALC function with noise
gate is provided, while readback of PGA gain during ALC
operation is supported. The digital audio interface supports A-
law and
µ-law
companding.
An on-chip PLL is provided to generate the required Master
Clock from an external reference clock. The PLL clock can
also be output if required elsewhere in the system.
The WM8941 operates at supply voltages from 2.5 to 3.6V,
although the digital supplies can operate at voltages down to
1.71V to save power. Different sections of the chip can also be
powered down under software control using the selectable two
or three wire control interface.
WM8941 is supplied in a very small 4x4mm QFN package,
offering high levels of functionality in minimum board area,
with high thermal performance.
WM8941
Mono CODEC with Speaker Driver and Video Buffer
FEATURES
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Mono CODEC:
Audio sample rates:8, 11.025, 16, 22.05, 24, 32, 44.1, 48kHz
DAC SNR 98dB, THD -84dB (‘A’-weighted @ 8 – 48ks/s)
ADC SNR 94dB, THD -80dB (‘A’-weighted @ 8 – 48ks/s)
On-chip Headphone/Speaker Driver
- 40mW output power into 16Ω
- BTL speaker drive 0.4W into 8Ω
Additional MONO Line output
Multiple analog or ‘Aux’ inputs, plus analog bypass path
Mic Preamps :
Differential or single end Microphone Interface
- Programmable preamp gain
- Pseudo differential inputs with common mode rejection
- Programmable ALC / Noise Gate in ADC path
Low-noise bias supplied for electret microphones
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OTHER FEATURES
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Integrated video buffer with LPF and clamp.
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Digital Playback Limiter
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Programmable high pass filter (wind noise reduction)
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4 notch filters (narrowband noise suppression)
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On-chip PLL
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Low power, low voltage
- 2.5V to 3.6V (digital: 1.71V to 3.6V)
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4x4x0.75mm 28 lead QFN package
APPLICATIONS
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Digital still cameras and camcorders
General purpose mono audio CODEC with video buffer
WOLFSON MICROELECTRONICS plc
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Pre Production, Rev 3.3, December 2007
Copyright
©2007
Wolfson Microelectronics plc
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
