WM8974_07 Datasheet, PDF (1/87 Pages) Wolfson Microelectronics plc – Mono CODEC with Speaker Driver

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WM8974
Mono CODEC with Speaker Driver
DESCRIPTION
The WM8974 is a low power, high quality mono CODEC
designed for portable applications such as Digital Still Camera
or Digital Voice Recorder.
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.
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. Additional digital filtering
options are available in the ADC path, to cater for application
filtering such as ‘wind noise reduction’, plus an advanced
mixed signal ALC function with noise gate is provided. 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 WM8974 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. The speaker and mono outputs use a
separate supply of up to 5V which enables increased output
power if required. Different sections of the chip can also be
powered down under software control by way of the selectable
two or three wire control interface.
WM8974 is supplied in a very small 4x4mm QFN package,
offering high levels of functionality in minimum board area,
with high thermal performance.
FEATURES
• 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 -83dB (‘A’-weighted @ 8 – 48ks/s)
• On-chip Headphone/Speaker Driver with ‘cap-less’ connect
- 40mW output power into 16Ω / 3.3V SPKVDD
- BTL speaker drive 0.9W into 8Ω / 5V SPKVDD
• Additional MONO Line output
• Multiple analog or ‘Aux’ inputs, plus analog bypass path
• Mic Preamps:
• Differential or single end Microphone Interface
- Programmable preamp gain
- Psuedo differential inputs with common mode rejection
- Programmable ALC / Noise Gate in ADC path
• Low-noise bias supplied for electret microphones
OTHER FEATURES
• 5 band EQ (record or playback path)
• Digital Playback Limiter
• Programmable ADC High Pass Filter (wind noise reduction)
• Programmable ADC Notch Filter
• On-chip PLL
• Low power, low voltage
- 2.5V to 3.6V (digital: 1.71V to 3.6V)
- power consumption <10mA all-on 48ks/s mode
• 4x4x0.9mm 24 lead QFN package
APPLICATIONS
• Digital Still Camera Audio Codec
• Wireless VoIP and other communication device handsets /
headsets
• Portable audio recorder
• General Purpose low power audio CODEC
WOLFSON MICROELECTRONICS plc
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Production Data, Rev 4.2 March 2007
Copyright ©2007 Wolfson Microelectronics plc