WM8950 Datasheet, PDF (1/52 Pages) Wolfson Microelectronics plc – ADC WITH MICROPHONE INPUT AND PROGRAMMABLE DIGITAL FILTERS

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WM8950
ADC with Microphone Input and Programmable Digital Filters
DESCRIPTION
The WM8950 is a low power, high quality mono ADC designed
for portable applications such as Digital Still Camera, Digital
Voice Recorder or games console accessories.
The device integrates support for a differential or single ended
mic. External component requirements are reduced as no
separate microphone amplifiers are required.
Advanced Sigma Delta Converters are used along with digital
decimation filters to give high quality audio at sample rates
from 8 to 48ks/s. Additional digital filtering options are
available, to cater for application filtering such as wind noise
reduction, noise rejection, plus an advanced mixed signal ALC
function with noise gate is provided.
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 WM8950 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 by way of the selectable
two or three wire control interface.
WM8950 is supplied in a very small 4x4mm QFN package,
offering high levels of functionality in minimum board area,
with high thermal performance.
FEATURES
• Mono ADC:
• Audio sample rates:8, 11.025, 16, 22.05, 24, 32, 44.1, 48kHz
• SNR 95dB, THD -85dB (‘A’-weighted @ 8 – 48ks/s)
• Multiple auxiliary analog inputs
• 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
• Programmable High Pass Filter (wind noise reduction)
• Fully Programmable IIR Filter (notch filter)
• On-chip PLL
• Low power, low voltage
- 2.5V to 3.6V (digital: 1.71V to 3.6V)
- power consumption TBD all-on 48ks/s mode
• 4x4x0.9mm 24 pin QFN package
APPLICATIONS
• Digital Still Camera
• General Purpose low power audio ADC
• Games console accessories
• Voice recorders
WOLFSON MICROELECTRONICS plc
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Preliminary Technical Data, June 2005, Rev 2.1
Copyright 2005 Wolfson Microelectronics plc