WM8731_09 Datasheet, PDF (1/64 Pages) Wolfson Microelectronics plc – Portable Internet Audio CODEC with Headphone Driver and Programmable Sample Rates

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WM8731 / WM8731L
Portable Internet Audio CODEC with Headphone Driver
and Programmable Sample Rates
DESCRIPTION
The WM8731 or WM8731L (WM8731/L) are low power
stereo CODECs with an integrated headphone driver. The
WM8731/L is designed specifically for portable MP3 audio
and speech players and recorders. The WM8731 is also
ideal for MD, CD-RW machines and DAT recorders.
Stereo line and mono microphone level audio inputs are
provided, along with a mute function, programmable line
level volume control and a bias voltage output suitable for
an electret type microphone.
Stereo 24-bit multi-bit sigma delta ADCs and DACs are
used with oversampling digital interpolation and decimation
filters. Digital audio input word lengths from 16-32 bits and
sampling rates from 8kHz to 96kHz are supported.
Stereo audio outputs are buffered for driving headphones
from a programmable volume control, line level outputs are
also provided along with anti-thump mute and power
up/down circuitry.
The device is controlled via a 2 or 3 wire serial interface.
The interface provides access to all features including
volume controls, mutes, de-emphasis and extensive power
management facilities. The device is available in a small 28-
lead SSOP package or the smaller 28 lead quad flat
leadless package (QFN).
BLOCK DIAGRAM
FEATURES
• Highly Efficient Headphone Driver
• Audio Performance
- ADC SNR 90dB (‘A’ weighted) at 3.3V, 85dB at 1.8V
- DAC SNR 100dB (‘A’ weighted) at 3.3V, 95dB at 1.8V
• Low Power
- Playback only 22mW, 8mW (‘L’ Variant)
- Analogue Pass Through 12mW, 3.5mW (‘L’ variant)
- 1.42 – 3.6V Digital Supply Operation
- 2.7 – 3.6V Analogue Supply Operation
- 1.8 – 3.6V Analogue Supply Operation (‘L’ Variant)
• ADC and DAC Sampling Frequency: 8kHz – 96kHz
• Selectable ADC High Pass Filter
• 2 or 3-Wire MPU Serial Control Interface
• Programmable Audio Data Interface Modes
- I²S, Left, Right Justified or DSP
- 16/20/24/32 bit Word Lengths
- Master or Slave Clocking Mode
• Microphone Input and Electret Bias with Side Tone Mixer
• Available in 28-lead SSOP or 28-lead QFN package
APPLICATIONS
• Portable MP3 Players and Recorders
• CD and Minidisc Recorders
• PDAs / smartphones
WOLFSON MICROELECTRONICS plc
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Production Data, April 2009, Rev 4.8
Copyright ©2009 Wolfson Microelectronics plc