WM8731 Datasheet, PDF (1/56 Pages) Wolfson Microelectronics plc – Portable Internet Audion CODEC with Headphone Driver and Programmable Sample Rates

WM8731
Portable Internet Audio CODEC with
Headphone Driver and Programmable Sample Rates
DESCRIPTION
The WM8731 is a low power stereo CODEC with an
integrated headphone driver. It offers the user the unique
ability to independently program the ADC and DAC sample
rates from a single clock source. The WM8731 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-
pin SSOP package.
BLOCK DIAGRAM
Advanced Information, Rev 2.0, February 2001
FEATURES
• Audio Performance
− 97dB SNR (‘A’ weighted @ 48kHz) ADC
− 100dB SNR (‘A’ weighted @ 48kHz) DAC
− 1.42 – 3.6V Digital Supply Operation
− 2.7 – 3.6V Analogue Supply Operation
• 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
• Stereo Audio Inputs and Outputs
• Microphone Input and Electret Bias with Side Tone Mixer
• Input and Output Volume and Mute Controls
• Highly Efficient Headphone Driver
• Playback Mode Power Consumption < 18mW
• Analogue Pass Through Power Consumption < 9mW
• 28-Pin SSOP Package
APPLICATIONS
• Portable MP3 Players and Recorders
• CD and Minidisc Recorders
AVDD
VMID
AGND
MICBIAS
RLINEIN
MICIN
VOL
+12 to -34.5dB,
1.5dB Steps
0dB/
20dB
LLINEIN
VOL
+12 to -34.5dB,
1.5dB Steps
MUTE
MUTE
MUX
MUTE
MUTE
MUX
ADC
ADC
OSC
CLKIN
DIVIDER
(Div x1, x2)
CLKOUT
DIVIDER
(Div x1, x2)
CONTROL INTERFACE
Bypass
MUTE
ATTEN/
MUTE
Side Tone
DAC
MUTE
Σ
DIGITAL
FILTERS
DAC
MUTE
Σ
DIGTAL AUDIO INTERFACE
Side Tone
ATTEN/
MUTE
MUTE
Bypass
WM8731
+6 to -73dB
1 dB Steps
VOL/
MUTE
H/P
DRIVER
HPVDD
HPGND
RHPOUT
ROUT
LOUT
VOL/
MUTE
+6 to -73dB
1 dB Steps
H/P
DRIVER
LHPOUT
WOLFSON MICROELECTRONICS LTD
Lutton Court, Bernard Terrace, Edinburgh, EH8 9NX, UK
Tel: [phone]
Fax: [phone]
Email: [e-mail]
www.wolfsonmicro.com
Advanced Information data sheets
contain preliminary data on new products
in the preproduction phase of
development. Supplementary data will be
published at a later date.
2001 Wolfson Microelectronics Ltd.