WM8721 Datasheet, PDF (1/34 Pages) Wolfson Microelectronics plc – Internet Audio DAC with Integrated Headphone Driver

WM8721
Internet Audio DAC with Integrated Headphone Driver
Product Preview, November 2000, Rev 1.3
DESCRIPTION
The WM8721 is a low power stereo DAC with an integrated
headphone driver. The WM8721 is designed specifically for
portable MP3 audio and speech players. The WM8721 is
also ideal for MD, CD machines and DAT players.
Stereo 24-bit multi-bit sigma delta DACs are used with
oversampling digital interpolation 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 20-
pin SSOP package.
A USB mode is provided where all audio rates can be
derived from a simple 12MHz MCLK, saving on need for
PLL or multiple crystals.
FEATURES
• Audio Performance
− 100dB SNR (‘A’ weighted @ 48kHz) DAC
− 1.42 – 3.6V Digital Supply Operation
− 2.7 – 3.6V Analogue Supply Operation
• DAC Sampling Frequency: 8KHz – 96KHz
• 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
• Stereo Audio Outputs
• Output Volume and Mute Controls
• Highly Efficient Headphone Driver
• Playback Mode Power Consumption < 18mW
• 20-Pin SSOP Package
APPLICATIONS
• Portable MP3 Players
• CD and Minidisc Players
BLOCK DIAGRAM
DACDAT (3)
DACLRC (4)
BCLK (2)
(15) (16) (17) (14)
(11) (13) (12)
WM8721
CONTROL INTERFACE
DIGITAL
FILTERS
DAC
+6 to -73dB
1 dB Steps
VOL/
MUTE
H/P
DRIVER
CLKIN
DIVIDER
(Div x1, x2)
(18)
DAC
(19) (1) (20)
VOL/
MUTE
H/P
DRIVER
+6 to -73dB
1 dB Steps
(5) HPVDD
(8) _HPGND
(7) RHPOUT
(10) ROUT
(9) LOUT
(6) _LHPOUT
WOLFSON MICROELECTRONICS LTD
Lutton Court, Bernard Terrace, Edinburgh, EH8 9NX, UK
Tel: [phone]
Fax: [phone]
Email: [e-mail]
http://www.wolfson.co.uk
Product Preview data sheets contain
specifications for products in the formative
phase of development. These products may
be changed or discontinued without notice.
2000 Wolfson Microelectronics Ltd.