WM8721: Stereo DAC with headphone driver
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 or 24MHz master clock, eliminating the need for a PLL or multiple crystals.
- Audio Performance
- DAC SNR 100dB (‘A’ weighted) at AVDD = 3.3V
- 1.42 – 3.6V Digital Supply Operation
- 2.7 – 3.6V Analogue Supply Operation
- Low Power
- Headphone Playback: 20mW at AVDD = 3.3V
- 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
- 20-Pin SSOP Package