Xilinx XAPP169 Crystal CS4343 Stereo DAC

6www.xilinx.com XAPP169 (v1.0) November 24, 1999

1-800-255-7778

MP3 NG: A Next Generation Consumer Platform R

Crystal CS4343

Stereo DAC The Digital-to-Analog Converter chosen for this design is the Crystal CS4343 from Cirrus

Logic. This device features:

•1.8V to 3.3V operation.

•24-bit conversion at up to 96 kHz.

•Digital volume control.

•Digital bass and treble boost.

•Built-in headphone amplifier capable of delivering 5 mW into a 16 Ω loa d.

Figure 5 shows the block diagram for this device.

The CS4343 provides three interfaces: the analog stereo headphone interfac e, the serial port

used to transfer digital audio data streams, and the control port used to conf igure the device.

The control port is an industry standard I2C slave interface. I2C is a mul tidrop, 2-wire, serial

interface consisting of a clock (SCL) and data (SDA) and operating at up to 100 kHz . (See

Figure 7 Control Port Timing.) The control port is used to configure device features such as

volume, muting, equalization, power management, and the operating mode of t he serial port.

Figure 1 on page 3 gives an overview of control port timing. A detailed description of I2C

operation can be found in the I2C specification as described in the references.

LK/DEM

SDATA

DIF1/SDA

MCLK

VA_HP

SERIAL

PORT

DE-

CONTROL PORT

∆Σ

DAC

RST

LRCK

DIF0/SCL

VD_IO

DIGITAL

VOLUME

CONTROL

BASS/TREBLE

BOOST

COMPRESSION

LIMITING ∆Σ

DAC

DIGITAL

FILTERS

ANALOG

FILTER

ANALOG

FILTER

GND FILT+ REF_GND

ANALOG

VOLUME

CONTROL

HEAD-

PHONE

AMPLIFIER

ANALOG

VOLUME

CONTROL

EMPHASIS

VQ_HP

Figure 5: CS4343 Block Diagram

(Courtesy Cirrus Logic)