FROM EDN EUROPE: 24-bit DAC directly drives audio-power amplifiers
By Graham Prophet -- EDN, December 11, 2003
With Cirrus Logic's CS4351 digital-to-analogue converter, you can build an audio-signal chain that Cirrus says will save as much as 20% in bill-of-materials costs over previously available solutions. The company has used a high-voltage process to integrate a number of functions previously discretely implemented; the chip effectively eliminates analogue-signal-processing circuitry for a digital-audio design by providing direct line-out signal drives at a full 2V voltage swing. The integrated amplifier block includes a lowpass filter.
In the digital domain, the stereo DAC is a 24-bit-resolution part running at a 192-kHz sample rate. Dynamic range is quoted at 108 dB, and the corresponding THD+N figure is 95 dB. Outputs are single-ended, and the signal chain also incorporates the "Popguard" function to prevent any unwanted transients from reaching the audio output. The CS4351 will use 3.3V supplies for its digital circuitry and 9 or 12V for its analogue blocks (with separate supplies to reduced coupled noise). Cirrus will package the device in a 20-pin TSSOP.
Cirrus Logic, +44 1491 414030, www.cirrus.com.
