Copyright

© Cirrus Logic, Inc. 2005

(All Rights Reserved)

http://www.cirrus.com

Multi-Bit A/D for Class-D Real-Time PSR Feedback

Features

Advanced Multi-bit Delta-Sigma Architecture

Real-time Feedback of Power Supply

Conditions (AC and DC)

Filterless Digital Output Resulting in Very Low

Signal Delay

135 mW Power Consumption

Supports Logic Levels Between 3.3 V and

5.0 V

Differential Analog Architecture

Modulator Overflow Detection

Interfaces Directly to the CS44800/CS44600

Class-D PWM Modulator

Multi-bit Conversion at up to 7.5 MHz

Delivers Modulated Data Over 2-Wire Interface

General Description

The CS4461 is a complete analog-to-digital converter

for class-D real-time power supply rejection (PSR) feed-

back. It performs sampling and analog-to-digital

conversion, generating digital data for input to a

class-D modulator with real-time PSR feedback

capabilities.

The CS4461 uses a 5th-order, multi-bit delta-sigma

modulator followed by output data formatting. The ADC

uses a differential architecture which provides excellent

noise rejection.

The CS4461 feeds back the AC and DC voltage compo-

nents and is ideal for class-D audio systems requiring

high power supply rejection.

The CS4461 is available in a 24-pin TSSOP package in

both Commercial (-10° to +70° C) and Automotive

grade (-40° to +85° C). The CDB44800 Customer Dem-

onstration board is also available for device evaluation

and implementation suggestions. Please see “Ordering

Information” on page 11 for complete details.

Voltage Reference

REFGND

AIN-

AIN+

FILT+

PSR_DATA

PSR_SYNC

5.0 V

(VA)

GND

VQ

PSR_MCLK

S/H

+

-

LP Filter

∆Σ

DAC

Output Data

Formatting

3.3 V to 5.0 V

(VDP)

PSR_EN

OVERFLOW

PSR_RESET

SEPTEMBER '05

DS650F1

CS4461