Copyright © Cirrus Logic, Inc. 2005
(All Rights Reserved)
http://www.cirrus.com
Multi-Bit A/D for Class-D Real-Time PSR Feedback
Features
z Advanced Multi-bit Delta-Sigma Architecture
z Real-time Feedback of Power Supply
Conditions (AC and DC)
z Filterless Digital Output Resulting in Very Low
Signal Delay
z 135 mW Power Consumption
z Supports Logic Levels Between 3.3 V and
5.0 V
z Differential Analog Architecture
z Modulator Overflow Detection
z Interfaces Directly to the CS44800/CS44600
Class-D PWM Modulator
z Multi-bit Conversion at up to 7.5 MHz
z 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
