CRD44600-PH-FB
Stereo 100 W PWM Amplifier Reference Design
Features
Two full-bridge channels, 100 W each
106 dB Dynamic Range - both channels
0.015% THD+N at 1 W
Power Supply Rejection (PSR) feedback
allowing amplifier to operate from low cost
linear unregulated power supplies
Spread Spectrum Modulation - Reduces
Modulation Energy
Passes CISPR and FCC requirements for
radiated and power line conducted
emissions
Independent peak signal limiting per channel
Thermal and over-current protection
> 85% amplifier efficiency
Works with GUI to configure the board
Demonstrates recommended layout and
grounding arrangements
controller. This reference design implements a two-
channel amplifier which delivers 100 W per full-bridge
channel into 8
Ω
loads using a single +50 V supply (at
1% THD+N). A 155 W unregulated linear power supply
is used to power the CRD44600-PH-FB.
As shown below, the CS44600 IC takes two stereo digi-
tal audio PCM inputs and converts them to PWM
outputs. This 64-pin LQFP PWM controller provides an
integrated sample rate converter for 32 kHz-192 kHz in-
put sample rate support, volume up/down, speaker load
compensation, peak limiting to prevent amplifier clipping,
power supply ripple compensation, and AM frequency
interference elimination.
This reference design uses the the Philips TDA8939, an
integrated power stage back end for digital amplifiers
(two TDA8939 parts configured as full-bridges are used
for this two-channel design). Current limiting and ther-
mal protection are provided by the TDA8939.
The inductor/capacitor 2
nd
order low pass filter (LPF) re-
moves high frequency components from the output
signal effectively converting it from digital to analog.
ORDERING INFORMATION
CRD44600-PH-FB
Reference Design
Description
The CRD44600-PH-FB PWM Amplifier demonstrates
the CS44600, Cirrus’ multi-channel pure digital PWM
I
+50 V
PSR Circuitry
155W Unregulated
Linear Power Supply
+50 V
CS4461 ADC
+50 V
Channel 1
PCM Clocks & Data
Philips
TDA8939
LPF
8
Ω
Audio Inputs and GUI
Interface
I
2
C Host Control
CS44600
(PWM Controller)
Channel 2
+50 V
Philips
TDA8939
LPF
8
Ω
Cirrus Logic, Inc.
www.cirrus.com
Copyright
©
Cirrus Logic, Inc. 2005
(All Rights Reserved)
MAR '05
DS633RD1
1
CIRRUS [ CIRRUS LOGIC ]
