LXE1710 E
VALUATION
B
OARD
U
SER
G
UIDE
Part Number
LX1710CDB
LX1711CDB
LXE1710
Product
AudioMAX High
Fidelity Controller IC
AudioMAX High
Power Controller IC
LX1710 AudioMAX
Evaluation Board
Description
V
DD
= 7V to 15V, Switching Class-D Mono
Power Amplifier IC, 28-Pin SSOP Package.
V
DD
= 7V to 25V, Switching Class-D Mono
Power Amplifier IC, 28-Pin SSOP Package.
Fully Operational Mono Audio Amplifier.
LX1710/1711 A
UDIO
MAX E
VALUATION
B
OARD
F
EATURES AND
C
IRCUIT
D
ESCRIPTION
•
•
•
•
Fully Assembled Mono Evaluation Board with
LX1710 Class-D Controller IC
Improved SNR and Noise Floor Performance
Output Power of 25W typical (LX1710, 15V
DD
,
•
•
•
•
Supports Full Audio Bandwidth
Terminal Block Connectors for
Voltage and Speaker Connection
RCA Plug for Audio Input Signal
Supply
Output Power of 54W typical (LX1711, 25V
DD
,
The AudioMAX Evaluation Amplifier Board allows the
user to quickly connect and evaluate the LX1710
Switching Class-D Mono Controller IC. Easy-to-
connect terminal blocks and an RCA plug are
provided for interfacing to Power, Speaker, and Audio
Input connections. The single stage output filter has
been configured to drive a 4
audio bandwidth amplification (See Application
section LC filter design for component selection,
calculations, and suggested inductor and capacitor
values for other loads). The LXE1710 Evaluation
Board operates from a single supply voltage.
The Class-D Amplifier Controller IC requires a
minimal number of external components to create a
complete amplifier solution. See LXE1710 Evaluation
Board Schematic and Bill of Materials for circuit
specifics.
A Class-D Amplifier is a “switching”
amplifier that converts a low-level, analog audio input
signal into a high power, pulse-width modulated
(PWM) output. The switching frequency (500kHz
typical but can be adjusted) is much higher than the
audio bandwidth (20Hz to 20kHz), and is easily
filtered out with a simple LC filter. The support
circuitry can be generally grouped into three areas
(input circuit, output power stage, and output filter).
I
NPUT
C
OMPENSATION
The first group is the compensation network and
control setting components. These resistors and
capacitors set up the controller operating frequency,
response characteristics, and comparator ramp
fundamental to Class-D operation.
O
UTPUT
S
TAGE
The next section is the output stage. The controller
IC generates a PWM output by controlling external
FETs connected in a full bridge configuration. The full
bridge configuration is connected between the single
supply voltage (PVDD) and ground (PGND) with the
output of the bridge driving the LC filter stage.
Because the FETs are either fully “on” or fully “off”,
Class-D topology is extremely efficient (up to 85%
typical), circuit power dissipation is minimal, and
maximum power is delivered to the speaker. The
bridge output also drives the RC low pass filter, which
provides the feedback for the control loop through the
FBK+ and FBK- inputs.
F
ILTER
S
TAGE
The single stage, second order LC filter is used to
remove the switching frequency. The frequency
response and corner frequency can be easily
adjusted for optimization of various loads. The LC
evaluation board component values have been
chosen for a 4
! " # $
for component selection.
Copyright
©
2000
Rev. 1.1, 2000-12-01
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 4
MICROSEMI [ MICROSEMI CORPORATION ]
