LX1725ILQ Microsemi Analog Mixed Signal Group, LX1725ILQ Datasheet - Page 10

• Manufacturer Part Number: LX1725ILQ
• Description: IC AMP AUDIO 32W STER D 32MLPQ
• Manufacturer: Microsemi Analog Mixed Signal Group
• Series: AudioMAX™r
• Type: Class Dr

Specifications of LX1725ILQ

• Output Type: 1-Channel (Mono) or 2-Channel (Stereo)
• Max Output Power X Channels @ Load: 32W x 1 @ 8 Ohm; 16W x 2 @ 4 Ohm
• Voltage - Supply: 12 V ~ 35 V, ±6 V ~ 17.5 V
• Features: Depop, Differential Inputs, Mute, PWM, Short-Circuit and Thermal Protection, Standby
• Mounting Type: Surface Mount
• Package / Case: 32-MLPQ
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Copyright © 2004
Rev. 1.2, 2005-12-06
S
Forcing the STBY pin high puts the LX1725 into a zero current
sleep mode. The outputs enter a high impedance mode and all
internal bias circuits are disabled.
O
The LX1725 has built-in over circuit protection. The circuit works
by monitoring the voltage drop across whichever power FET is
active. When this voltage is greater than a certain threshold, an
over-current condition is assumed. If this condition occurs during
five consecutive clock cycles, then the output transistors are
immediately disabled. The hiccup counter then counts 65536 clock
cycles before allowing the outputs to begin switching again.
During this period the FLAG pin goes to HIGH to indicate a
system fault. A “hiccup” condition will be clearly audible if a
speaker is connected to the outputs. The threshold for the over-
current condition is set to 3.75A.
The over current circuit hiccup protection can be disabled by
pulling the RILIM pin to V5V.
U
If the voltage drops below ±5V under dual supply operation or 10V
under single supply operation, the under voltage lock out circuit is
activated and the LX1725 will enter the standby mode. This
switch-off will be silent and without pop noise. It will be recovered
when the supply voltage rises above the threshold level.
The FLAG pin will go logic HIGH to indicate the system fault. A
similar circuit monitors V5V with a threshold of 4V.
TAND BY
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URRENT
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11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: [phone]
UT
(UVLO)
F U N C T I O N D E S C R I P T I O N ( C O N T I N U E D )
Integrated Products Division
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Microsemi
T
When the junction temperature exceeds 125°C, the gain is reduced
by 6dB (gain fold back) to reduce the output power and on-chip
power dissipation., when the temperature drops below 110°C the
gain will returns to normal. When the temperature exceeds 155°C
the outputs are shut off to force the output current to zero. Again,
when the temperature drops below 130°C the outputs are allowed
to switch and normal operation resumes.
A
For a high common mode rejection ratio and a maximum
flexibility in the application, the audio inputs are fully differential.
By connecting the inputs anti-parallel the phase of one of the
channels can be inverted, so that a load can be connected between
the two output filters. In this case the system operates as a mono
BTL amplifier and with the same loudspeaker impedance an
approximately four times higher output power can be obtained.
The input configuration for a mono BTL application is illustrated
in Figure 6. In the stereo single-ended configuration it is also
recommended to connect the two differential inputs in anti-phase.
This has advantages for the current handling of the power supply at
low signal frequencies.
HERMAL
UDIO
I
NPUT
15W+15W Stereo Class-D Amplifier
P
Figure 6 – Audio Input Block Diagram
ROTECTION
IN1+
IN2+
IN1-
IN2-
Filterless 30W Mono in BTL
P
RODUCTION
Vref
Vref
D
LX1725
ATA
S
HEET
OUT1
OUT2
LX1725
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