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Monolithic Linear IC
Monolithic Linear IC
Car Stereo 17 W Two-Channel BTL AF Amplifier
Car Stereo 17 W Two-Channel BTL AF Amplifier
LA4705NA
LA4705NA
Overview
The LA4705NA is a two-channel BTL power amplifier IC designed for car stereo systems. It was designed with
particular emphasis placed on achieving superb audio quality.
The low band frequency characteristics were extended with a new capacitor-free noise filter circuit, and
improvements in both circuit and pattern designs allow crosstalk, a source of audio quality problems, to be
reduced, resulting in audio with powerful bass and clear treble.
The LA4705NA also features a full complement of protection circuits and a standby mode switch.
Functions
Total output: 25 W + 25 W (V CC = 14.4 V, THD = 30%, R L = 4 )
Supports loads as low as R L = 2
Superb sound quality design (f L < 10 Hz, f H = 130 kHz)
Noise filter circuit does not require capacitors
The turn-on time can be set arbitrarily with an external capacitor
Extremely low levels of impulse noise
Built-in standby mode switching circuit (microcontroller support)
Built-in each protection circuit
Output pin-to-Vcc short
Output pin-to-GND short
Load short
Overvoltage
Thermal shutdown
Package: SIP18H
Block Diagram
100 F/16V
+
3
RIPPLE
FILTER
PREDRIVER
IN1
+
2
+
IN
2.2 F/
-
6.3V
PREDRIVER
PRE GND
4
BIAS
CIRCUIT
AMP
10K
OFF ON
STANDBY
5
SW
+5V
PREDRIVER
IN2
+
7
+
IN
2.2 F/
-
6.3V
PREDRIVER
POP NOISE
PREVENTION
CIRCUIT
6
8
+
+
33 F/
0.47 F/
1,9,10 Pin······Non connect
6.3V
6.3V
57 Car Audio
NC
+
V CC 1
1
18
2200 F
OUTPUT PIN TO V CC
SHORT PROTECTOR
INVERTING
OUT1
17
POWER
0.1 F
**
+
2.2
R L
LOAD SHORT
POWER
16
PROTECTOR
GND1
2 to 4
2.2
-
**
0.1 F
15
POWER
NON-INVERTING
OUT1
OUTPUT PIN-TO-GND
**
OVER VOLTAGE/
SHORT PROTECTOR
V CC
SURGE PROTECTOR
POLYESTER FILM
CAPACITOR
THERMAL
OUTPUT PIN-TO-GND
SHUTDOWN
SHORT PROTECTOR
NON-INVERTING
OUT2
14
POWER
0.1 F
**
+
2.2
LOAD SHORT
R L
POWER
13
PROTECTOR
2 to 4
GND2
2.2
-
**
0.1 F
12
POWER
INVERTING
OUTPUT PIN TO V CC
OUT2
SHORT PROTECTOR
9
10
11
V CC 2
NC
NC
Overview
The LA4708NF is two-channel BTL power amplifier IC designed for car stereo systems. It was designed with
particular emphasis placed on achieving superb audio quality.
The low band frequency characteristics were extended with a new capacitor-free noise filter circuit, and
improvements in both circuit and pattern designs allow crosstalk, a source of audio quality problems, to be
reduced, resulting in audio with powerful bass and clear treble.
The LA4708NF also features a full complement of protection circuits and a standby mode switch.
Note that the LA4708NF is pin compatible with the LA4705NA (car stereo 17 W two-channel power amplifier
IC), and allows end product power to be increased simply by switching ICs.
(Pins 1 and 9 must be left open to allow the same circuit board to be used.)
Functions
High power with a total output of 30 W + 30 W (V CC = 13.2 V, THD = 30%, R L = 4 )
Supports loads as low as R L = 2
Superb sound quality design (f L < 10 Hz, f H = 130 kHz)
Noise filter circuit does not require capacitors
The turn-on time can be set arbitrarily with an external capacitor
Extremely low levels of impulse noise
Built-in standby mode switching circuit (microcontroller support)
Built-in each protection circuit
Output pin-to-Vcc short
Output pin-to-GND short
Load short
Overvoltage
Thermal shutdown
Package: SIP18H
Block Diagram
V CC
PRE GND
AMP
OFF ON
10K
+5V
1,9 Pin······Don' t use
10 Pin······Non connect
Monolithic Linear IC
Monolithic Linear IC
Car Stereo 20 W Two-Channel BTL AF Amplifier
Car Stereo 20 W Two-Channel BTL AF Amplifier
LA4708NF
LA4708
(V CC = 13.2 V, THD = 30%, P O = 30 W)
100 F/16V
+
C2
3
1
OUTPUT PIN TO V CC
RIPPLE
SHORT PROTECTOR
FILTER
C1
PREDRIVER
POWER
IN1
+
2
+
LOAD SHORT
IN
PROTECTOR
2.2 F/
-
6.3V
PREDRIVER
POWER
4
BIAS
CIRCUIT
OVER VOLTAGE/
V CC
SURGE PROTECTOR
R1
THERMAL
STANDBY
5
SHUTDOWN
SW
C4
PREDRIVER
POWER
IN2
+
7
+
LOAD SHORT
IN
PROTECTOR
-
2.2 F/
6.3V
PREDRIVER
POWER
POP NOISE
OUTPUT PIN TO V CC
PREVENTION
CIRCUIT
SHORT PROTECTOR
6
8
9
10
+
+
N.C
33 F/
C3
0.47 F/
6.3V
6.3V
V CC
+
18
2200 F
C5
INVERTING
OUT1
17
0.1 F
**
C6
+
2.2
R L
POWER
R2
16
GND1
2 to 4
2.2
-
R3
**
0.1 F
C7
15
NON-INVERTING
OUT1
OUTPUT PIN-TO-GND
**
SHORT PROTECTOR
POLYESTER FILM
CAPACITOR
OUTPUT PIN-TO-GND
SHORT PROTECTOR
NON-INVERTING
OUT2
14
0.1 F
C8
**
+
2.2
R L
POWER
R4
13
2.2
2 to 4
GND2
-
R5
**
0.1 F
12
C9
INVERTING
OUT2
11
V CC 2
58 Car Audio
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