BA7781K Datasheet, PDF (1/7 Pages) Rohm – Stereo microphone amplifier for camcorders

Video ICs
Stereo microphone amplifier for cam-
corders
BA7781K
The BA7781K allows construction of a stereo-microphone amplifier for camcorder use with a minimum number of
external components. The IC has a built-in wind-noise detection circuit, and wind-noise rejection filter. The filter cir-
cuit is controlled automatically. The IC can operate off a 3.0V power supply.
•^Applications
Camcorders
•^Features
1) Operates off a 3.0V to 5.25V power supply.
2) Automatic wind-noise rejection circuit.
3) Matrix circuit for stereo emphasis.
4) Automatic switching circuit for external micro-
phones, built-in external monaural decision circuit,
and input switch mode decision circuit.
•^{Block diagram}
24 23 22 21 20 19 18 17
EXT IN L 25 _EXT
–
+
BG 26 ^INT 13dB
15dB
16 DET OUT
15 ^{DET IN}
INT IN L 27
GND 28
VREG 29
INT IN R ₃₀
+– _MIX
EXT
10dB
EXT
14 BIAS
BIAS
VCC
13 VCC
12 LPF INV OUT
+–
11 ^{LPF INV IN}
RIPL 31
INT
13dB
10 ^{MIX OUT}
+
EXT IN R 32 _EXT
–
15dB
09 MIC MONO
01 02 03 04 05 06 07 08
1