Audio ICs
Stereo pre-amplifiers with mute
detection circuits for car stereos
BA3430S / BA3430F / BA3430FS
The BA3430S, BA3430F, and BA3430FS are stereo pre-amplifiers with mute detection circuits which have been de-
signed for use in car stereos. The analog circuitry including the pre-amplifier and mute detection and the digital circuitry
such as control logic circuits have been combined together on a single chip. This has made it possible to reduce the
interface with the microcontroller to five parallel inputs and outputs, and enables a very compact circuit configuration
around the tape head.
The BA3430S, BA3430F, or BA3430FS makes it possible to easily incorporate an ultra-compact, high-precision pre-am-
plifier board into the mechanical components of a car stereo.
FAbsolute
maximum ratings (Ta = 25_C)
FRecommended
operating conditions (Ta = 25_C)
269
Audio ICs
FBlock
diagram
BA3430S / BA3430F / BA3430FS
270
Audio ICs
FPin
descriptions
BA3430S / BA3430F / BA3430FS
271
Audio ICs
BA3430S / BA3430F / BA3430FS
FElectrical
characteristics (unless otherwise noted, Ta = 25_C and V
CC
= 9V, f = 1kHz, R
g
= 680Ω, V
O
=
*10dBV)
272
Audio ICs
FMeasurement
circuit
BA3430S / BA3430F / BA3430FS
FAudio
signal amplification circuit
(1) Input switch circuit
This circuit switches between head A and head B as
needed for the auto reverse function.
A 10kΩ or less resistor must be connected to the input pin
to limit the input current.
Equivalent circuit schematic
The electrolytic capacitor between the input pin and
ground is for preventing switch noise. Although it is pos-
sible to prevent switch noise in the audio output without
this capacitor by using the mute circuit, switch noise in
the mute detection circuit will not be prevented and noise
will be recognized as a song.
Truth table
273