251
Audio ICs
Double cassette tape recorder system
preamplifier
BA3423S
The BA3423S is a record/playback system preamplifier for radio cassette decks. With four control pins it allows switch-
ing between I/O for the A (play only) and B (record and play) mechanisms, input for tape, radio, and microphone, on
and off switching for line out and recording output, and equalizer switching for normal and high-speed dubbing.
It requires about half the number of external components of its predecessors which means simplified assembly and over-
all cost savings.
Applications
Dual-cassette radio cassette players.
Features
1) Built-in switch for playback equalizer amplifier for the
A and B mechanisms.
2) Built-in normal/high-speed equalizer switch for the
playback equalizer amplifier.
3) The B mechanism input is also used as the recording
output, so a switch is not required.
4) Built-in tape/radio input switch, and microphone mix-
ing.
5) The microphone amplifier is used as the mixing am-
plifier, and the line can be muted to allow the built-in
microphone to be used for recording.
6) Built-in ALC circuit.
7) Built-in recording equalizer circuit, and internal
switching of the normal/high-speed equalizer is
possible.
8) All stages are directly connected, so coupling ca-
pacitors are not required.
9) Muting is applied as required during switching to re-
duce switching noise (transition muting).
10) Pin assignments has been designed to facilitate
placement of attached components and PCB de-
sign.
Absolute maximum ratings (Ta = 25 C)
Recommended operating conditions (Ta = 25 C)