BA7746 Просмотр технического описания (PDF) - ROHM Semiconductor

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производитель

BA7746

VCR Hi-Fi audio signal REC / PB amplifier

ROHM Semiconductor 

Video ICs

•Pin descriptions

Pin No.

Pin name, function and remarks

〈VCC REC + B〉

1

• Power supply for REC + B.

• Connect to VCC (pin 7).

Voltage

VCC

BA7746S / BA7746FS

Circuit diagram

—

〈REC TC〉

• REC + B time constant.

2

• Use to adjust the REC + B rise time using the C

value. The value of the built-in resistor is 20kΩ.

• The effect of current spikes when recording is

started is reduced

REC: 0.9V

PB: 0V

REC

20k

〈HSWP IN〉

3

• Pulse input for head switching.

• ch1: H, ch2: L

—

24k

〈EP / SP CTRL〉

• EP / SP mode control.

4

• In EP mode, the playback amplifier gain is set to

—

+ 5dB (Typ.).

• EP: H, SP: L

• Do not leave open circuit

〈PRE OUT〉

• Playback amplifier output.

• Open emitter output.

REC: 3.6V

5

• When there is a chance of oscillation due to

capacitive load, reduce the output current, or

PB: 1.9V

(RL: 1.8kΩ)

connect a resistor in series (approx. 390Ω).

• Avoid capacitive coupling with the playback input

〈VCA CTRL (PRE MUTE)〉

• VCA control.

6

• When the terminal is open (a C is required), the

playback amplifier gain is set to the Typ. value.

REC: 2.0V

PB: 2.0V

• The PRE MUTE function is made possible by

connection of a mute H signal to this

through a diode

40k

EP SP

30k

580

20k

MUTE H

3

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