1

Video ICs

VCR Hi-Fi audio signal REC / PB

amplifier

BA7746S / BA7746FS

The BA7746S and BA7746FS contains the recording and playback amplifiers required for Hi-Fi VCR signal process-

ing. The recording system uses a constant-current amplifier with AGC to eliminate the need to adjust the recording

current, and ensure stable operation as the head wears. The IC also features REC MUTE and OVER REC functions.

The playback system has a high-gain preamplifier, a low- offset head switch, VCA, and an EP-gain amplifier.

In addition, all functions operate off a single 5V supply, and a H / L control system eliminates the need for special

power supplies for the recording and playback systems. The IC has low power consumpution, and comes in a com-

pact 32-pin SSOP-A package that requires little area on the PCB. It will improve the reliability and performance of

your designs while reducing external component requirements.

VCRs

1) The low-noise playback amplifier has a total gain of

79dB (Typ.). Designed for VHS-band operation with

low external parts count. It has two built-in circuits

for Hi-Fi VCR operation.

2) The circuit has been designed to suppress head-

switching noise.

3) Built-in EP / SP gain switching function that boosts

the playback gain by 5dB.

4) Built-in VCA for easy playback output adjustment.

5) High-output recording amplifier for audio FM record-

ing.

6) Constant-current drive povides stable recording

characteristics when the load (head impedance) is

fluctuating.

7) Built-in recording level AGC eliminates the need to

adjust recording current.

8) Built-in low-pass filter limits the input bandwidth of

the recording amplifier.

9) Built-in OVER REC recording current amplifier

function and REC MUTE function that stops record-

ing output.

10) Low power consumption. Operates off a single 5V

power supply.

11) Record / playback switching can be done directly

via the system controller, and consumes littele

power.

12) Possible to construct a high-performance audio

system by pairing this chip with a Hi-Fi-audio signal

processing IC.

Parameter

Symbol

Limits

Unit

7.0

V

BA7746S

BA7746FS

Pd

mW

mW

Topr

– 10 ~ + 70

°C

Tstg

– 55 ~ + 125

°C

Power supply voltage

Power

dissipation

Operating temperature

Storage temperature