BA7795FS View Datasheet(PDF) - ROHM Semiconductor

Part Name

Description

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BA7795FS

VCR standard audio signal processor

ROHM Semiconductor 

Video ICs

•Circuit operation

(1) EE oparation

The input switch is used to select the audio signal input

source (LINE or TUER). This signal is amplified by the

line amplifier (voltage gain: 20dB at 1kHz).

The ALC circuit controls the line amplifier output level.

The ALC level is set externally.

If mute mode is set in this state, the switch that con-

nects the output buffer will go off, but the ALC loop will

not be cut.

Signal flow for EE and recording operation

BA7795LS / BA7795FS

(2) Recoeding

In recording mode, the recording amplifier directly con-

nected to the line amplifier operates.

The PB HEAD switch in the playback equalizer amplifi-

er block switches on, and the signal is not input to the

playback equalizer amplifier.

The line amplifier output is attenuated by 20dB before it

is input to the recording amplifier, so if the feedback

components are chosen to given a gain of 20dB, the

same REC OUT output level as the line amplifier can

be obtained.

It is also possible to switch the REC equalizer charac-

teristic to suit the tape speed by switchig the control

signal to EQ CTRL. The recording amplifier gain and

equalizer characteristics are set externally.

1

3

22µ

5

33µ

VCC

7

EQ CTRL

9

PB / TU / EE

CTRL

11

39k

13

8.2k

15

MUTE

CTRL

17

1.5k

19

15k

21

23

BIAS

OSC

REC + B

3.3µ

2

22µ 330

4

ALC

LINE

+ 28dB

6

8

8.2k

10

330k

12k

4.7k

0.01µ

4.7k

0.1µ

12

47µ

14

2.2M

16

LINE IN

18

TUNER IN

REC

20

RL

22

LINE OUT

– 20dB

10µ

REC / EE

EP

24

CTRL

BA7795LS

Units: R [Ω ]

C [F]

∗ The BA7795FS has a different pin layout to the BA7795LS.

Fig. 3 Signal flow for EE / recording

6

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