ROHM BA7796FS Datasheet
1
Video ICs
VCR standard audio signal processor
BA7796FS
The BA7796FS is a standard audio signal processor designed for use in VCRs and tape decks. The circuit is comprised of a playback preamplifier, a line amplifier, a recording amplifier, an ALC circuit, an EQ switch, and high-voltage head switch.
The IC has three input switching systems, and a built-in coil equivalent circuit for recording equalization, which eliminates the need for an external component.
•
Applications
Video cassette recorders and tape decks
•
Features
1) Three input switching systems built-in (LINE1,
LINE2, and TUNER).
2) Built-in coil equivalent circuit for recording equalization.
3) Two-mode EQ switch.
4) High-performance low-noise playback amplifier.
5) Fixed ALC level ( – 7.2dB when V
CC = 12V).
6) Phase-inverting recording amplifier.
•
Absolute maximum ratings (Ta = 25°C)
•
Recommended operating conditions (Ta = 25°C)
Parameter Symbol Limits Unit
V
CC
13 V
Pd 800
∗
mW
Topr °C
Tstg °C
– 10 ~ + 65
– 55 ~ + 125
Power supply voltage
Power dissipation
Operating temperature
Storage temperature
∗
When mounted on a 90mm × 50mm × 1.6mm glass epoxy board.
Reduced by 8.0mW for each increase in Ta of 1°C over 25°C.
Parameter Symbol Min. Typ. Max. Unit
V
CC
7.5 — 12.5 VPower supply voltage
2
Video ICs BA7796FS
•
Block diagram
LINE
ALC
PB
PB
REC
REC
SP
0dB
EQ
REC AMP
BUFF
MUTE
+ 28dB
12
11
10
9
8
7
6
5
4
3
2
1
24
23
22
21
20
19
18
17
16
15
14
13
HEAD EQ SW
PB IN
REC HEAD SW
REC OUT
REC L2
REC L1
EQ CTRL
V
CC
RIPPLE FILTER
REC / EE CTRL
LINE OUT
GND
HEAD GND
PB NFB
PB EQ SW
PB OUT
PB LINE IN
ALC FILTER
TUNER IN
INPUT SW CTRL
LINE IN1
PB / EE CTRL
LINE IN2
MUTE CTRL
LP + EP
ATT
–
8dB
ATT
–
8dB
ATT
–
8dB
C [F]
Units: R [Ω]
3
Video ICs BA7796FS
•
Pin descriptions
I / O circuit
1 2.0V
REC: 120kΩ
REC: 11
Ω
2 0.0V
3 0.0V
REC: OPEN
4 5.7V EF (P - P)
5 5.7V
6 5.7V
7 —
8V
CC
12.0V —
9 12.0V 10k
Ω (V
CC)
10 —
11 5.7V
12 GND 0.0V —
13 —
14 5.6V 120k
Ω
15 —
16 5.6V 120k
Ω
17 —
18 5.6V 120k
Ω
19
PB: 0.0V
PB: not fixed
20 5.6V 120k
Ω
21 2.0V
22 2.0V
23 2.0V
24 0.0V —
Pin No.
HEAD EQ SW
PB IN
REC HEAD SW
REC OUT
REC L2
REC L1
EQ CTRL
RIPPLE FILTER
REC / EE CTRL
LINE OUT
MUTE CTRL
LINE IN2
PB / EE CTRL
LINE IN1
INPUT SW CTRL
TUNER IN
ALC FILTER
PB LINE IN
PB EQ SW
PB OUT
PB NFB
HEAD GND
EF (P - P)
EF (P - P)
B (NPN)
B (NPN)
REC: 11
Ω (ON)
220kΩ
/ 20
Ω (ON)
EF (NPN) ~ 100Ω
35
Ω (ON) / OPEN
19Ω (ON) / OPEN
Pin voltagePin name Function
See input / output circuit
See input / output circuit
See input / output circuit
See input / output circuit
See input / output circuit
Playback amplifier input / playback head switch
Head resonance capacitor switch
High-withstanding voltage recording head switch
Recording amplifier output
Recording EQ switch
Recording EQ pin
EQ control
V
CC
Ripple filter
REC / EE control
Line amplifier output
GND
Mute control
Line input 2
PB / EE control
Line input 1
Input switch control
Tuner input
For setting the time constant for the ALC filter
(attack and recovery times)
Line input for playback
Playback amplifier output
Playback equalizer switch
Playback amplifier feedback
GND for playback amplifier and head switch
∗
EF: emitter follower, P-P: push pull, B: base, and C: collector.
All measurements made using the measurement circuit (Fig. 1) with V
CC = 12V and quiescent circuit conditions.
All numerical values are standardized values.
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