1
Video ICs
VCR standard audio signal processor
BA7797F
The BA7797F is 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 and high-voltage head switch.
The IC has a built-in coil equivalent circuit for recording equalization, which eliminates the need for an external com-
ponent.
Applications
Video cassette recorders and tape decks
Features
1) Two input switching systems built-in (LINE and TUN-
ER).
2) Built-in coil equivalent circuit for recording equaliza-
tion.
3) High-performance low-noise playback amplifier.
4) ALC level can be adjusted by connection of an
external resistor.
5) Compatible with single-mode EQ making it ideally
suited to widely-used decks.
Block diagram
LINE
ALC
PB
REC
REC
0dB
EQ
REC AMP
BUFF
MUTE
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
GND
+ 28dB
V
CC
PB IN
REC HEAD SW
REC OUT
REC L
RIPPLE FILTER
REC / EE CTRL
LINE OUT
ALC LEVEL ADJ
PB NFB
PB OUT
PB LINE IN
ALC FILTER
TUNER IN
PB / TU / LINE CTRL
LINE IN
MUTE CTRL
ATT
8dB
ATT
8dB
2
Video ICs
BA7797F
Absolute maximum ratings (Ta = 25C)
Parameter
Symbol
Limits
Unit
V
CC
13
V
550
mW
Topr
C
Tstg
C
Pd
10 ~ + 65
55 ~ + 125
Power supply voltage
Power dissipation
Operating temperature
Storage temperature
When mounted on a 50mm
50mm
1.6mm glass epoxy board. Reduced by 5.5mW for
each increase in Ta of 1
C over 25
C.
Recommended operating conditions (Ta = 25C)
Parameter
Symbol
Min.
Typ.
Max.
Unit
V
CC
7.5
--
12.5
V
Power supply voltage
Pin descriptions (V
CC
= 10V)
1
PB IN
2.0V
REC: 120k
REC: 11
2
REC HEAD SW
0.0V
REC: OPEN
3
REC OUT
4.7V
EF (P-P)
4
REC L
4.7V
B (NPN)
5
V
CC
10.0V
--
6
RIPPLE FILTER
10.0V
10k
(V
CC
)
7
REC / EE CTRL
--
8
LINE OUT
4.7V
EF (P-P)
9
ALC LEVEL ADJ
4.1V
10
MUTE CTRL
--
11
LINE IN
4.7V
120k
12
PB / TU / LINE CTRL
--
13
TUNER IN
4.7V
120k
14
ALC FILTER
PB: 0.0V
15
PB LINE IN
4.7V
120k
16
PB OUT
2.0V
EF (P-P)
17
PB NFB
2.0V
B (NPN)
18
GND
0.0V
--
Pin No.
Pin name
Function
Pin voltage
I / O circuit
REC: 17
(ON)
EF (NPN) ~ 100
PB: Not fixed
See input / output circuit
See Fig. 4
See input / output circuit
See input / output circuit
Playback amplifier input / playback head switch
High-withstanding voltage recording head switch
Recording amplifier output
Recording EQ switch
V
CC
Ripple filter
REC / EE control
Line amplifier output
ALC level adjustment
Mute control
Line input
PB / TU / LINE control
Tuner input
For setting the time constant for the ALC filter
(attack and recovery times)
Line input for playback
Playback amplifier output
Playback amplifier feedback
GND
EF: emitter follower, P-P: push pull, B: base, and C: collector.
All measurements made using the measurement circuit (Fig.1) with V
CC
= 10V and quiescent circuit conditions.
All numerical values are standardized values.
3
Video ICs
BA7797F
Input / output circuits
H
L
CTRL
56k
REC
AMP
PB
HEAD SW
7
REC / EE
REC / EE CTRL 7
M
56k
MUTE
CTRL
10
MUTE CTRL 10
H
L
56k
CTRL
12
PB / TU / LINE CTRL 12
PB / TU / LINE
4
Video ICs
BA7797F
Electrical characteristics (unless otherwise noted, Ta = 25C, V
CC
= 10V, and f = 1kHz)
Parameter
Symbol
Min.
Typ.
Max.
Unit
Conditions
I
qEE
6.4
8.5
11.3
mA
I
qPB
6.4
8.5
11.3
mA
I
qREC
5.2
6.9
9.2
mA
G
VCLP
27.0
28.0
29.0
dB
G
VCLT
19.0
20.0
21.0
dB
THD
LT
--
0.1
0.3
%
V
OMLT
5.9
8.4
--
dBV
V
NOLT
--
81.5
75
dBV
V
OA
9.0
8.0
7.0
dBV
THD
A
--
0.1
0.5
%
MT
--
82.0
72
dB
G
VCR
19.0
20.0
21.0
dB
THD
R
--
0.13
0.4
%
V
OMR
5.7
8.2
--
dBV
G
VOR
60
71
--
dB
G
VOP
61
68
--
dB
V
NINP
--
122.5 114
dBV
G
VCP
35.0
36.0
37.0
dB
R
PH
--
11
20
R
RH
--
17
25
BV
RHDC
--
0
10
A
E
2
=
55V
BV
RHAC
80
100
--
V
P-P
Measurement
circuit
Fig.1
Fig.1
Fig.1
Fig.1
Fig.1
Fig.1
Fig.1
Fig.1
Fig.1
Fig.1
Fig.1
Fig.1
Fig.1
Fig.1
Fig.1
Fig.1
Fig.1
Fig.1
Fig.1
Fig.1
Fig.1
V
O
= 8dBV
V
O
= 8dBV
V
O
= 8dBV, R
L
= 4.7k
THD = 1%, R
L
= 4.7k
V
O
= 0dBV, DIN AUDIO
LINE IN, TUNER IN
REC OUT
V
O
= 8dBV
V
IN
= 25dBV, R
L
= 4.7k
V
O
= 8dBV, R
L
= 4.7k
THD = 1%, R
L
= 4.7k
Rg = 680
, DIN AUDIO
PB IN
PB OUT
f = 70kHz, V
2
1.5V
Rg = 4.7k
, DIN AUDIO
V
IN
= 25dBV, 9pin: OPEN
Fig.2
Measured at BW = 400Hz to 30kHz.
Quiescent current EE
Quiescent current PB
Quiescent current REC
Line amplifier
Voltage gain (PB input)
Voltage gain (LINE1, LINE2, TU inputs)
Distortion
Maximum output level
Output residual noise
ALC level
ALC distortion
Mute attenuation ratio
Recording amplifier
Voltage gain
Distortion
Maximum output level
Openloop gain
Playback preamplifier
Openloop gain
Input conversion noise
Voltage gain (stand alone)
Head switch
PB head switch impedance
REC head switch impedance
REC head switch DC withstanding voltage
REC head switch AC withstanding voltage
No signal
No signal
No signal
5
Video ICs
BA7797F
Measurement circuits
1
2
3
4
5
6
7
8
9
18
17
16
15
14
13
12
11
10
4.7
4.7k
1.5k
12k
6000p
22
CTRL
4.7k
4.7k
0.1
47k
4.7k
0.1
47k
2.2M
22
4.7k
0.1
47k
TUNER IN
22
330
0.01
4.7k
12k
330k
4.7
4.7
REC AMP
EQ
0dB
ALC
LINE
3.3
68k
680
PB IN
REC HEAD SW
REC OUT
V
CC
33
REC / EE
LINE OUT
BUFF
MUTE
PB
REC
ON: Gvo PB
PB OUT
PB LINE IN
ON: ALC OFF
PB / TU / LINE CTRL
LINE IN
MUTE CTRL
REC
ATT
8dB
ATT
8dB
+ 28dB
1800p
Units: R [
]
C [F]
Fig.1
+
+
+
+
+
+
+
+
REC head switch AC withstanding voltage measurement circuit
Fig. 2
1
REC
V
V
2
3
0.1
0.1
BV
RHAC
V
2
e
2
100k
100k
1k
SW
2
REC OUT
PB IN
~
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