1
Video ICs
4-channel PRE / REC amplifier with
auto-tracking interface
BA7184S
The BA7184S is a PRE / REC amplifier developed for use in video cassette recorders. It is compatible with four-head
decks and features built-in FB damping, four preamplifiers, a chroma output amplifier, an FM output amplifier (with
AGC), an envelope detector and envelope comparator, a constant-current BTL-drive REC amplifier (with AGC) and
channel switching, EP / SP switching, and mode switching integrated onto a single monolithic IC.
Applications
VCRs
Features
1) The playback amplifier has a total gain of 56dB
(Typ.), and has a low-noise preamplifier. Designed
for VHS band operation with low external parts
count. The IC has 4 circuits for 4-head VCR applica-
tions.
2) Two playback output systems (through output and
AGC output). The AGC output level is 315mV
P-P
(Typ.); suitable for FM brightness signal output.
3) Auto-tracking interface for automated tracking
adjustment. Linear detector characteristic with sen-
sitivity that can be set using external components.
4) The recording amplifier uses constant-current BLT
drive that handles load variations (i.e. headimped-
ance) well, and gives stable recording characteris-
tics. 2 circuits are provided for 4-head VCR use.
5) Built-in recording level AGC means adjustment of
FM recording current is not necessary.
6) Head switches for 4-channel PRE / REC system
provided.
7) Operates off a single 5V power supply, with low
power dissipation.
Absolute maximum ratings (Ta = 25C)
Recommended operating conditions (Ta = 25C)
Applied voltage
Power dissipation
Operating temperature
Storage temperature
Parameter
1 Reduced by 10.5mW for each increase in Ta of 1
C over 25
C (free air).
Symbol
Limits
V
CC
7.0
1050
1
Topr
Tstg
Unit
V
mW
C
C
Pd
20 ~ + 65
55 ~ + 125
Playback / recording
Parameter
Not designed for radiation resistance.
Symbol
Min.
Typ.
Max.
Unit
Conditions
V
CC
4.5
5.0
5.5
V
13pin
2
Video ICs
BA7184S
Block diagram
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1
0
1
1
1
2
24
23
22
21
20
19
18
17
16
15
14
13
PRE
PRE
ENVE
PRE
PRE
ENVE
RF
DET
PEAK
ENVE
LOGIC
COMP
MUTE
REC
AGC
SP
EP
DET
GND 2
REC LEVEL ADJ
PB AGC OUT
PB RF OUT
AT ENVE PEAKING
AT ENVE OUT
H SYNC IN
DFF IN
ENVE COMP OUT
REC IN
AT ENVE FB
EP / SP CTRL
REC AGC FILTER
REC + OUT 1
GND 1
REC + OUT 2
REC DCFB 2
TP / PB / EE / REC CTRL
PB AGC FILTER
PRE IN 1
PRE IN 2
PRE IN 3
PRE IN 4
V
CC
AGC
(REC - OUT 1)
(REC - OUT 2)
(REC - OUT 3)
(REC - OUT 4)
(REC DCFB 1)
V
CC
3
Video ICs
BA7184S
Electrical characteristics (unless otherwise noted, Ta = 25C, V
CC
= 5.0V and f = 4.0MHz)
Parameter
Symbol
Min.
Typ.
Max.
Unit
Measurement
circuit
--
27
45
mA
Fig. 1
G
VP1
52
56
60
dB
Fig. 1
G
VP2
52
56
60
dB
Fig. 1
G
VP3
52
56
60
dB
Fig. 1
G
VP4
52
56
60
dB
Fig. 1
1.5
-- + 1.5
dB
Fig. 1
8
1.7
--
dB
Fig. 1
--
42
35
dBc
Fig. 1
--
50
35
dBc
Fig. 1
V
OMP
0.8
1.2
--
V
P-P
Fig. 1
CT
P
--
45
30
dBc
Fig. 1
--
--
200
mV
P-P
Fig. 1
V
NIN
--
0.25
1.0
Vrms
Fig. 1
V
AGC
265
315
365
mV
P-P
Fig. 1
--
0.3
2.0
dB
Fig. 1
8
3
--
dB
Fig. 1
R
ON5, 9
--
5
10
Fig. 1
V
ENV1
--
0.7
1.0
V
Fig. 1
V
ENV2
2.4
2.9
3.4
V
Fig. 1
V
ENV3
4.0
4.5
--
V
Fig. 1
V
TH16H
3.5
--
V
CC
V
Fig. 1
V
TH16L
0
--
1.2
V
Fig. 1
V
TH2H
3.5
--
V
CC
V
Fig. 1
V
TH2L
0
--
1.2
V
Fig. 1
V
TH12T
4.1
--
V
CC
V
Fig. 1
V
TH12H
3.0
--
3.7
V
Fig. 1
V
TH12M
1.1
--
2.6
V
Fig. 1
V
TH12L
0
--
0.7
V
Fig. 1
2HD
P
3HD
P
Iq
(P)
G
VP
G
Vf
V
ODC
V
AGC
G
VAF
Supply current
Voltage gain ch-1
Voltage gain ch-2
Voltage gain ch-3
Voltage gain ch-4
Voltage gain differential
Frequency characteristic
2nd harmonic distortion
3rd harmonic distortion
Maximum output level
Crosstalk
Output DC offset
Input conversion noise
AGC output level
AGC control sensitivity
AGC frequency characteristic
PB switch ON resistance
ENVE residual voltage
ENVE output level
ENVE saturation voltage
PRE ch 2 and 4 holding voltage
PRE ch 1 and 3 holding voltage
EP mode holding voltage
SP mode holding voltage
TP mode holding voltage
PB mode holdihg voltage
EE mode holding voltage
REC mode holding voltage
2 Guaranteed design values.
Note: dBc: dB below carrier (used to express relative level from carrier reference for convenience sake)
No signal
Pin 4 input = 0.3mV
P-P
, pin 2: L, pin 16: L,
pin 20 output measurement
Pin 6 input = 0.3mV
P-P
, pin 2: L, pin 16: H,
pin 20 output measurement
Pin 8 input = 0.3mV
P-P
, pin 2: H, pin 16: L,
pin 20 output measurement
Pin 10 input = 0.3mV
P-P
, pin 2: H, pin 16: H,
pin 20 output measurement
G
VP
= G
VP1
G
VP2,
G
VP3
G
VP4
Pin 20 output level difference for f = 8.0 / 1.0MHz,
V
IN
= 0.3mV
P-P
.
V
IN
= 0.3mV
P-P
, 8.0MHz spurious
V
IN
= 0.3mV
P-P
, 12.0MHz spurious
2
When pin 20 output 2nd harmonic distortion is 30dBc
Pin 20 output level difference for pin 2: H / L, pin 16: H / L.
Pin 20 output DC offset for pin 2: H / L, pin 16: H / L.
Rg = 10
, input conversion of pin 20 output noise
2
V
IN
= 0.3mV
P-P
, pin 21 output measurement
Pin 21 output level differential for V
IN
= 0.15 to 0.6mV
P-P
.
f = 8.0 / 1.0MHz, V
IN
= 0.3mV
P-P
2
Pin 5 and pin 9 impedance
2
Pin 18 output measurement when no signal
Pin 18 output measurement when pin 20
output = 400mV
P-P
Pin 18 output measurement for large signal
Pin 16 DC voltage for ch 2 and 4 operation
Pin 16 DC voltage for ch 1 and 3 operation
Pin 2 DC voltage for EP mode
Pin 2 DC voltage for SP mode
Pin 12 DC voltage for TRICK PLAY mode
Pin 12 DC voltage for PB mode
Pin 12 DC voltage for REC MUTE mode
Pin 12 DC voltage for REC mode
Conditions
Playback system
(Pin 12: H)
4
Video ICs
BA7184S
Parameter
Symbol
Min.
Typ.
Max.
Unit
Conditions
--
67
100
mA
Fig. 2
I
OAR1
27
30
33
mA
P-P
Fig. 2
I
OAR2
24
27
30
mA
P-P
Fig. 2
--
0.3
2.0
dB
Fig. 2
8
3
--
dB
Fig. 2
2HD
R
--
45
35
dBc
Fig. 2
3HD
R
--
50
35
dBc
Fig. 2
CMD
R
--
50
35
dBc
Fig. 2
I
OMR
40
50
--
mA
P-P
Fig. 2
2.0 0.3
--
dB
Fig. 2
MU
R
--
45
35
dBc
Fig. 2
V
TH17H
2.8
--
V
CC
V
Fig. 2
V
TH17L
0
--
1.2
V
Fig. 2
Iq
(R)
I
OAR
I
OAF
I
ORL
Measurement
circuit
No signal
Pin 14 input = 125mV
P-P
, pin 2: L, pin 5
output measurement
Pin 14 input = 125mV
P-P
, pin 2: H, pin 9
output measurement
Pin 14 input = 62.5mV
P-P
, to 250mV
P-P
, pin 5
output level differential
f = 8.0 / 1.0MHz, pin 14 input = 125mV
P-P
,
2
Pin 14 input = 125mV
P-P
, 8MHz spurious
Pin 14 input = 125mV
P-P
, 12.0MHz spurious
2
4.0MHz
630kHz spurious
2
When pin 5 output 2nd harmonic distortion is 30dB
Pin 5 output level difference when load
L: 8.2 and 12
H
2
Pin 5 output level difference for pin 12: M / L
Pin 17 DC voltage to maintain recording
AGC operation.
Pin 17 DC voltage to maintain recording AGC stopped.
Quiescent current
Recording AGC level 1
Recording AGC level 2
AGC control sensitivity
AGC frequency characteristic
2nd harmonic distortion
3rd harmonic distortion
Cross modulation distortion
Maximum output level
Recording current load characteristic
Mute attenuation ratio
AGC mode holding voltage
AGC mode holding voltage
2 Guaranteed design values.
Note: dBc: dB below carrier (used to express relative level from carrier reference for convenience sake)
Recording system
(Pin 12: L)
5
Video ICs
BA7184S
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
PRE
PRE
ENVE
PRE
PRE
ENVE
RF
DET
PEAK ENVE
LOGIC
COMP
MUTE
REC
AGC
SP
EP
DET
0.1
33k
1k
0.1
1k
0.1
PRE IN 3
PRE IN 2
1k
0.1
PRE IN 1
1k
0.1
PRE IN 4
0.1
PB: OPEN
3.9k
68p
390k
0.01
REC IN
H SYNC IN
AT ENVE OUT
AT ENVE
PEAKING
PB RF OUT
PB AGC OUT
33k
EP / SP CTRL
V
CC
DFF IN
ENVE COMP OUT
AGC
0.1
10k
10
10
10
10
REC START ``L''
REC MUTE ``L''
TRICK PLAY ``H''
V
CC
5V
22
C [F]
L [H]
Units: R [
]
Fig. 1
+
Measurement circuits
(Playback system)
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