1
Video ICs
2-channel PRE / REC amplifier with
auto-tracking interface
BA7182AS
The BA7182AS is a PRE / REC amplifier developed for use in video cassette recorders. It has been designed for use
in two-head decks and features built-in FB damping, two preamplifiers, a chroma output amplifier, an FM output
amplifier (with AGC), an envelope detector, a constant-current BTL-drive REC amplifier (with AGC) and built-in chan-
nel and REC / PB switches on a single monolithic IC.
Applications
VCRs
Features
1) The playback amplifier has a total gain of 59dB
(Typ.), and has a low-noise preamplifier. Designed
for VHS-band operation with low external parts
count. The IC has 2 circuits for 2-head VCR applica-
tions.
2) Two playback output systems (throgh output and
AGC output). The AGC output level is 270mV
P-P
(Typ.) ; suitable for FM brightness signal output.
3) Auto-tracking interface for automated tracking
adjustment. An integrate and hold detector is used
to reduce the load on the microcontroller.
4) The recording amplifier uses constant-current BLT
drive that handles load variations (i.e. headimped-
ance) well, and gives stable recording characteris-
tics. A single circuit is provided for 2-head VCR use.
5) Built-in recording level AGC means adjustment of
FM recording current is not necessary.
6) Head switches for 2-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)
Parameter
Symbol
Limits
Unit
7.0
V
mW
Topr
C
Tstg
C
V
CC
1100
Pd
20 ~ + 75
55 ~ + 125
Applied voltage
Power dissipation
Operating temperature
Storage temperature
Reduced by 11mW for each increase in Ta of 1
C over 25
C (free air).
Parameter
Symbol
Min.
Typ.
Max.
Unit
Conditions
V
CC
4.5
5.0
5.5
V
12pin
Playback / recording
Not designed for radiation resistance.
2
Video ICs
BA7182AS
Block diagram
22
1
2
3
4
5
6
7
8
9
10
11
21
20
19
18
17
16
15
14
13
12
GND 2
V
CC
+
REC OUT
DET
HPF
AGC
1k
REC
PRE
PRE
DET
AGC
+
HPF
DET
RF
DFF IN
DET FILTER
HOLD FILTER
REC DCFB
PRE IN 1
PRE IN 2
GND 1
REC AGC FILTER
REC LEVEL ADJ
H SYNC IN
(REC OUT 1)
(REC OUT 2)
V
CC
REC EQ
PB AGC OUT
PB / EE / REC CTRL
REC IN
PB AGC FILTER
PB RF OUT
AT ENVE DET ADJ
AT ENVE HOLD OUT
EP / SP CTRL
S / H
PRE / REC
LOGIC
MUTE
3
Video ICs
BA7182AS
Electrical characteristics (unless otherwise noted, Ta = 25C, V
CC
= 5.0V and f = 4.0MHz)
Parameter
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
Fig.1
Fig.1
Conditions
Playback system
(Pin 15: H)
Quiescent current
Voltage gain ch-1
Voltage gain ch-2
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
PRE ch 2 holding voltage
PRE ch 1 holding voltage
ENVE output level SP-2
ENVE sensitivity curve
ENVE saturation voltage
ENVE residual voltage
EP mode holding voltage
SP mode holding voltage
No signal
Pin 5 input = 0.3mV
P-P
, pin 1: L,
pin 18 output measurement
Pin 7 input = 0.3mV
P-P
, pin 1: H,
pin 18 output measurement
Difference in pin 18 output level 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,
guaranteed design value.
When pin 18 output 2nd harmonic distortion is
30dBc
Difference in pin 18 output level for pin 1: H / L.
Pin 18 output DC offset for pin 1: H / L.
Rg = 10
, input conversion of pin 18 output
noise, guaranteed design value.
V
IN
= 0.3mV
P-P
Pin 14 output measurement
Pin 14 output level difference for V
IN
= 0.15 and 0.6mV
P-P
Difference in pin 14 output level for f = 8.0 / 1.0MHz
V
IN
= 0.3mV
P-P
.
Pin 8 impedance
Pin 1 DC voltage for ch 2 operation
Pin 1 DC voltage for ch 1 operation
Pin 20 output measurement when pin 21 = L
and pin 18 output = 250mV
P-P
Pin 21 = L, Pin 20 output measurement for large signal
Pin 21 = L, Pin 20 output measurement for no signal
Pin 21 DC voltage for EP mode
Pin 21 DC voltage for SP mode
--
Symbol
Min.
Typ. Max.
Unit
--
26
42
mA
G
VP1
56.5
59
61.5
dB
G
VP2
56.5
59
61.5
dB
G
VP
1
0
1
dB
G
Vf
6
3
1
dB
2HD
P
--
45 35
dBc
3HD
P
--
50 35
dBc
V
OMP
1.0
1.5
--
V
P-P
CT
P
--
38 33
dBc
V
ODC
150
0
150
mV
P-P
V
NIN
--
0.25
1.0
V
rms
V
AGC
220
270
320
V
AGC
--
0.3
2
dB
G
VAF
2
0.5
2
dB
R
ON8
--
5
10
V
TH1H
3.5
--
V
CC
V
V
TH1L
0
--
1.2
V
V
EN-S2
1.4
2.2
3.0
V
P
CRV
150
200
250
%
V
EN-MA
4.6
4.9
--
V
--
0.1
0.4
V
V
TH21H
3.5
--
V
CC
V
V
TH21L
0
--
1.2
V
V
EN-MI
I
q (P)
mV
P-P
G
VP
= G
VP1
G
VP2
4
Video ICs
BA7182AS
(unless otherwise noted, Ta = 25C, V
CC
= 5.0V, f = 4.0MHz and I
OAR
= 36mA
P-P
)
Parameter
Symbol
Min.
Typ.
Max.
Unit
Conditions
Recording system
(Pin 15: L)
Quiescent current
Recording AGC level
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
Frequency characteristic
AGC mode holding voltage
AGC mode holding voltage
PB mode holding voltage
EE mode holding voltage
REC mode holding voltage
Note: dBc: dB below carrier (used to express relative level from carrier reference for convenience sake)
No signal
Pin 16 input = 400mV
P-P,
pin 8 output measurement
Pin 8 output level difference for f = 4.0MHz,
pin 16 input = 225mV
P-P
to 800mV
P-P
.
Pin 8 output level difference for f = 8.0 / 1.0MHz,
pin 16 input = 400mV
P-P
Pin 16 input = 400mV
P-P
, 8.0MHz spurious.
Pin 16 input = 400mV
P-P
, 12.0MHz spurious,
guaranteed design value.
4.0MHz
630kHz spurious, guaranteed design value.
When pin 8 output 2nd harmonic distortion is 30dB
Pin 8 output level difference for load L: 8.2 ~ 12
H
Pin 8 output level difference for pin 15: M / H.
Pin 8 output level difference for f = 8.0 / 1.0MHz, AGC OFF
Pin 11 DC voltage to maintain recording AGC operation
Pin 11 DC voltage to maintain recording AGC stopped
Pin 15 DC voltage for PB mode
Pin 15 DC voltage for REC MUTE mode
Pin 15 DC voltage for REC mode
Measurement
circuit
72
108
mA
Fig.2
36
42
mA
P-P
Fig.2
0.15
2
dB
Fig.2
0
2
dB
Fig.2
41
35
dBc
Fig.2
50
40
dBc
Fig.2
43
38
dBc
Fig.2
50
--
mA
P-P
Fig.2
0.35
--
dB
Fig.2
44
38
dBc
Fig.2
7.8
10.3
dB
Fig.2
--
V
CC
V
Fig.2
--
1.2
V
Fig.2
--
V
CC
V
Fig.2
--
2.8
V
Fig.2
--
30
--
2
--
--
--
42
2
--
5.3
2.7
0
3.8
2.2
0
--
1.2
V
Fig.2
I
OAR
I
OAR
I
OAF
2HD
R
3HD
R
CMD
R
I
OMR
I
ORL
MU
R
I
OEQ
V
TH11H
V
TH11L
V
TH15H
V
TH15M
V
TH15L
I
q (R)
5
Video ICs
BA7182AS
22
1
2
3
4
5
6
7
8
9
10
11
21
20
19
18
17
16
15
14
13
12
DET
HPF
AGC
1k
REC
PRE
PRE
DET
AGC
+
+
HPF
DET
RF
2.0V
0.1
0.1
0.1
0.1
0.022
1k
10
1k
10
0.1
0.1
0.1
0.1
0.1
0.1
36k
390k
H SYNC IN
REC LEVEL ADJ
PRE IN 2
PRE IN 1
DFF IN
PRE / REC
V
CC
AT ENVE HOLD OUT
AT ENVE DET ADJ
PB RF OUT
REC IN
PB / EE / REC CTRL
PB AGC OUT
33k
3k
300
S / H
LOGIC
MUTE
5V
0.01
L: REC MUTE
L: REC START
EP / SP CTRL
L: SP
68p
R [
]
C [F]
L [H]
V
CC
Fig. 1
Units:
Measurement circuits
(Playback system)
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