Video ICs
CTL recording / playback amplifier
for VHS VCRs
BA8400FV
The BA8400FV is a CTL recording / playback amplifier developed for VHS VCRs. The playback amplifier has an
AGC circuit that can handle large input signal fluctuations, and a recording / playback switching circuit is provided to
allow high-speed switching.
•
Applications
VHS-format VCRs
•
Featuresoperated off low power supply voltage (2.7V
1) Can be
to 3.5V).
2) Playback amplifier with AGC.
3) Fast switching between recording and playback.
•
Block diagram
MONI OUT
HysBIAS
FILTER
14
13
12
11
10
9
8
P
RECPBGND
7
Ref
R
CTL –
6
BIAS
AGC
IN –
AMP
CTL +
5
P
V
CC
DET
REC
AMP
R
P
1
2
SW
3
CTL OUT
RECHPB
RECIN
GND
4
R
AGC
1
Video ICs
BA8400FV
•
Pin descriptions
Pin No.
1
Pin name
CTL OUT
(CTL pulse output)
RECHPB
(record / play switch)
RECIN
(REC CTL pulse input)
GND
CTL +
(CTL head “+” input)
CTL –
(CTL head “–” input)
RECPBGND
BIAS
(bias)
IN –
(playback amplifier input)
Function
CTL pulse output.
High output level approx. V
CC
– 0.05V, I
O
= + 0.5mA
Low output level approx. 0.05V, I
O
= – 0.5mA
Switch input pin for the record / playback amplifiers.
High input: REC mode
Low input: PB mode
Threshold voltage: approx. 1 / 2V
CC
CTL pulse input pin for recording.
Threshold voltage: approx. 1 / 2V
CC
Power, REC / PB SW, CTL output buffer ground pin.
When recording: CTL head positive-side recording current.
When playing: input pin for the playback CTL pulse.
When recording: CTL head negative-side recording current.
When playing: bias pin for the playback CTL pulse input.
Ground pin for the REC and playback amplifiers.
Bias pin for the playback amplifier.
Bias voltage: VIB8 = 0.15V
CC
+ 1.3V (approx.)
Feedback input pin for the playback amplifier.
2
3
4
5
6
7
8
9
10
MONIOUT
Playback amplifier output monitor pin.
(playback amplifier output) Output dynamic range is the DC level
±
Vf.
AGC
(AGC time constant)
HysBIAS
(hysteresis amplifier
center level)
FILTER
(high-frequency
noise filter)
V
CC
Set the time constant after considering the transient response of the playback
mode switching.
AGC detect level VdetAGC = 0.47V
CC
[V] (approx.)
Playback amplifier output amplitude VAGC = 2
×
(VdetAGC – HysVcent) [V
P-P
]
Connection pin for the bypass capacitor for the hysteresis amplifier center level.
Pin for connection of high-frequency noise filter for AGC amplifier output for
playback CTL pulse. Also, input pin for the hysteresis amplifier. Hysteresis
amplifier center voltage HysVcent = 0.27Vcc [V] approx.
High-side hysteresis width
∆HysVH
= 0.367V
CC
– HysVcent [V]
Low-side hysteresis width
∆HysVL
= 0.173V
CC
– HysVcent [V]
Connect a decoupling capacitor close to the pin.
11
12
13
14
•
Absolute maximum ratings (Ta = 25°C)
Parameter
Power supply voltage
Power dissipation
Operating temperature
Storage temperature
Symbol
V
CC
Pd
Topr
Tstg
Limits
8.0
450
∗
– 25 ~ + 75
– 55 ~ + 125
Unit
V
mW
°C
°C
•
Recommended operating conditions (Ta = 25°C)
Parameter
Symbol
V
CC
Applied voltage
Not designed for radiation resistance.
∗
Reduced by 4.5mW for each increase in Ta of 1
°C
over 25°C.
Limits
Unit
V
2.7 ~ 3.5
2
Video ICs
BA8400FV
CC
•
Electrical characteristics (unless otherwise noted, Ta = 25°C and V
Parameter
Circuit current
〈AGC
amplifier〉
AGC amplifier gain
Input bias voltage
Pin 5 input resistance
AGC control sensitivity
Output amplitude
〈Hysteresis
amplifier〉
Hysteresis width
CTLOUT output high level voltage
CTLOUT output low level voltage
〈REC
amplifier〉
Recording current
Max. output high level voltage
Max. output low level voltage
Threshold voltage
Input resistance
〈REC
/ PB switch〉
Threshold voltage
REC to PB switching time
Vth2
TR – P
1.0
—
1.5
—
Irec
VOHR
VOLR
Vth3
Z
IN
3
±
1.3
2.0
—
1.0
24
±
2.5
2.8
0.2
1.5
30
∆HysV
VOHP
VOLP
±
250
2.0
—
±
290
2.8
0.2
GVagc
VIB8
Z
IN
5
∆AGC
/ V
VAGC
2.5
1.35
1.6
–2
0.88
4.5
1.7
2.0
0
1.1
Symbol
I
CC
Min.
—
Typ.
3.5
= 3V)
Unit
mA
Conditions
No signal, CTLOUT: High
Max.
7.0
6.5
2.05
2.4
+2
1.32
±
330
—
1.0
±
3.7
—
1.0
2.0
36
dB
V
kΩ
dB
V
P-P
—
—
—
V
IN
= 0.15→1.0V
P-P
f = 300Hz, V
IN
= 300mV
P-P
mV
V
V
I
O
= – 0.5mA
I
O
= + 0.5mA
—
mA
V
V
V
kΩ
R
O
= 400 W
I
O
= – 0.5mA
I
O
= + 0.5mA
—
—
2.0
100
V
ms
∗
See note below
—
∗
Note: The switching time from REC to PB is the time until CTLOUT is output.
5
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