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
•1)Features
Can be operated off low power supply voltage (2.7V
to 3.5V).
2) Playback amplifier with AGC.
3) Fast switching between recording and playback.
BIAS
9
8
IN –
MONI OUT
10
P
R
P
R
1
2
3
4
5
6
7
CTL OUT
RECHPB
RECIN
GND
CTL +
CTL –
RECPBGND
SW
R
P
REC
AMP
AGC
AMP
Ref
DET
11
AGC
HysBIAS
12
13
14
VCC
FILTER
•Block diagram
1
Video ICs
BA8400FV
•Pin descriptions
Pin No.
Pin name
Function
CTL pulse output.
High output level approx. VCC – 0.05V, IO = + 0.5mA
Low output level approx. 0.05V, IO = – 0.5mA
Switch input pin for the record / playback amplifiers.
High input: REC mode
Low input: PB mode
Threshold voltage: approx. 1 / 2VCC
1
CTL OUT
(CTL pulse output)
2
RECHPB
(record / play switch)
3
RECIN
(REC CTL pulse input)
4
GND
5
CTL +
(CTL head “+” input)
When recording: CTL head positive-side recording current.
When playing: input pin for the playback CTL pulse.
6
CTL –
(CTL head “–” input)
When recording: CTL head negative-side recording current.
When playing: bias pin for the playback CTL pulse input.
7
RECPBGND
8
BIAS
(bias)
Bias pin for the playback amplifier.
Bias voltage: VIB8 = 0.15VCC + 1.3V (approx.)
9
IN –
(playback amplifier input)
Feedback input pin for the playback amplifier.
10
CTL pulse input pin for recording.
Threshold voltage: approx. 1 / 2VCC
Power, REC / PB SW, CTL output buffer ground pin.
Ground pin for the REC and playback amplifiers.
MONIOUT
Playback amplifier output monitor pin.
(playback amplifier output) Output dynamic range is the DC level ± Vf.
11
AGC
(AGC time constant)
Set the time constant after considering the transient response of the playback
mode switching.
AGC detect level VdetAGC = 0.47VCC [V] (approx.)
Playback amplifier output amplitude VAGC = 2 × (VdetAGC – HysVcent) [VP-P]
12
HysBIAS
(hysteresis amplifier
center level)
Connection pin for the bypass capacitor for the hysteresis amplifier center level.
13
FILTER
(high-frequency
noise filter)
14
VCC
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 = 0.367VCC – HysVcent [V]
Low-side hysteresis width ∆HysVL = 0.173VCC – HysVcent [V]
Connect a decoupling capacitor close to the pin.
•Absolute maximum ratings (Ta = 25°C)
Parameter
Symbol
Limits
Unit
Power supply voltage
VCC
8.0
V
Power dissipation
Pd
450∗
mW
Operating temperature
Topr
– 25 ~ + 75
°C
Storage temperature
Tstg
– 55 ~ + 125
°C
∗ Reduced by 4.5mW for each increase in Ta of 1 °C over 25°C.
•Recommended operating conditions (Ta = 25°C)
Parameter
Symbol
Limits
Unit
VCC
2.7 ~ 3.5
V
Applied voltage
䊊Not designed for radiation resistance.
2
Video ICs
BA8400FV
•Input / output circuits
Vcc
Vcc
25k
Vcc
2
1
30k
RECPB
CTLOUT
1k
25k
Fig.1
Fig.2
Vcc
Vcc
25k
CTL +
5
3
2k
30k
RECIN
6
CTL –
25k
Fig.3
Fig.4
Vcc
22k
BIAS
8
45k
30k
4k
Fig.5
3
Video ICs
BA8400FV
CTL +
5
Vcc
22k
45k
30k
2k
1.7V
4k
1.7V
10
100
100
9
IN –
Fig.6
MONIOUT
Vcc
15.9k
14.1k
1k
5.6k
11
AGC
Fig.7
Vcc
19k
2.9k
2.9k
5.2k
13
FILTER
12
HysBIAS
4
Fig.8
Video ICs
BA8400FV
•Electrical characteristics (unless otherwise noted, Ta = 25°C and V
Parameter
CC
= 3V)
Symbol
Min.
Typ.
Max.
Unit
ICC
—
3.5
7.0
mA
AGC amplifier gain
GVagc
2.5
4.5
6.5
dB
—
Input bias voltage
VIB8
1.35
1.7
2.05
V
—
Pin 5 input resistance
ZIN5
1.6
2.0
2.4
kΩ
—
AGC control sensitivity
∆AGC / V
Circuit current
Conditions
No signal, CTLOUT: High
〈AGC amplifier〉
+2
dB
VIN = 0.15→1.0VP-P
VAGC
0.88
1.1
1.32
VP-P
f = 300Hz, VIN = 300mVP-P
Hysteresis width
∆HysV
± 250
± 290
± 330
mV
CTLOUT output high level voltage
VOHP
2.0
2.8
—
V
IO = – 0.5mA
CTLOUT output low level voltage
VOLP
—
0.2
1.0
V
IO = + 0.5mA
± 1.3
± 2.5
± 3.7
mA
RO = 400 W
2.0
2.8
—
V
IO = – 0.5mA
IO = + 0.5mA
Output amplitude
–2
0
〈Hysteresis amplifier〉
—
〈REC amplifier〉
Recording current
Irec
Max. output high level voltage
VOHR
Max. output low level voltage
VOLR
—
0.2
1.0
V
Threshold voltage
Vth3
1.0
1.5
2.0
V
—
Input resistance
ZIN3
24
30
36
kΩ
—
Vth2
1.0
1.5
2.0
V
TR – P
—
—
100
ms
〈REC / PB switch〉
Threshold voltage
REC to PB switching time
—
∗See note below
∗ Note: The switching time from REC to PB is the time until CTLOUT is output.
5
Video ICs
BA8400FV
•Measurement circuit
VCC
SW1
A
a
b
c
P
1
Is1
V
Am14
14
R
Vm1
SW13a
2
Am2
A
V
SW2
a
b
1000p
+
c
Is2
+
VCC
a
b
4.7k
REC
AMP
SW3
d
c
+
4
DET
10µ
11
1µ
Vm3 Vs3
R
VCC
400
10
SW10
a
V
Vm5
R
A Am56
+
AMP
+
–
6
10µ
OSC
V
1M
P
c
Is5
+
AGC
5
b
SW12
–
V
SW5
Vs13
270k
12
A Am3
V
Vm13
–
3
a
SW13b
13
SW
V
b
330k
Vm10
12k
9
P
V
910
820
Vm6
a
7
Ref
b
8
SW9
+
+
1µ
Fig.9
6
V
10µ
Vm8
Video ICs
BA8400FV
•Measurement conditions (unless otherwise noted, Ta = 25°C and V
CC
= 3V)
Switch position
Parameter
Symbol
Monitor SW
1
SW SW SW
2
3
5
ICC
Am14
a
a
a
a
a
a
ON OFF OFF
AGC amplifier gain
GVagc
Vm13
a
a
a
c
b
b
OFF ON OFF
Input bias voltage
VIB8
Vm8
a
a
a
a
a
a
ON OFF OFF
Pin 5 input resistance
ZIN5
Vm5
a
b
b
b
a
a
ON OFF OFF
AGC control sensitivity
∆AGC / V
13pin
a
a
a
c
a
b
ON OFF OFF
Circuit current
Notes
SW SW SW SW SW
9
10 12 13a 13b
—
〈AGC amplifier〉
∗1. f = 300Hz,
VIN = 50mVP-P
—
∗2.
∗3. f = 300Hz,
VIN = 0.15 / 1.0VP-P
∗4. f = 300Hz,
VAGC
13pin
a
a
a
c
a
b
ON OFF OFF
Hysteresis width
∆HysV
Vm1
a
a
a
a
a
a
ON OFF
b
∗5.
CTLOUT output voltage H
VOHP
Vm1
c
a
a
a
a
a
ON OFF
b
IO = – 0.5mA, Vs13 = 1.5V
CTLOUT output voltage L
VOLP
Vm1
c
a
a
a
a
a
ON OFF
b
IO = + 0.5mA, Vs13 = 0V
Recording current 5
Irec5
Am56
a
b
b
a
a
a
ON OFF OFF
—
Recording current 6
Irec6
Am56
a
b
a
a
a
a
ON OFF OFF
—
Max. output voltage "H"
VOHR
Vm1
c
b
b
a
a
a
ON OFF OFF
IO = – 0.5mA
Max. output voltage "L"
VOLR
Vm1
c
b
a
a
a
a
ON OFF OFF
IO = + 0.5mA
Vth3
Vm3
a
b
c
a
a
a
ON OFF OFF
Output amplitude
VIN = 300mVP-P
〈Hysteresis amplifier〉
〈REC amplifier〉
Input threshold voltage
Input resistance
ZIN3
Vm3
a
b
d
a
a
a
ON OFF OFF
Vth2
Vm2
a
c
a
a
a
a
ON OFF OFF
—
∗6.
〈REC / PB switch〉
Threshold voltage
REC to PB switching time
TR-P
1pin
a
ba
a
c
a
a
ON OFF OFF
—
∗6.
Measurement method
∗1 Input a sine wave of f = 300Hz to pin 5, and measure the output amplitudes on pins 10 and 13 (Vo10 and Vo13).
The AGC gain is given by: Gvagc = 20log (Vo13 / Vo10) [dB].
∗2 Measure the output voltages Vo0 and Vo.5 on pin 5 when currents of Is5 = 0, and Is5 = 0.5mA are applied.
The input resistance is given by: ZIN5 = {0.0005 / (Vo.5 Vo0) 1 / 400} –1 [Ω]
∗3 Input a sine wave of f = 300Hz to pin 5. Adjust the input level until the output amplitude on pin 10 is 0.15VP-P and 1.0VP-P, and measure the corresponding output amplitudes on pin 13 (Vo0.15 and Vo1.0).
The AGC control sensitivity is given by: ∆AGC / V = 20log (Vo1.0 / Vo0.15) [dB].
∗4 Input a sine wave of f = 300Hz to pin 5. Adjust the input level until the output amplitude on pin 10 is 300mVP-P.
Measure the output amplitude on pin 13.
∗5 With pin 13 floating, measure the output voltage Vocent.
Increase Vs13 from 0V, and record VINH as the Vs13 voltage when the pin 1 output exceeds 2.8V.
Decrease Vs13 from 1.5V, and record VINL as the Vs13 voltage when the pin 1 output goes below 0.2V.
High-side hysteresis width ∆HysVH = VINH Vocent [VP-P]
Low-side hysteresis width ∆HysVL = VINL Vocent [VP-P]
∗6 Measure the currents IIN2.7 and IIN3.0 on pin 3 when voltages Vs3 of 2.7V and 3.0V respectively are applied.
The input resistance is given by: ZIN3 = 0.3 / (IIN3.0 IIN2.7) [Ω]
∗7 Input a square wave of 300Hz, VIN = 20mVP-P to pin 5, and measure the time that it takes CTLOUT to be output after pin 2 goes from VCC to 0V.
7
Video ICs
BA8400FV
•Application example
VCC 3.0V
CTL OUT
1
14
P
+
R
33µF
RECHPB
2
FILTER
13
SW
1000pF
RECIN
+
–
3
HysBIAS
12
+
22µF
REC
AMP
+
–
4
GND
DET
AGC
11
+
1µF
1MΩ
AGC
R
CTL +
5
10
P
MONI OUT
330kΩ
AMP
+
–
R
IN –
6
9
P
CTL –
910Ω
+
10µF
RECPBGND
7
Ref
BIAS
8
+
1µF
Fig.10
8
Video ICs
BA8400FV
•External dimensions (Units: mm)
8
1
7
0.65
0.15 ± 0.1
4.4 ± 0.2
0.1
1.15 ± 0.1
6.4 ± 0.3
5.0 ± 0.2
14
0.22 ± 0.1
0.3Min.
0.1
SSOP-B14
9