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Multimedia ICs
Dual Voltage-controlled Amplifier
BA7655A / BA7655AF
The BA7655A and BA7655AF are dual voltage-controlled amplifier ICs designed for use in camcorders and VCRs.
By varying the control voltage the amplifier gain can varied from -6dB to +6dB. When the control pin voltage drops
below 1V the amplifier enters Power Save Mode which mutes the output and reduces the current drawn by the IC.
•
Applications
Video cassette recorders and camcorders
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Features
1) Wide bandwidth.
2) Wide dynamic range.
3) Low power cousumption.
4) Output muting possible.
5) Low voltage gain temperature drift.
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Block diagram
VCA2
VCA1
GNDOUT1CTL1IN1
IN2 CTL2 OUT2
5678
1234
VCC
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Multimedia ICs BA7655A / BA7655AF
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Pin descriptions
Pin name
1 IN1 Input 1
2 CTL1 Control 1
3 OUT1 Output 1
4 GND GND
5 OUT2 Output 2
6 CTL2 Control 2
7 IN2 Input 2
8V
CC Power supply
Pin No. Function
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Input circuits
2, 6
1, 7
3, 5
V
CC
VCC
40k
40k
V
CC
(Typ.)
(Typ.)
3.0V (Typ.)
1m (Typ.)
2.5V
(Typ.)
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Absolute maximum ratings
Parameter Symbol Unit
Power supply voltage V
CCMax. 8.0 V
Power dissipation Pd
500 (BA7655A : DIP8)
∗
1
350 (BA7655AF : SOP8)
∗
2
mW
Operating temperature Topr °C
Storage temperature Tstg °C
– 20 ~ + 80
– 55 ~ + 125
∗
1 Reduced by 5.0mW for each increase in Ta of 1°C over 25°C.
∗
2 Reduce by 3.5mW for each increase in Ta of 1°C over 25°C, when mounted on a 50mm × 50mm.
Limits
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Recommended operating conditions (Ta = 25°C)
Parameter Symbol Limits Unit
Power supply voltage V
CC 4.5 ~ 5.5 V
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Multimedia ICs BA7655A / BA7655AF
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Electrical characteristics (unless otherwise noted , Ta = 25°C , VCC = 5.0V)
䊊 Not designed for radiation resistance.
∗
Items marked with an asterisk are rerference values.
Parameter
Symbol Min. Typ. Max. Unit Voltage Conditions
Supply current
One channel
ICC1 — 4.6 7.0
mA 3.0
Set control voltage to 1V or less,
when only one channel is used.
Both channels
ICC2 — 7.8 12.0
Maximum output voltage
VMax. 2.5 2.8 — V
P-P
5.0
Frequency characteristics
Gf – 1.0 0.0 dB 3.0
Minimum voltage gain
GVMin. – 8.0 – 6.0 – 4.0 dB 2.0 f = 1MHz
Maximum voltage gain
GVMax. 4.0 6.0 8.0 dB 5.0 f = 1MHz
Secondary harmonic distortion
2HD — – 40 — dB 3.0
Audio distortion
AD — 1.0 — % 3.0
Muting output voltage
VMUTE — — 100 mV 1.0 Set control voltage to 1 V or less
V S / N — – 60 — dB 3.0
A S / N — – 60 — dB 3.0
Audio S / N
∗
Video S / N
∗
1.0
f = 1kHz, THD = 1%
f = 13MHz / 1MHz, VIN = 0.5V
P-P
f = 5.0M, VIN = 1V
P-P
f = 1kHz, VIN = 1V
P-P
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Circuit operation
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
POWER SAVE MODE
8
6
4
2
0
–2
–4
–6
–8
–10
–12
–14
Control voltage (V)
GAIN (dB)
Fig. 1 Voltage gain vs.
control voltage characteristics
The gain of a VCA (voltage-controlled amplifier) can be
varied by an external control voltage. By varying the
control voltage from 2V to 5V (in the case of a 5V
power supply), the gain of the amplifiers in this IC can
be varied over the range -6dB to +6dB (see Figs. 1
and 2 below).
When only one of the two amplifiers is being used, by
setting the voltage on the CTL pin of the unused amplifier to 1V or less, it can be put into Power Save Mode.
In Power Save Mode, the circuit current for the IC is
cut by 40%, and the output is muted.
VCA
IN OUT
Control voltage
Fig. 2
CTL Voltage Status
2V ~ 5V Variable gain
1V or less Power save
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Multimedia ICs BA7655A / BA7655AF
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Electrical characteristic curves
1M 10M 100M
10.0
8.0
6.0
4.0
2.0
0.0
100K
– 2.0
– 4.0
– 6.0
– 10.0
– 8.0
CONTROL VOLTAGE = 5V
CONTROL VOLTAGE
=
3V
CONTROL VOLTAGE
=
2V
VOLTAGE GAIN : VG (dB)
VCC = 5V
V
IN = 0.5VP-P
FREQUENCY : ∆f (Hz)
Fig. 3 Voltage gain vs.
frequency
7
6.5
6
5.5
5
0 255075100
– 25– 50
Max. VOLTAGE GAIN (dB)
AMBIENT TEMPERATURE : Ta (°C)
V
CC = 5V
Fig. 4 Maximum voltage gain vs.
ambient temperature
1
0.5
0
0 255075100
– 0.5
– 1
– 50 – 25
Typ. VOLTAGE GAIN (dB)
AMBIENT TEMPERATURE : Ta (°C)
V
CC = 5V
Fig. 5 Voltage gain vs.
temperature
0 255075100
– 5
– 5.5
– 6
– 6.5
–7
– 50 – 25
Min. VOLTAGE GAIN (dB)
AMBIENT TEMPERATURE : Ta (°C)
V
CC = 5V
Fig. 6 Minimum voltage gain vs.
temperature
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External dimensions (Units: mm)
BA7655A BA7655AF
DIP8 SOP8
0.5 ± 0.1
3.2 ± 0.2 3.4 ± 0.3
85
14
9.3
± 0.3
6.5 ± 0.3
0.3
±
0.1
0.51Min.
2.54
0° ~ 15°
7.62
0.4 ± 0.11.27
0.15
0.3Min.
0.15 ± 0.1
0.11
6.2 ± 0.3
4.4 ± 0.2
5.0 ± 0.2
85
41
1.5 ± 0.1
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