1
Multimedia ICs
Video signal switcher, 1
3-channel
with clamped-input
BA7653AF
The BA7653AF is a video-signal switching IC that contains a three-channel clamped-input multiplexer. The inputs
are sync-tip clamped (synchronous edge of the video input signals are aligned to the same voltage), and as the input
impedance is extremely large, it is possible to use a small value for the clamp capacitor (the recommended capacitor
is 0.01
F (FZ) ceramic).
Applications
Video cassette recorders, television and camcorders
Features
1) Small clamp capacitors can be used (ceramic,
3000pF (Min.), 0.01
F (FS) (recommended)).
2) Low supply voltage operation possible. Supply volt-
age range is 3.7V to 7.7V.
3) Superimposition used for fast switching speed with
low switching noise (70nsec. Typ.).
4) Low power consumption (when V
CC
= 5V, 25mW
Typ.).
5) Wide dynamic range (3.1V
P-P
Typ. for V
CC
= 5V).
6) Excellent frequency characteristics (10MHz, 0dB
Typ.).
7) Low interchannel crosstalk ( 70dB Typ.).
8) Voltage can be applied to the control pins even
when V
CC
is not applied.
Absolute maximum ratings (Ta = 25C)
Parameter
Symbol
Limits
Unit
V
CC
9
V
mW
Topr
C
Tstg
C
500
Pd
25 ~ + 75
55 ~ + 125
Applied voltage
Power dissipation
Operating temperature
Storage temperature
When mounted on a 50mm
50mm board, reduced by 5mW for each increase in Ta of 1
C over 25
C.
Recommended operating conditions (Ta = 25C)
Parameter
Symbol
Limits
Unit
V
CC
V
4.0 ~ 7.0
Power supply voltage
2
Multimedia ICs
BA7653AF
Electrical characteristics (unless otherwise noted, Ta = 25C and V
CC
= 5.0V)
Parameter
Symbol
Unit
Conditions
Min.
Typ.
Max.
V
CC
3.7
--
--
--
7.7
V
I
CC
2.7
5.0
8.2
mA
V
om
2.6
3.1
--
V
P-P
G
V
0.5
0
dB
C
ta
70
dB
G
f
3.0
0
dB
V
TH L
--
--
1.0
V
V
TH H
2.5
--
--
45
20 (V)
V
CC
V
F
V
TH
=
--
--
f = 1kHz, THD = 1.0%
f = 1MHz, V
IN
= 1.0V
P-P
f = 4.43MHz, V
IN
= 1.0V
P-P
f = 10MHz / 1MHz, V
IN
= 1.0V
P-P
V
CC
CTL Threshold Level
0.5
1.0
Operating voltage
Supply current
Maximum output level
Voltage gain
Interchannel crosstalk
Frequency characteristic
CTL switching voltage
Guaranteed design parameters (unless otherwise noted, Ta = 25C and V
CC
= 5.0V)
Parameter
Symbol
Unit
Conditions
Min.
DG
--
0
0.5
%
DP
--
0.5
1.0
deg
Typ.
Max.
Differential gain
Differential phase
V
IN
= 1.0V
P-P
, standard staircase signal
V
IN
= 1.0V
P-P
, standard staircase signal
Pin descriptions
1
IN1
2
CTLa
3
IN2
4
CTLb
5
IN3
6
V
CC
7
OUT
8
GND
Pin No.
Pin name
Input 1
Control input a
Input 2
Control input b
Input 3
Supply voltage
Output
GND
Function
Control pin truth table
CTLa
CTLb
OUT
L
L
IN1
H
L
IN2
L
H
IN3
H
H
IN3
Block diagram
1
2
3
4
8
7
6
5
IN1
CTLa
IN2
CTLb
GND
OUT
IN3
Logic
V
CC
3
Multimedia ICs
BA7653AF
Input / output circuits
1
IN 1
1.65V
2
CTLa
--
--
3
IN 2
1.65V
4
CTLb
--
--
50
A
100
IN1
V
CC
V
CC
V
CC
V
CC
2.3V
1.9V
50k
CTLa
50
A
100
2.3V
1.9V
50k
CTLb
50
A
Pin No.
IN2
Pin name
DC voltage
(V
CC
= 5V)
Input / output
impedance
Equivalent circuit
10M
or more
10M
or more
4
Multimedia ICs
BA7653AF
50
A
100
V
CC
V
CC
V
CC
V
CC
OUT
1mA
GND
5
IN 3
1.65V
6
V
CC
5.0V
--
7
OUT
0.95V
8
GND
0V
--
Pin No.
IN3
Pin name
DC voltage
(V
CC
= 5V)
Input / output
impedance
Equivalent circuit
10M
or more
26
5
Multimedia ICs
BA7653AF
Application examples
1
2
3
4
8
7
6
5
IN1
CTLa
IN2
CTLb
GND
OUT
V
CC
IN3
Logic
Logic
Logic
V
CC
C. Video In
C. Video In
C. Video In
C. Video Out
0.01
0.01
0.01
47
0.1
+
When superimposition is used
1
2
3
4
8
7
6
5
IN1
CTLa
IN2
CTLb
GND
OUT
IN3
Logic
Logic
Logic
47
0.1
V
CC
V
CC
DC1.7V or more
DC1.7V or more
C. Video or DC Out
C. Video In
0.01
Fig. 1
+
Operation notes
(1) To ensure stable clamp operation, the output
impedance of the previous stage connected to the
inputs should be 1k
or lower.
(2) If large input clamp capacitors are used, the time
constant of the circuit will mean that some time will be
required until stable operation after power is applied.
The value for the input clamp capacitors is 0.1
F Max.
(0.01
F (FZ) ceramic capacitor recommended).
(3) The BA7653AF is a three-channel multiplexer, but
two-channel operation is also possible. In this case, if
the unused input is left open it will oscillate, but this will
not effect the other inputs and cause problems. If this is
a concern, ground the unused input via a capacitor, or
connect it directly to V
CC
.
(4) If control inputs are left open they will be unstable,
set to H or L.
(5) When using superimposition, the DC voltage direct-
ly applied to the inputs should be at least 1.7V.
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