MAX463 Maxim, MAX463 Datasheet - Page 15

• Manufacturer Part Number: MAX463
• Description: Two-Channel / Triple/Quad RGB Video Switches and Buffers
• Manufacturer: Maxim

Higher-order RGB video multiplexers can be realized
by paralleling several MAX463/MAX464s. Connect LE
to V+ and use C
one in use. Since the disabled output resistance of the
MAX463/MAX464 is 250kΩ, several devices may be
paralleled to form larger RGB video multiplexer arrays
without signal degradation. Connect series resistors at
each amplifier's output to isolate the disabled output
capacitance of each paralleled device, and use a
MAX469 or MAX470 to drive the output coaxial cables
(see Figure 7).
__________Applications Information
_____________________________________________Pin Configurations (continued)
IN1A
IN2A
IN3A
IN0B
IN1B
IN2B
IN3B
GND
GND
GND
GND
GND
V-
V-
10
11
12
13
14
1
2
3
4
5
6
7
8
9
—
S
–
______________________________________________________________________________________
and E
DIP/SO
MAX464
MAX466
Higher-Order RGB + Sync
—
N
–
to disable all devices but the
Video Multiplexing
28
27
26
25
24
23
22
21
20
19
18
17
16
15
IN0A
LE
EN
A0
CS
V-
OUT0
V-
OUT1
GND
V+
OUT2
V+
OUT3
RGB Video Switches and Buffers
GND
GND
GND
IN0
IN1
IN2
V-
V-
1
2
3
4
5
6
7
8
Two-Channel, Triple/Quad
TOP VIEW
TRIPLE (RGB)
BUFFERS
MAX467
MAX469
DIP/SO
Figure 8 shows a 1-of-4 RGB + sync video mux/amp
circuit. The 1kΩ disabled output resistance limits the
number of paralleled MAX465/MAX466s to no more
than two. The amplifier outputs are connected after a
22Ω isolation resistor and ahead of a 50Ω back-termi-
nation resistor, which isolates the active amplifier out-
put from the capacitive load (5pF typ) presented by the
inactive output of the second MAX466. Impedance
mismatching is minimal, and the signal gain at the
cable end is near 1. This minimizes ringing in the out-
put signals. For multiplexing more than two devices,
see the section Higher Order RGB + Sync Video
Multiplexing, above.
16
15
14
13
12
11
10
9
OUT0
GND
OUT1
V-
V-
OUT2
V+
GND
1-of-4 RGB + Sync Signal Inputs
Paralleling MAX466s to Switch
GND
GND
IN0
IN1
IN2
IN3
V-
V-
1
2
3
4
5
6
7
8
BUFFERS
MAX468
MAX470
QUAD
DIP/SO
16
15
14
13
12
11
10
9
OUT0
GND
OUT1
V-
V-
OUT2
V+
OUT3
15