MAX4357 Maxim, MAX4357 Datasheet - Page 37

• Manufacturer Part Number: MAX4357
• Description: The MAX4357 is a 32 x 16 highly integrated video crosspoint switch matrix with input and output buffers
• Manufacturer: Maxim

Figure 7. 128 x 16 Nonblocking Matrix with Reduced Capacitive
Loading
2. Maintain controlled-impedance traces. Design as
3. Minimize ground current interaction by using a good
In addition to crosstalk, another key issue of concern is
isolation. Isolation is the rejection of undesirable feed-
through from input to output with the output disabled.
The MAX4357 achieves a -110dB isolation at 6MHz by
selecting the pinout configuration such that the inputs
Figure 8. Optimal Isolation Resistor vs. Capacitive Load
INPUTS (96–127)
many of the PC board traces as possible to be 75Ω
transmission lines. This lowers the impedance of the
traces reducing a potential source of crosstalk. More
power dissipates due to the output buffer driving a
lower impedance.
ground plane strategy.
INPUTS (32–63)
INPUTS (64–95)
INPUTS (0–31)
32 x 16 Nonblocking Video Crosspoint Switch
32
IN
32
IN
32
IN
32
IN
30
25
20
15
10
5
0
0
OPTIMAL ISOLATION RESISTANCE
MAX4357
MAX4357
MAX4357
MAX4357
100
______________________________________________________________________________________
vs. CAPACITIVE LOAD
CAPACITIVE LOAD (pF)
OUT
OUT
OUT
OUT
16
16
16
16
200
300
16
IN
16
IN
MAX4357
400
OUT
16
500
OUTPUTS (0–15)
and outputs are on opposite sides of the package.
Coupling through the power supply is a function of the
quality and location of the supply bypassing. Use
appropriate low-impedance components and locate
them as close as possible to the IC. Avoid routing the
inputs near the outputs.
Table 6. Input Selection Programming
(MSB)
B4
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
INPUT ADDRESS BIT
B3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
with I/O Buffers
B2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
B1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
(LSB)
B0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
SELECTED
INPUT
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
0
1
2
3
4
5
6
7
8
9
37