MAX4356ECD+T Maxim Integrated Products, MAX4356ECD+T Datasheet - Page 37

• Manufacturer Part Number: MAX4356ECD+T
• Description: IC VIDEO CROSSPOINT SWIT 128TQFP
• Manufacturer: Maxim Integrated Products

Specifications of MAX4356ECD+T

• Function: Video Crosspoint Switch
• Circuit: 1 x 16:16
• Voltage Supply Source: Single, Dual Supply
• Voltage - Supply, Single/dual (±): 5V, ± 3 V ~ 5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 128-TQFP, 128-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

This technique for inserting OSD display information is
an improvement over the way it has traditionally been
done. Other OSD techniques require an external fast
mux and a buffer for each output.
Crosstalk Signal and Board Routing Issues
Improper signal routing causes performance problems
such as crosstalk. The MAX4356 has a typical crosstalk
rejection of -62dB at 6MHz. A bad PC board layout
degrades the crosstalk rejection by 20dB or more. To
achieve the best crosstalk performance:
1) Place ground isolation between long critical sig-
2) Maintain controlled-impedance traces. Design as
3) Minimize ground-current interaction by using a
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 MAX4356 acheives a -110dB isolation at 6MHz by
selecting the pinout configuration such that the inputs
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
Figure 8. Optimal Isolation Resistor vs. Capacitive Load
with On-Screen Display Insertion and I/O Buffers
nal PC board trace runs. These traces act as a
shield to potential interfering signals. Crosstalk can
be degraded by parallel traces as well as directly
above and below on adjoining PC board layers.
many of the PC board traces as possible to be 75
transmission lines. This lowers the impedance of the
traces, reducing a potential source of crosstalk.
More power will be dissipated due to the output
buffer driving a lower impedance.
good ground plane strategy.
16 x 16 Nonblocking Video Crosspoint Switch
30
25
20
15
10
5
0
0
OPTIMAL ISOLATION RESISTANCE
100
______________________________________________________________________________________
vs. CAPACITIVE LOAD
CAPACITIVE LOAD (pF)
200
300
400
500
appropriate low-impedance components and locate
them as close as possible to the IC. Avoid routing the
inputs near the outputs.
The MAX4356 operates from a single +5V or dual ±3V
to ±5V supplies. For single-supply operation, connect
all V
pins with a 0.1µF capacitor to ground. For dual-supply
systems, bypass all supply pins to ground with 0.1µF
capacitors.
The MAX4356 has been designed to operate with split
supplies down to ±3V or a single supply of +5V.
Operating at the minimum supply voltages reduces the
power dissipation by as much 40% to 50%. At ±5V, the
MAX4356 consumes 195mW (0.76mW/point).
The MAX4356 output buffers can be programmed to
either A
typically used when driving a short-length (less than
3cm), high-impedance "local" PC board trace. To drive
a cable or a 75
gain of the output buffer to +2V/V and place a 75
resistor in series with the output. The series termination
resistor and the 75
divider that divides the video signal in half. Set the gain
to +2V/V to transmit a standard 1V video signal down a
Figure 9. Improved Implementation of On-Screen Display
SYNC15
SYNC0
SYNC1
CAMERAS
MEMORY
EE
V
pins to ground and bypass all power-supply
Driving a PC Board Interconnect or a
= +1V/V or +2V/V. The +1V/V configuration is
OSD
OSD
OSD
COMPUTER CONTROL
OSDFILL15
OSDKEY15
OSDFILL0
OSDFILL1
OSDKEY0
OSDKEY1
transmission line trace program the
IN15
Cable (A
IN0
IN1
load impedance act as a voltage-
Power-Supply Bypassing
Power in Large Systems
MAX4356
V
= +1V/V or +2V/V)
OUT0
OUT1
OUT15
SYNC0
SYNC15
SYNC1
MONITOR 15
MONITOR 1
MONITOR 0
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