FMS6501 Datasheet, PDF (11/16 Pages) Fairchild Semiconductor – 12 Input 9 Output Video Switch Matrix with Input Clamp, Input Bias Circuitry, and Output Drivers

Layout Considerations
General layout and supply bypassing play major roles in high
frequency performance and thermal characteristics. Fairchild
offers a demonstration board, FMS6501DEMO, to use as a
guide for layout and to aid in device testing and characterization.
The FMS6501DEMO is a 4-layer board with a full power and
ground plane. For optimum results, follow the steps below as a
basis for high frequency layout:
• Include 10µF and 0.1µF bypass capacitors
• Place the 10µF capacitor within 0.75 inches of the power pin
• Place the 0.1µF capacitor within 0.1 inches of the power pin
• Connect all external ground pins as tightly as possible, pref-
erably with a large ground plane under the package.
• Layout channel connections to reduce mutual trace induc-
tance
• Minimize all trace lengths to reduce series inductances. If
routing across a board, place device such that longer traces
are at the inputs rather than the outputs.
If using multiple, low impedance DC coupled outputs, special
layout techniques may be employed to help dissipate heat.
If a multilayer board is used, a large ground plane directly under
the device will help reduce package case temperature.
For dual layer boards, an extended plane can be used.
Worse case additional die power due to DC loading can be esti-
mated at (V_cc2/4R_load) per output channel. This assumes a con-
stant DC output voltage of V_cc/2. For 5V V_cc with a dual DC
video load, add 25/(4*75) = 83mW, per channel.
Applications for the FMS6501 Video Switch
Matrix
The increased demand for consumer multimedia systems has
created a large challenge for system designers to provide cost-
effective solutions to capitalize on the growth potential in graph-
ics display technologies. These applications will require cost
effective video switching and filtering solutions to deploy high-
quality display technologies rapidly and effectively to the target
audience. Areas of specific interest include HDTV, Media Cen-
ters, and Automotive Infotainment(includes navigation, in cabin
entertainment, and back up camera). In all cases, the advan-
tages the integrated video switch matrix provides are high qual-
ity video switching specific to the application as well as video
input clamps and on chip low impedance output cable drivers
with switchable gain.
Generally the largest application for a video switch is for the
front end of an HDTV. This is used to take multiple inputs and
route them to their appropriate signal paths (main picture and
picture in picture - PiP). These are normally routed into ADCs
that are followed by decoders. There are many different technol-
ogies for HDTV including: LCD,Plasma, and CRT that have sim-
ilar analog switching circuitry.
An example of a potential HDTV application is shown in figure 7
below. This system combines a video switch matrix and 2 -
three channel switchable anti-aliasing filters. This is done as
there are two 3-channel signal paths in the system - One is for
the main picture, and the other is the path for “Picture in Pic-
ture”.
VIPDEMO^TM Control Software
The FMS6501 is configured via an I²C compatible digital inter-
face. In order to facilitate ease of demonstration, Fairchild Semi-
conductor had developed the VIPDEMO^TM GUI based control
software to write to the FMS6501 register map. This software is
included when ordering an FMS6501DEMO kit. Also included is
a Parallel port I²C adapter and an interface cable to connect to
the demo board. Besides using the full FMS6501 interface, the
VIPDEMO^TM can also be used to control single register read
and writes for I²C.
Figures 8 and 9 below show the control panel for the VIPDE-
MO^TM control software and the FMS6501 device evaluation
board.
FMS6501 Rev. 1A
11
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