3-Channel, Video Filter

SGM9132

Driver for HD (1080p)

8

SG Micro Corp

www.sg-micro.com

APPLICATION INFORMATION

Output Considerations

The selection of the coupling capacitor is a function of the

subsequent circuit input impedance and the leakage current of

the input being driven. In order to obtain the highest quality

output video signal the series termination resistor must be

placed as close to the device output pin as possible. This

greatly reduces the parasitic capacitance and inductance effect

on the SGM9132 output driver. Recommended distance from

device pin to series termination resistor should be no greater

than 0.1 inches.

0.1

75Ω series termination resistor

Figure 4. Distance from Device Pin to Series Termination

Resistor

Thermal Considerations

Since the interior of systems such as set-top boxes, TVs and

DVD players are at +70

℃, consideration must be given to

providing an adequate heat sink for the device package for

maximum heat dissipation. When designing a system board,

determine how much power each device dissipates. Ensure that

devices of high power are not placed in the same location, such

as directly above (top plane) or below (bottom plane) each other

on the PCB.

Layout Considerations

General layout and supply bypassing play a major role in

high-frequency performance and thermal characteristics. We

offer a demonstration board to guide layout and aid device

evaluation. The demo board is a four-layer board with full power

and ground planes. Following this layout configuration provides

optimum performance and thermal characteristics for the device.

For the best results, follow the steps and recommended routing

rules listed below.

Recommended Routing/Layout Rules



Do not run analog and digital signals in parallel.



Use separate analog and digital power planes to supply

power.



Do not run traces on top of the ground plane.



Run no traces over ground/power splits.



Avoid routing at 90-degree angles.



Minimize clock and video data trace length differences.



Include 0.01μF and 0.1μF ceramic power supply bypass

capacitors.



Place the 0.1μF capacitor within 0.1 inches of the device

power pin.



Place the 0.01μF capacitor within 0.75 inches of the device

power pin.



For multi-layer boards, use a large ground plane to help

dissipate heat.



For two-layer boards, use a ground plane that extends

beyond the device body at least 0.5 inches on all sides. Include

a metal paddle under the device on the top layer.



Minimize all trace lengths to reduce series inductance.



Place a 75Ω series resistor within 0.5 inches of the output pin

to isolate the output driver from board parasitics.

PCB Thermal Layout Considerations



Understand the system power requirements and environmental

conditions.



Maximize thermal performance of the PCB.



Consider using 70μm of copper for high-power designs.



Make the PCB as thin as possible by reducing FR4 thickness.



Use vias in the power pad to tie adjacent layers together.



Remember that baseline temperature is a function of board

area, not copper thickness.



Consider modeling techniques a first-order approximation.