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AV9155

AV9155 Recommended Board Layout

This is the recommended layout for the AV9155 to maximize clock performance. Shown are the power and ground connections,

the ground plane, and the input/output traces.

Use of the isolated ground plane and power connection, as shown, will prevent stray high frequency ground and system noise

from propagating through the device. When compared to using the system ground and power planes, this technique will

minimize output clock jitter. The isolated ground plane should be connected to the system ground plane at one point, near the

2.2µF decoupling cap. For lowest jitter performance, this isolated ground plane should be kept away from clock output pins and

traces. Keeping the isolated ground plane area as small as possible will minimize EMI radiation. Use a sufficient gap between the

isolated ground plane and system ground plane to prevent AC coupling. The ferrite bead in the VDD line optional, but will help

reduce EMI.

The traces to distribute the output clocks should be over a system ground or power supply plane. The trace width should be

about two times the thickness of the PC board between the trace and the underlying plane. These guidelines help minimize clock

jitter and EMI radiation. The traces to distribute power should be as wide as possible.