Intel 21143 Suggestions for Routing, Engineering Electromagnetic Capability, by V. Prasad Kodali

Intel® 21143 PCI/CardBus 10/100Mb/s Ethernet LAN Controller

•Engineering Electromagnetic Capability, by V. Prasad Kodali

6.2.2Suggestions for Routing

For routing information, consider the following suggestions:

•Never route any etch (power or ground) across a partition or void because the signal loses its return-path integrity and contaminates the isolated plane.

•Avoid placing oscillators, phase-locked loops, and other clock-type devices near I/O connectors.

•Route all critical signals (for example; clocks, video output) directly in the etch and avoid, if possible, using vias (signal paths routed between planes in an etch board).

Note: Critical signals should be prioritized from the fastest to the slowest with respect to frequency and rise time. The fastest critical signals should be routed first.

24 Design Guide