When a signal changes layers, place a "transfer via" (a ground via) right next to the signal via. This provides a continuous path for the return current to jump layers along with the signal. 8. Strategic Layer Stack-up
For any clock line or high-speed data bus, use proper termination (like series resistors at the source). This damps the rise times just enough to reduce high-frequency harmonics without ruining the signal's timing. Summary Checklist Never route over a split in the ground plane. When a signal changes layers, place a "transfer
At the foundational level, EMC design begins with a robust understanding of the return current path. In DC circuits, current follows the path of least resistance, but in high-frequency AC circuits, current follows the path of least inductance. This means the return current will naturally attempt to flow directly beneath the signal trace on the reference plane. Basic design dictates that designers must provide a continuous, unbroken ground plane to facilitate this. Cutting or slotting a ground plane forces the return current to take a long detour, creating a large loop area. These loops act as efficient antennas, radiating electromagnetic interference (EMI) and increasing the likelihood of crosstalk between adjacent traces. Strategic Layer Stack-up For any clock line or