PCB design method to ensure signal integrity
By summarizing the factors that affect signal integrity, the signal integrity is better ensured in the PCB design process and can be considered from the following aspects.
(1) Circuit design considerations. Including controlling the number of synchronous switching outputs, controlling the maximum edge rate (dI/dt and dV/dt) of each cell to obtain the lowest and acceptable edge rate; selecting differential signals for high output functional blocks (eg, clock drivers); on the transmission line The upper end connects passive components (such as resistors, capacitors, etc.) to achieve impedance matching between the transmission line and the load.
(2) Minimize the length of the parallel wiring.
(3) Keep components away from I/O interconnection interfaces and other areas that are susceptible to interference and coupling, and minimize the spacing between components.
(4) Shorten the distance between the signal traces and the reference plane.
(5) Reduce the trace impedance and signal drive level.
(6) Terminal matching. Terminal matching circuits or matching components can be added.
(7) Avoid routing parallel to each other to provide sufficient trace spacing between traces and reduce inductive coupling.