In this tutorial we are going to lean about WHAT IS RC TERMINATION IN PCB DESIGN ?
AC termination is recommended most for clock applications. An example of AC
termination is when a 75? impedance is coupled with a 100pF capacitor. That allow for leakage in input impedance of the receiver, A resistor is selected to be larger than the trace impedance. That allow for rapid transition of the clock edge, the capacitor value is selected at 120pF. The higher capacitor value allows for heavier current levels to pass. However, higher capacitive values increases power dissipation.
Capacitor values less than 50pF diminish the effectiveness of termination.
This method terminates the signal transition & therefore should be calculated based on the edge rate. This method’s disadvantage is that 2 components are needed for each line. Termination packs are sometimes used to reduce component count. Be aware that signal coupling can occur between signals in the termination pack. An RC circuit arranged in series to a voltage source, usually ground, makes a dynamic termination. The result of this is the cut off of glitches & overshoot.