Termination example

The maximum track length without termination is given by:

 

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That is, the signal propagation delay from the ASIC to the Mictor connector must be less than one fifth of the signal rise time. This calculation allows for the delay of the Mictor connector and the delay of the track from the Mictor to the input buffers on the probe.

For a case where the signal rise time (Tr) is 1ns (1000ps) and the propagation delay of the trace (Tpdt) is 160ps per inch (typical for a PCB made with FR4 laminate), L must be less than 1000/(5 * 160). That is, L must be less than 1.25 inches. If the PCB trace length from the ASIC to the Mictor connector is greater than 1.25 inches, you must use termination.

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