On die termination VS on board termination

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kintaro

Joined Jun 1, 2022
16
I made transient simulations between on die termination (termination is after the wire bond) VS on board termination (termination is before the wire bond).
The result shows that the termination after the wire bond performs better with less ringing.

Does anyone know how to explain this phenomenon in simple words? I hope we are not getting into mathematical details. I prefer a conceptual explanation.
Thank you!!!

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Ya’akov

Joined Jan 27, 2019
6,856
Before avoids the (equivalent) series inductance and shunt capacitance of the parasitics. These form a resonant circuit at some frequency, so it rings causing the over- and undershoot.

It should be a surprise that with fewer sources of capacitive and inductive reactance you would get less mismatch and so less ringing.

(This is my understanding of the situation, I am very happy for someone else to confirm, modify, or dispose of it.)
 
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