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Peaking Coil

Goal of this page - Discuss "Peaking Coils",
Inductors used to speed up logic level timing

From Guy Fedorkow < guy.fedorkow@gmail.com >

Greetings Colleagues,
     There was a question a couple weeks ago about the inductor in CTDL logic... I had an hour last week when I was should have been doing something else, but instead assembled a small Spice simulation of the gate with and without the inductor.


     As guessed, the inductor sharpens the edge that's formed when the transistor turns off and the load resistor is in charge of switching levels.
     I added 100 pF of load... I have no idea what the real loading is, but that seems like a possible value for a long wire and a couple of terminations.
     If someone can stick a probe on a relatively clean logic signal and send me a photo, maybe we can calibrate the model a bit more carefully.
     As usual, my first reaction was "an inductor makes it faster?? Can't be!" But of course that's what it does.

/guy


Updated Sept 6, 2015