Thursday, February 19, 2015

Changing Digital Cell Macro Parameters in LTspice

How to Change Logic Levels in LTspice

https://groups.yahoo.com/neo/groups/LTspice/conversations/topics/38474
http://www.electronicspoint.com/threads/how-to-change-logic-levels-in-ltspice.119681/

Documented in the builtin help under Special functions..

Vhigh, Vlow, Trise, Tfall, Ref (default 0.5*(Vhigh + Vlow) ) Td (delay) and a few more..

Now, wouldn't it be nice to see what parameters diffschmitt has?
So, despite appearances, the diffschmitt isn't really a comparator - that is, when you specify Vhigh and Vlow, don't expect the output to go HI when V(in+ , in-) > 0. That's right - V(in+, in-) needs to exceed Ref - yuck, I know.. So, to get a comparator function out of this one, you need to specify Ref = 0.

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