[SOLVED] Measuring the Edge Rate in logic circuits

[ParkerMike]

How do you measure the Edge Rate in logic circuits?
What kind of circuits would you want to measure the Logic Edge rate?

 

[D.A.(Tony)Stewart]

Edge rates are often limited by the source resistance and load capacitance. Thresholds for switching states will change with temperature and there are many other considerations, but prop. Delay is important and rise & fall times are specified with worst case and typical due to these considerations.

Logic is usually single ended. But using comparators with differential inputs allows the user to define switching thresholds. Slow rising edges often have ripple and need Schmitt trigger inputs to "square up" the edges.

There are many methods used to measure rise and fall time, due to many different thresholds used for requirements. 10-90% is common for many signals, as is 30-70% or just the slew rate , when determined by drive current limit and load capacitance.