Propagation delay vs Fracuency

[mayo123]

what is propagation delay

How I can know what are the max Frecuency of operation of a specific family of ICs, according it propagation delay ?
For example: What is the max frec for 74AHCT family, with a 4 ns propagation delay??

Thanks and Regards

 

[Kral]

mayo123,
Define t0 as prop delay going from 1 to 0
Define t1 as prop delay going from 0 to 1
Define t as t0 + t1
The f max must be < 1/t. If f is just a "smidge" below fmax, then you will get slivers of positive going pulses and negative going pulse on the output (assuming the device is a gate). If the device is a flip-flop or other latching type device, then you must also observe setup and hold times on the data inputs. In this case fmax will be less than the value described above.
Regards,
Kral

 

[mayo123]

I understand, Good reply

Thanks, so much.