74hc221

[david_c_partridge]

Does anyone have this a Multisim component for this beastie or a good suggestion as to what else I can readily use as a pulse stretcher?  Some of my input pulses are too narrow for what's needed, and I need to extend them to say 0.5uS.

Thanks

Dave

[Mark_SAI]

Hello,

I have not been able to find a 74HC221 model, have you considered making your own?

[OStep]

David,

At one point I designed a simple digital one shot (monostable) circuit as part of a larger internal design. Note that it is not retrigerrable.  Find it attached. You can set the pulse width in the "Edit Model" dialog in the component's properties.

I hope that helps.

Regards,

[david_c_partridge]

onshot.ms10 is an interesting starting point for a monostable.   I have worked round this for now with a differentiator and diode clamp as a leading edge detector, which is what I actually needed.  The only problem with that is the pullup resistor on the comparator has to be relatively low and therefore the current budget is a bit too high for my comfort in this case.

Ah well, you can't win 'em all.

Cheers

Dave

[Mark_SAI]

Dave,

Did you find a satisfactory solution to your monostable needs in the end?

[david_c_partridge]

No, but the differentiator is doing the job well, and has the advantage it takes very little board space.

We can certainly close this thread off if wished.