SN74AC14: Problem in Altium Pspice simulation

Domenico Carluccio

Part Number: SN74AC14

Hello,

for my simulation I downloaded the SN74AC14 Spice model and used it by Altium.

It has a strange behavior as you can see by the attached images; it seems that the input impedance on the A input is 0.01 ohm, as you can see the current in R4 is 330A (V1 is generating a pulse of amplitude 3.3V.

I noticed that because I tried to put two inverter in series and the output of the second one is always zero.

Could someone help me? Is there something I am doing wrong?

Thanks

Domenico

over 2 years ago

+1 Karan Kotadia over 2 years ago

TI__Genius 16725 points

Hi Domenico,

It looks like there is a typo with the input resistance of the model.

I have fixed the problem. Please let me know if you face any other issues.

8228.SN74AC14.cir 1754.SN74AC14.lib

Regards,

Karan

0 Domenico Carluccio over 2 years ago in reply to Karan Kotadia

Prodigy 10 points

Thank you Karan!

I'm facing now a minor issue: when I use this model in Altium simulator, my transient analysis settings are always overriden, I don't know why, but the time base of the transient analysis is always 5 times the period of the pulse generator I'm using to stimulate the SN74AC14 input. The result is that I can't choose the time base i want to enlarge the plots

This doesn't happen in other simulations, my setting in simulation dashboard are never overidden.

Have you any idea why it is happening?

Thank you in advance for your help

Best regards

Domenico

0 Emrys Maier over 2 years ago in reply to Domenico Carluccio

TI__Guru* 96591 points

Hi Domenico,

Can you share your project file with us so we can take a look?

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SN74AC14: Problem in Altium Pspice simulation