time step too small in ltspice trouble with dflop instance

[raphael]

Good morning

i’m trying to simulate a simple tristate phase detector under LTSPICE, but i’m getting this error:

time step too small in ltspice

i have tried few things but it doesn’t fix the problem. How could i do please?

Thank you in advance for your help

Raphael

[ELEKPAUL]

Hi Raphael,

can you upload the example?

[raphael]

Hi elekpaul

I have removed the +5V biais voltage and the issue has disappeared. However the tristate doesn’t work. I also added a PSPICE version of it.

Could you look at it please?

Many thanks in advance

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[ELEKPAUL]

are you sure that you have the tri-state LTspice model? the symbol appears to refer to an AND model.
if the logic of the circuit is wrong I’m not surprised that you get a convergence error.

[raphael]

Dear Elekpaul

are you refering to the A3 AND gate in both projects? The purpose of this AND gate is to reset the D flipflop when both of them have their Q output set to 1. And then to prevent from having the state where QB=QH=1. This topology is found in the litterature (projet.asc) and works on ORCAD PSPICE.

[ELEKPAUL]

You’re right, I thought you were referring to the AND gate as tristate. I’ve found in the site this Phase frequency detector by Jacob Baker to which I added a CMOS tri state.hope it’s useful for you. About the configuration with the AND gate can you give me a reference?
By the way, I can’t open the PSpice file, what version is it?

Bye

[Author]

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