Transient simulation accuracy

There are a couple of simulation parameters which are a function of the simulation duration (e.g. maxstep) however, I would be surprised if these had a significant effect.

Trying to guess the problem without seeing anything (you didn't mention which simulator, which version, or indeed much information at all about the simulation setup) is going to be very hard. This is probably best handled by going to customer support.

Kind Regards,

Andrew.

Hello Andrew,

I am using cadence spectre simulator on cadence2012 virtuoso ADE. I have setup a transient analysis and am trying to note down the voltages that I am running through the ADC and the digital codes that my ADC is generating. When I have a longer simulation time (vis 5+ us) with a longer ramp the codes that I am getting are in the steps of 128 (which is loss of 7bits) where as if I am using a smaller simulation time (viz 2us) I am getting codes as expected.

I hope I have been able to convey what I am trying to achieve.

Please let me know of additional information I should give. I am new to the forum and IC design as such.

Thanks

Yaman 

Yaman,

It sounds rather unlikely that the simulator would be making such a huge error unless there was something fundamentally wrong in your simulation setup or more likely in the circuit or test bench itself. Circuit simulators (even when asked to run with very loose tolerances) typically don't make such gross errors. So without seeing your circuit, it's hard to know what the problem is - as I said. I suggest you talk to your supervisor, because clearly something is wrong, and if nobody can see it, nobody will be able to point you in the right direction.

Regards,

Andrew.