Trouble with Cadence ADE simulation step size

[krivan]

cadence transient liberal

Hi,

I'm trying to simulate a complex circuit with an oscillator in it. I want to do transient simulation with a time step of, let's say, 1ns, 1ms, 10ms,.... I put the number I want to use into the bracket of

ADE -> Choose Analysis... -> tran -> Options -> time step parameters

So, it does no matter what I put there, the simulator doesn't care and always calculates with a ps time frame but sometimes it is decreased to fs.
This is quite annyoing because the complete simulation time is 15s...

What should I set to get much larger time steps?

 

[kDaniu]

transient cadence ade

I also do not understand clearly this one but spectre som adaptive choosing the time step (even if you set it handly)
and time step depend from the processes in circuite ..
probably you enable the "Transient Noise" advantages etc, your time step depend from that and that is why you get a step in ps sometime...

 

[Teddy]

cadence time step transient

In Spectre (ADE) go to transient simulation option and there will be 2 time step parameters.
step - sets in fact only initial step used for simulation. Then depending on the sim method the time step is adjuste during simulation.

maxstep - set maximum allowed step for the sim. Simulator will still be adjusting the step during sim but the step will never exceed the maxstep value.

 

[krivan]

cadence maximum step size

I set

step: 1ms
max. step: 2ms

but unfortunately the step size stayed in the ps range.

 

[alvays]

ade simulator

krivan
I dont have cadence manual at hand. But I remeber that you can change the really simulation accuracy by simulation->options->analog->volt resol, i resol, relative resol, as well as conservative, moderate, liberal in transient.
But to remeber that, the simulation step affected by the circuit behavior and your accuracy settings.
You said that you have oscillator in your block. it may be too large step to oscillate.

--alvays

 

[jgrant3]

conservative moderate liberal spectre

krivan
I dont have cadence manual at hand. But I remeber that you can change the really simulation accuracy by simulation->options->analog->volt resol, i resol, relative resol, as well as conservative, moderate, liberal in transient.
But to remeber that, the simulation step affected by the circuit behavior and your accuracy settings.
You said that you have oscillator in your block. it may be too large step to oscillate.

--alvays

I don't think he has a problem with getting the oscillator to actually oscillate. The issue is speeding up the simulation, i.e. setting a larger step size between simulation points.

Does anyone else have any other ideas on how to speed up simulations in Cadence?