Constant Phase Element

What's "cadence simulation"? There's no tool called cadence (that's the company name). We have numerous simulators:

• spectre
• AMS Designer
• PSPICE
• Ultrasim

or you could be talking about a non-Cadence simulator in a Cadence simulation environment (e.g. Virtuoso Analog Design Environment).

What is Z? Is it an impedance? 

In general what you're asking for sounds like a non-physical behaviour that would be risky in a time domain simulation but in frequency domain it might be possible - however, without having more detail about the tools and versions you're trying to use (and the problem you're trying to solve) I'm not going to guess. This is why we ask for this information in the forum guidelines.

Regards,

Andrew.

Sorry about the missing details.

- I need this for Spectre simulation , but if it can be done in any other tool it will be fine also.

- Yes, Z is the impedance, it is like non-ideal capacitor. It is to describe a physical phenomenon though.

- In fact I want to run transient simulation.

Thanks,

Ahmed 

Hi Ahmed,

Actually it isn't physical. It's a model over a narrow frequency range. It can't really have that behaviour over all frequencies.

Because of that you can end up with a non-causal model.

If you look at "spectre -h bsource" you'll see that this has the ability to describe such relationships using the $freq keyword. However, this for frequency-domain analyses only. There's also "spectre -h fracpole" which is a way of doing (I think) what you want.

Both of these would require you to create a subckt model and then reference that in ADE (if using ADE).

You might be best advise to go to customer support if you can't work out the details from the pointers I've provided above.

Regards,

Andrew.

Hi Andrew,Thanks very much for your fast reply. I see ... this seems to be very useful, I ll give it a try and see what will happen.

Ahmed