Simulation of active inductor on cadence

[acekas]

Hi all,

I am trying to simulate an active inductor on cadence c35 b4. I need to plot the resistance, inductance and q-factor as functions of frequency. Can someone help me out with how to go about this?

Thanks in advance!
Kas

 

[acekas]

Ok, this is what I am doing. I am connecting one end of the active inductor to the port, and the other end is grounded. Next, I am doing a S-parameter analysis, and from that, I am plotting the real part of Z to get the resistance, and the imaginary part of Z to get the inductance.

Is this method right, or I am completely off-track?

Please reply soon! Thanks!

 

[LvW]

................
I am plotting the real part of Z to get the resistance, and the imaginary part of Z to get the inductance.

Is this method right, or I am completely off-track?

Of course, when you have the complex impedance Z as a function of frequency, then you can split it into a real part R and the imaginary part ωL. Dont forget to divide by ω before interpreting the result as inductance L.

 

[acekas]

Thanks LvW!

But can someone also point out if the method I am using is correct? As in doing the S-parameter analysis, and then using the Z paramater. Or is there some other way?

 

[totowo]

Thanks LvW!

But can someone also point out if the method I am using is correct? As in doing the S-parameter analysis, and then using the Z paramater. Or is there some other way?

It's ok, but since you connect one terminal of inductor to ground, so it's just a single-ended Q

if you use it as a differential Q or some else
(none of terminal is connected to ground)
the former method may be not correct. you should connect the negative of the port to the 2nd terminal of inductor without connect to ground

if you illustrate the equivalent circirt of inductor you will find there DO be some difference.

 

[acekas]

Once again, thanks for all the help. There's something else I'd like to know.

To find the inductance value, I need to divide the imaginary part of the Z-parameter by frequency, right? So how do I type that in the calculator?

Hoping for a fast reply. Thanks!

 

[del-sig]

Hi

I'm simulating active inductor using spectre in cadence 180nm. I would like to get Q and transfer function from inductor. I wanna know how to get those values from spectre. If you have any idea about this, please share your views.

 

[acekas]

Hi

I'm simulating active inductor using spectre in cadence 180nm. I would like to get Q and transfer function from inductor. I wanna know how to get those values from spectre. If you have any idea about this, please share your views.

Hey,

I am not too sure there is any way you can determine the transfer function of the inductor from cadence. For the transfer function, you will have to find the equivalent circuit of the active inductor. You can get that by doing a small signal analysis of the active inductor circuit, you will get the transfer function. (Read a few papers on active inductors; it will show you how to get that!)

For the quality factor, you will have to run an S-paramter simulation on your circuit (I hope you know how to do that. If not, ask any of your seniors working in your lab, they will help!) Once you've run the simulation, from the "Tools" option of the Analog Design Environment (ADE) window, open the calculator. There, you type

imag(ZP(1 1))/real(ZP(1 1))

where imag(ZP(1 1)) gives you the imaginary part of Z11, and real(ZP(1 1)) gives you the real part. This should give you the quality factor.

I don't know if you wanted to know how to run the simulation too. If so, tell me, I might be able to help (I might be a little late in replying though!).

Hope this helps!
Kas

 

[del-sig]

thanks for ur reply. i read few papers regarding transfer function calculation.. btw, i wanna get quality factor from spectre simulation..like freq vs magnitude relationship.. do u know how to get Q from the graph...

 

[acekas]

thanks for ur reply. i read few papers regarding transfer function calculation.. btw, i wanna get quality factor from spectre simulation..like freq vs magnitude relationship.. do u know how to get Q from the graph...

the expression i sent you calculates the magnitude of quality factor wrt freq. you have to run an s-parameter simulation. do u know how to do that? it would be best if someone can show you how to do that... ask for help from some of your seniors. select sp in the choose analysis window, and click on freq, and specify the start and stop freq, over which you want to run your simulation.

tell me if this helps!
Kas

 

[del-sig]

hi. I am trying to do s parameter analysis.. here no one is working on this topic.. so i'm searcing from google and eda board.. do u know how to do sp analysis in spectre..

 

[sharabi.salah]

HI..

To do an Sparameter simulation in cadence check the folowing document

**broken link removed**

Good Luck