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Design >> RF Design >> how to measure Q of an inductor in cadence?
https://designers-guide.org/forum/YaBB.pl?num=1205913679

Message started by mike_ok on Mar 19^th, 2008, 1:01am

Title: how to measure Q of an inductor in cadence?
Post by mike_ok on Mar 19^th, 2008, 1:01am

Hi, everyone!
:)
this is my first time to start new topic and i hope that some will help me.
my questions is that in cadence evironment, how to measure the qulity of inductors and its inductance.
as is well know that the expession"Q=[Im(1/Y11)]/[Re(1/Y11)]" and "L=[im(1/Y11)]/[2*pi*freq]" in ADS environment can solve my questions, but in cadence,i don't know how to write the above exprssion, because i cannot find the term of Y11.
your help will be aprreciated!
thanks!

Title: Re: how to measure Q of an inductor in cadence?
Post by pancho_hideboo on Mar 19^th, 2008, 1:54am

See http://www.designers-guide.org/Forum/YaBB.pl?num=1196459940

Title: Re: how to measure Q of an inductor in cadence?
Post by Frank Wiedmann on Mar 19^th, 2008, 3:22am

You should also be aware of the fact that there exist different definitions for the quality factor of an inductor. Depending on your application, some of them may be more useful for you than others. Please see http://www.simics.tec.ufl.edu/papers/00705364.pdf for details.

Title: Re: how to measure Q of an inductor in cadence?
Post by mike_ok on Mar 19^th, 2008, 5:08am

thank you for your replies!
now i still not know the details on how to implemet the term"y11", in my CIW, it says "y11,an unbound varication"
or some one give me more details on mearsure the Q and L?
Thanks a lot ,my dear friends!

Title: Re: how to measure Q of an inductor in cadence?
Post by ACWWong on Mar 19^th, 2008, 6:13am

after you have run an sp analysis y11 is available as:

yp(1 1 ?result "sp")

you can easily use the calculator to access these, more details will be in the cadence documentation.

also note as shown in the example given by pancho_hideboo, you'll need xval() to get the frequency term.

Title: Re: how to measure Q of an inductor in cadence?
Post by RFICDUDE on Mar 19^th, 2008, 4:20pm

A simple simulation technique is to use a 1A AC current source (DC=0A) across the inductor then you can measure the impedance of the inductor directly as the AC voltage across the inductor.

Z=re(Vac)+j*imag(Vac)

Y=1/Z

I like to look at all of these parameters when evaluating integrated inductors

Rs(f) = re(Vac)

Rp(f)=1/re(1/Vac)

Q(f)=imag(Vac)/re(Vac)

L(f)=imag(Vac)/(2*PI*xval(Vac))

Title: Re: how to measure Q of an inductor in cadence?
Post by mike_ok on Jun 26^th, 2008, 11:37pm

thank you, your methody is great! :)