Home > Community > Forums > Custom IC SKILL > Is Cgs= -(Cgg+Cgb+Cgd) or Cgs=-(Cgg+Cgb)?

Email

* Required Fields

Recipients email * (separate multiple addresses with commas)

Your name *

Your email *

Message *

Contact Us

* Required Fields
First Name *

Last Name *

Email *

Company / Institution *

Comments: *

 Is Cgs= -(Cgg+Cgb+Cgd) or Cgs=-(Cgg+Cgb)? 

Last post Mon, May 26 2014 12:15 PM by Alex Liao. 2 replies.
Started by Alex Liao 11 Apr 2014 03:51 PM. Topic has 2 replies and 211 views
Page 1 of 1 (3 items)
Sort Posts:
  • Fri, Apr 11 2014 3:51 PM

    • Alex Liao
    • Top 150 Contributor
    • Joined on Wed, May 22 2013
    • Posts 47
    • Points 775
    Is Cgs= -(Cgg+Cgb+Cgd) or Cgs=-(Cgg+Cgb)? Reply

    Hi,

     I found these two equations in MOS Capacitance Model section from Virtuoso Simulator Components and Device Models Reference.

    In Triode region, the first equations works and the second one works for Saturation region.

    Triode: Cgs= -(Cgg+Cgb+Cgd)

    Saturation: Cgs=-(Cgg+Cgb)

     

     But in my Print DC table, I copied the values of Cgg, Cgb and Cgd. I find the Cgs always has a value very closer to the result got from Triode region equation verification even I am sure it is working in Saturation region.

    Is there anybody who knows why?

     Thanks, 

    • Post Points: 20
  • Fri, May 23 2014 8:13 PM

    • Quek
    • Top 10 Contributor
    • Joined on Wed, Oct 14 2009
    • Singapore, 00-SG
    • Posts 1,082
    • Points 16,475
    Re: Is Cgs= -(Cgg+Cgb+Cgd) or Cgs=-(Cgg+Cgb)? Reply

    Hi Alex

    You might want to post this question in the customIC forum or the designer's guide forum.

    Best regards
    Quek

    • Post Points: 20
  • Mon, May 26 2014 12:15 PM

    • Alex Liao
    • Top 150 Contributor
    • Joined on Wed, May 22 2013
    • Posts 47
    • Points 775
    Re: Is Cgs= -(Cgg+Cgb+Cgd) or Cgs=-(Cgg+Cgb)? Reply

    Hi  Quek,

     

    Thanks a lot!

     

    • Post Points: 5
Page 1 of 1 (3 items)
Sort Posts:
Started by Alex Liao at 11 Apr 2014 03:51 PM. Topic has 2 replies.