The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl Modeling >> Semiconductor Devices >> drain capacitance calculations https://designers-guide.org/forum/YaBB.pl?num=1195046585 Message started by jefkat on Nov 14th, 2007, 5:23am |
Title: drain capacitance calculations Post by jefkat on Nov 14th, 2007, 5:23am Hi guys, I am trying to calculate the total cap at drain. The spectre output parameters (that you get after the sim) have an element called 'cdd'. According to definition this is dQd/dVd. So the change in drain charge to a change in drain voltage. If the definition is right then 'cdd' must be the total cap at the drain node. However ac sims show that actual cap is somewhat bigger than this 'cdd'. Would anyone please explain where is this comming from? has it to do with mutiterminal cap stuff (guessing)? Thanks :) Shaf |
Title: Re: drain capacitance calculations Post by Geoffrey_Coram on Nov 15th, 2007, 8:40am cdd usually refers only to the channel capacitance, so it excludes overlap and depletion capacitances. |
Title: Re: drain capacitance calculations Post by jefkat on Nov 16th, 2007, 1:02am Thanks much for your reply! |
The Designer's Guide Community Forum » Powered by YaBB 2.2.2! YaBB © 2000-2008. All Rights Reserved. |