The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Design >> Mixed-Signal Design >> deep nwell isolation effectiveness
https://designers-guide.org/forum/YaBB.pl?num=1376011266

Message started by RobG on Aug 8^th, 2013, 6:21pm

Title: deep nwell isolation effectiveness
Post by RobG on Aug 8^th, 2013, 6:21pm

Hi All,
I have a vague memory of someone (loose-electron?) saying they did some studies on deep Nwell isolation and found that the noise isolation improvements were minimal. Was the issue that you could not contact it at a low enough impedance? Any (decent) papers on the subject?

rg

Title: Re: deep nwell isolation effectiveness
Post by loose-electron on Aug 18^th, 2013, 11:56am

yes - we did some real world studies and the deep well does not help that much in most cases (2-4dB)

(IBM, SiGe processes with deep-n-well 6HP IIRC)

At high frequencies, coupling is going to be by parasitic paths and the deep wells do not make parasitics go away by magic.