The Designer's Guide Community
Forum
Welcome, Guest. Please Login or Register. Please follow the Forum guidelines.
Mar 28th, 2024, 10:18am
Pages: 1
Send Topic Print
measures for substrate noise reduction (Read 2426 times)
ywguo
Community Fellow
*****
Offline



Posts: 943
Shanghai, PRC
measures for substrate noise reduction
Apr 11th, 2004, 7:51am
 
Hello,

As well known, substrate noise is a very severe problem in mixed signal circuit design.

Basically, the digital supply and analog supply are seperated on chip. Some papers has presented that guard ring is not effective for low-ohmic substrate. Somebody recommends that analog ground should not connect to substrate because the low-ohmic substrate is polluted by digital circuits.

But I am confused by a practical configuration. It is shown in the following.
vdda     3.3V DAC supply
vssa     clean vssa (not connected to substrate), connect to board analog ground
gnda    Ground input (connected to substrate),  connect to vssa if using high-ohmic substrate, connect to digital gnd! if using low-ohmic substrate.
gnd!     substrate ground, keep minimal resistance to gnd! bondpad
vdd!     digital supply

Who could explain the configuratoin for me? Thanks very much in advance.


Best Regards,

Yawei Guo
Back to top
 
 
View Profile   IP Logged
Pages: 1
Send Topic Print
Copyright 2002-2024 Designer’s Guide Consulting, Inc. Designer’s Guide® is a registered trademark of Designer’s Guide Consulting, Inc. All rights reserved. Send comments or questions to editor@designers-guide.org. Consider submitting a paper or model.