The Designer's Guide Community
Forum
Welcome, Guest. Please Login or Register. Please follow the Forum guidelines.
May 24th, 2022, 8:02pm
Pages: 1
Send Topic Print
Capacitive DAC Unit Cell Size in ADC (Read 452 times)
niloun
Community Member
***
Offline



Posts: 51

Capacitive DAC Unit Cell Size in ADC
Apr 27th, 2021, 11:06pm
 
Hi everyone,

When we want to calculate ADCs sampling capacitor size we choose C such that thermal noise level is less (or equal) than quantization noise

KT/C<Δ2/12

Which leads to

C>12KT×22b/VFS2

My question is that if "C" here is the total capacitance of the capacitor array or unit cell capacitor? and why?

For example if in the case of an eight bit ADC we find C>20fF from C>12KT×22b/VFS2
should we divide 20fF by 28 to find the minimum unit cell size or C is the minimum unit cell size itself?
Back to top
 
« Last Edit: Apr 28th, 2021, 2:16pm by niloun »  
View Profile   IP Logged
niloun
Community Member
***
Offline



Posts: 51

Re: Capacitive DAC Unit Cell Size in ADC
Reply #1 - Mar 3rd, 2022, 10:55am
 
Solved.
"C" here is the total capacitance of the capacitor array.

Thanks,
Nilou
Back to top
 
 
View Profile   IP Logged
Pages: 1
Send Topic Print
Copyright 2002-2022 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.