The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Design >> Mixed-Signal Design >> comparator offset
https://designers-guide.org/forum/YaBB.pl?num=1199679128

Message started by analog_cha on Jan 6^th, 2008, 8:12pm

Title: comparator offset
Post by analog_cha on Jan 6^th, 2008, 8:12pm

Hi
Can any body suggest me how to measure offset for the clocked comparator??

Thanks.

Title: Re: comparator offset
Post by vivkr on Jan 10^th, 2008, 2:58am

Hi,

There are 2 ways:

1. Lazy and simple way but approximate: If you have atleast 1 preamplifier stage, then you can estimate its offset separately
using Monte Carlo analysis without clocking, and then estimate overall offset.

2. Otherwise, try the following:

Run your circuit in clocked mode as it would normally work.

Sweep the input voltage as a variable in Monte Carlo analysis.

The approximate offset for each Monte Carlo iteration may be estimated by looking at the inputs
between which the comparator output switches from LOW to HIGH.

Generate a histogram of the crossing point for a large number of runs. You will thus get a distribution of the offset.

Note that the above can be easily automated if you define your outputs well as Monte Carlo saves all the relevant outputs
in the mcdata file.

Hope this helps.
Vivek

Title: Re: comparator offset
Post by Frank Wiedmann on Jan 10^th, 2008, 5:16am

See also http://www.designers-guide.org/Analysis/comparator.pdf.