HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
  |  REGISTER  |  LOGIN  |  HELP
Blogs
Blog

Settling Times Affect ADC Accuracy

NO RATINGS
View Comments: Threaded|Newest First|Oldest First
Nancy Golden
User Rank
Platinum
Great Topic!
Nancy Golden   6/19/2012 3:06:22 PM
NO RATINGS

Great article, Jon – thanks so much for sharing on a sometimes overlooked but extremely important part of taking accurate measurements. Settling times should be taken into account and I think how that is best handled depends on the circuitry, what is being measured and what is being used to take the measurements. On test sets we would keep cables as short as possible and in the old days we would simple do that through software by trial and error to come up with a reliable software delay (scary I know!) However, with the systems we were working on we were mostly taking DC measurements that were extremely repeatable so it worked out okay. I really appreciate the variety of solutions you offered – with the complexity of today's designs they offer great solutions and makes me want to go experiment!



Jon Titus
User Rank
Blogger
Re: Great Topic!
Jon Titus   6/19/2012 6:00:13 PM
NO RATINGS
Thanks, Nancy.  Often we overlook details that later cause problems.  I know of several cases in which not accounting for settline time caused erroneous measurements.  Thankfully the people involved discovered the problem.

Nancy Golden
User Rank
Platinum
Re: Great Topic!
Nancy Golden   6/19/2012 6:33:33 PM
NO RATINGS
I think that is where experience comes into play, Jon - and why it is so important for junior engineers to learn from senior engineers. I am forever grateful for the engineers that took the time to teach me real world things that you don't necessarily learn (or remember) from school - including settling times!

Walt
User Rank
Gold
Reference also important
Walt   6/20/2012 1:14:33 PM
NO RATINGS
Yes, this subject becomes even more important when you are sampling from an analog multiplexer.  Then the multiplexer output must settle before the sample is taken, which must also settle. :-)

Another similar important note is at the ADC reference.  Like the input itself, some ADCs draw small surge currents from the reference, so a well thought out capacitance at the reference and a low impedance reference voltage source may reduce complications (and confusion) when figuring out settling time.

Jon Titus
User Rank
Blogger
Re: Reference also important
Jon Titus   6/20/2012 1:30:40 PM
NO RATINGS
Thanks for information about the ADC reference.  I had always thought the current draw was constant.

Partner Zone
More Blogs
Some of our culture's most enduring robots appeared in the 80s. The Aliens series produced another evil android, and we saw light robot fare in the form of Short Circuit. Two of the great robots of all time also showed up: The Terminator and RoboCop.
A soundproofing invention called Acoustiblok recently won a television challenge to silence an air horn with only a fraction of an inch of polymer material.
Robots came into their own in the 1970s. Gone were the low-budget black-and-white B movies. Now robots roamed in full-color feature films with A-list actors.
Major global metropolitan areas are implementing a vast number of technology, energy, transportation, and Internet projects to make the metropolis a friendlier, greener, safer, and more sustainable place to be.
Here’s a look at robots depicted in movies and on TV during the 1950s and 1960s. We tried to collect the classics here, omitting the scores of forgettable B movies such as Santa Claus Conquers the Martians and Dr. Goldfoot and the Bikini Machine. Stay tuned for slideshows of robot stars from later decades.
Design News Webinar Series
7/23/2014 11:00 a.m. California / 2:00 p.m. New York
7/17/2014 11:00 a.m. California / 2:00 p.m. New York
6/25/2014 11:00 a.m. California / 2:00 p.m. New York
5/13/2014 10:00 a.m. California / 1:00 p.m. New York / 6:00 p.m. London
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Aug 4 - 8, Introduction to Linux Device Drivers
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  6


Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Next Class: August 12 - 14
Sponsored by igus
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Copyright © 2014 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service