HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
  |  REGISTER  |  LOGIN  |  HELP
Comments
View Comments: Newest First|Oldest First|Threaded View
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.

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.

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!

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
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!





Partner Zone
Latest Analysis
Enabling the Future is designing prosthetic appendages modeled more like superhero arms and hands than your average static artificial limbs. And they’re doing it through a website and grassroots movement inspired by two men’s design and creation in 2012 of a metal prosthetic for a child in South Africa.
In order to keep an enterprise truly safe from hackers, cyber security has to go all the way down to the device level. Icon Labs is making the point that security has to be built into device components.
Senior Technical Editor Chuck Murray gets the skinny on Harting Inc.'s 3D MID technology, which allows users to create a three-dimensional circuit board out of molded plastic.
Three days after NASA's MAVEN probe reached Mars, India's Mangalyaan probe went into orbit around the red planet. India's first interplanetary mission, and the first successful Mars probe launched by an Asian nation, has a total project cost of nearly $600 million less than MAVEN's.
Siemens PLM Software has made an in-kind donation of software to Central Piedmont Community College in North Carolina for its science, technology, engineering, and mathematics (STEM) Division.
More:Blogs|News
Design News Webinar Series
9/25/2014 11:00 a.m. California / 2:00 p.m. New York
9/10/2014 11:00 a.m. California / 2:00 p.m. New York
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
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Oct 20 - 24, How to Design & Build an Embedded Web Server: An Embedded TCP/IP Tutorial
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: September 30 - October 2
Sponsored by Altera
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