Rail-to-Rail Inputs—what you should know!

RE: Rail-to-Rail Inputs—what you should know!

Jens-Michael Gross — Mon, 22 Apr 2013 18:19:51 GMT

Bruce, I don't think it would have been wasted time - I just never had the idea to think about it at all. This is one of these things you just take for granted - until it turns against you. (In which case I surely had invested some time to fuigure out what's going on).

Sometimes you only know that something is worth thinking about it when you already thought about it for some reason. And it's definitely better to get alerted by this blog post then by a non-working circuit. :)

RE: Rail-to-Rail Inputs—what you should know!

Bonnie Baker - WEBENCH Design Center — Fri, 19 Apr 2013 17:54:05 GMT

The amplifier configuration that is geneally immune to this input stage issues is the inverting configuration. If you are willing to live with an inverted or a signal that changes from + to - or - to + this amplifier topology is good for you. Also, if you configure you non-inverting amplfier circuit in a gain of (typically) 2 or higher you will also avoid this input stage problem.

RE: Rail-to-Rail Inputs—what you should know!

Bruce Trump — Thu, 18 Apr 2013 20:30:23 GMT

Jens-Michael-- I realize that you are a true MSP430 guru but you should never refer to time spent thinking about analog issues as possibly “a wasted thought,” as you put it. :-) Thanks for your comments.

For those who are not familiar with Jens-Michael, I suggest that you check this link... sorry, I can't hyperlink it in these comments.

e2e.ti.com/.../jens-michael-gross-engineer-and-social-media-guru.aspx

He is, by far, the most prolific E2E community member. Come on you analog peeps... step it up! Give Jens-Michael some competition. -- Bruce

RE: Rail-to-Rail Inputs—what you should know!

Jens-Michael Gross — Thu, 18 Apr 2013 18:14:01 GMT

Thank you for this article. I never wasted a thought on how R/R is accomplished. And on large signal, it usually is a don't care anyway. But for audio use, teh dual input stage can create even audible artifacts, depending on signal composition. On my next audio project (which I have planned adn then postponed for ~15 years now) I'll definitely consider this. Especially the part with the transition point ending up mid-suipply (on an audio applciaiton this is the worst case: around zero voltage, where noise and artifacts are best audible.