single lm339

Thread Starter

kubeek

Joined Sep 20, 2005
5,794
Hi,
i´m looking for a chip with a single comparator similar to lm339, the most limiting thing is the power supply range from 2V.
Do you know anything that I could use, or do I just need to stick with the 4pack?
 

tom66

Joined May 9, 2009
2,595
LM311 is a single comparator version of the LM339.
LM393 is a dual comparator version.

The LM311 also has another pin the others do not. It connects to the emitter of the transistor. If you're using a circuit designed for an LM339, connect this to the V- pin. Otherwise, it provides a convenient breakout.
 

Thread Starter

kubeek

Joined Sep 20, 2005
5,794
OK, i found that LM311 is not the same as 1/4 LM339, because it works only from 5V supply. But the LM393 is the same as 339, and as i am thinking about it i will use it, because a single comparator will be in 8pin package anyway.
 
Last edited:

SgtWookie

Joined Jul 17, 2007
22,230
I'm afraid that you have misinterpreted the datasheet.

It will operate from a single 5v supply rail. However, the absolute maximum differential for an LM311's supply rails is 36v (ref: National Semiconductor datasheet Jan 2001)
http://www.national.com/ds/LM/LM311.pdf

You can certainly use an LM193/293/393/2903 dual comparator. Make certain to ground the inputs of the unused half, or you may experience odd problems (high-speed oscillations disturbing the half you are using).
 

Thread Starter

kubeek

Joined Sep 20, 2005
5,794
Of course it works with higher supply, but in the OP I stated that I need it to work form 2V supply like the 339 does. Thanks for the help anyway.
 

Wendy

Joined Mar 24, 2008
23,415
An LM393 has virtually identical specs, including the 2V power supply. What is the deal?

Given the package of a LM393 is an 8pin DIP, and would be the same between a single and a dual, there isn't really an advantage for a single comparitors IMO, while the LM393 is directly equivalent to the LM339 other than package layout.
 
Hi,
i´m looking for a chip with a single comparator similar to lm339, the most limiting thing is the power supply range from 2V.
Do you know anything that I could use, or do I just need to stick with the 4pack?
TL331. costs more than LM339 though, but smaller.
 
Last edited by a moderator:

WBahn

Joined Mar 31, 2012
29,979
I criticized the post last night and I was told newbie necroposts must now be APPROVED by a moderator - this post was approved because of the educational merit. I'm not joking.
It was likely approved because it was on-topic. We used to delete necroposts as a rule unless there was a compelling reason not to, but several established members complained saying that it was too heavy handed and that as long as the new post was on topic that it might stimulate useful further discussion. So the guidance was revised so that necroposts will generally be approved unless they are otherwise in violation, such as hijacking or spamming. As is always the case, you we can't please everyone, so of course now members complain about approving necroposts that are on topic.
 

GopherT

Joined Nov 23, 2012
8,009
It was likely approved because it was on-topic. We used to delete necroposts as a rule unless there was a compelling reason not to, but several established members complained saying that it was too heavy handed and that as long as the new post was on topic that it might stimulate useful further discussion. So the guidance was revised so that necroposts will generally be approved unless they are otherwise in violation, such as hijacking or spamming. As is always the case, you we can't please everyone, so of course now members complain about approving necroposts that are on topic.
Thank you for the clear explanation of the current policy your team is using.
 

crutschow

Joined Mar 14, 2008
34,285
My only comment is that there should be an indication in the thread listings that it is a necropost, so that we don't go off and running, replying to previous questions in the post without noticing the age of the posts (which I've done a few times :oops:.)
 

WBahn

Joined Mar 31, 2012
29,979
My only comment is that there should be an indication in the thread listings that it is a necropost, so that we don't go off and running, replying to previous questions in the post without noticing the age of the posts (which I've done a few times :oops:.)
I recommended that a couple of times even before I became a mod. I think it would be quite useful. Apparently it's not a readily available plug-in, so unless there's an admin up to the programming....

Once possibility which might be easier is to color code the top bar of a post to reflect it's age. Perhaps make it yellow (at least on the Blue scheme). The new post would still be the new post color, but the prior posts would be highlighted as being old. That would help, though some things would still fall through the crack, such as the new post starting a new page.
 
Top