Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

What parameters are taken care of while designing an op amp as a comparator

Status
Not open for further replies.

Bjtpower

Full Member level 5
Joined
Dec 24, 2015
Messages
297
Helped
2
Reputation
4
Reaction score
2
Trophy points
1,298
Activity points
3,893
What parameters are take care while designing a opamp as a comparator

Hello Guys,

I have cross reference of the one design where they have used LM393 Opam as comparator.

I dont know the paramaters are taken into considerations.

I would like to understand what parameter are taken consideration while designing opamp as a comparators.

Only few termilogy if you know they i can search but pls Suggest.

Thanks

Marx
 

Re: What parameters are take care while designing a opamp as a comparator

Hi,

Are you sure the LM393 is an op amp? My LM2903/LM193/LM393 datasheet says something about a comparator. ;)

AN74 is as useful as the datasheet for some things for the LM139/339. Look at the internal design, so simple and so effective. The main current source is a great block to borrow.

Using Op Amps As Comparators There are a good few of these type of app notes on the web, take a look.

You know it's a "not recommended", don't you? Apparently it's of the category of doable with a spare op amp from a quad if needs or laziness or cost must. They're entirely different things.
 

Attachments

  • AN-74 LM139 etc A Quad of Independently Functioning COmparators snoa654a.pdf
    1.5 MB · Views: 44
Last edited:

Re: What parameters are take care while designing a opamp as a comparator

Yes, the LM393 is a comparator, not an op amp (it can be confusing since they usually use the same symbol for both devices.

The difference is that an op amp has internal compensation so it is stable with negative feedback, while a comparator has no compensation, making it faster as a comparator, but it is unstable in a linear mode with negative feedback.
 

Re: What parameters are take care while designing a opamp as a comparator

The LM393 dual comparator has almost the same circuit as the LM358 dual opamp except without the frequency compensation capacitor and without the push pull output.
 

Attachments

  • opamp or comparator.png
    opamp or comparator.png
    47.7 KB · Views: 161
  • Like
Reactions: d123 and CataM

    CataM

    Points: 2
    Helpful Answer Positive Rating

    d123

    Points: 2
    Helpful Answer Positive Rating
Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top