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7805 substitute — Parallax Forums

7805 substitute

Robert SchwartzRobert Schwartz Posts: 141
edited 2005-02-26 02:11 in General Discussion
Hey guys. I was wondering if there is a good substitute for the 7805 regulator. I know about the LM2937, but not much. Is it pin for pin compatable with the7805? Is it better/more efficient? Thanks.

Comments

  • kb2hapkb2hap Posts: 218
    edited 2005-02-08 03:45
    could you be more specific.· what are you looking for exactly?· more amps, better efficiency, different package?

    you make want to just take a look at the various suppliers

    www.mouser.com

    www.jameco.com

    www.digikey.com

    www.newark.com

    thats just to name a few...most of then also supply data sheets which can give you information on pin compatability and how to use/interface them.

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    DTQ
  • Robert SchwartzRobert Schwartz Posts: 141
    edited 2005-02-09 00:00
    Thanks kb. Has anyone heard of or used the Microchip TC1262?
  • Robert SchwartzRobert Schwartz Posts: 141
    edited 2005-02-09 00:02
    I am looking mostly for a lower dropout and more effieciency.
  • BeanBean Posts: 8,129
    edited 2005-02-09 02:27
    For 150mA or less check out the TL750L05CLP from TI.
    It is a TO92 package with a dropout of 0.2V @ 10ma and a max loss of 0.6V at 150mA
    Plus it's cheap. Only $0.68 for 1 pcs from digikey.
    Bean.


    Post Edited (Bean) : 2/9/2005 2:30:12 AM GMT
  • Robert SchwartzRobert Schwartz Posts: 141
    edited 2005-02-09 03:47
    Thanks bean, but I'm going to need at least 300-400 ma.
  • Mark GMark G Posts: 11
    edited 2005-02-09 17:45
    Scott Edwards Electronic site has a good schematic for a 5VDC power supply which uses either a 7805 OR 78ST105HC.

    http://www.seetron.com/an_vpwr1.htm

    I have built the 78ST105 version and have been very happy with its performance...
  • Jim G.Jim G. Posts: 27
    edited 2005-02-09 21:27
    I am currently working on a project that has a 24VAC power source that I·am using for my 5VDC supply.· This heats up a 7805 even at low currents.

    To be more "green", and also to experiment a little, I have been looking at a buck-type switching regulator, LM2574-5 from Micrel, http://www.micrel.com/.· I have avoided these circuits in the past because they seemed too complicated, but it's not so bad these days; they only use 4 external components.

    I haven't actually fired one of these up yet, but I plan to try it out.· It will be more expensive to use this type of regulator, around $4(?) for it and all the external parts, but it is worth checking out.

    Jim
  • MacGeek117MacGeek117 Posts: 747
    edited 2005-02-09 22:03
    Or you can check out Karl Lunt's book BUILD YOUR OWN ROBOT! and look for the
    JBS (Junk Box Switcher).
    bugg

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    So many projects, so little time.
  • Robert SchwartzRobert Schwartz Posts: 141
    edited 2005-02-10 01:07
    Thanks guys. I think I found what I needed though, the MAX603. I ordered a few so I'll see how well the work. Mark, that power supply liked pretty nice for getting higher voltages down to 5. I'm probably going to be using that in a different part of my project. Jim, those regulators do look nice, but they are pretty expensive, and I don't feel like ordering them in 50pc rails. Thanks though.
    Robert
  • Beau SchwabeBeau Schwabe Posts: 6,568
    edited 2005-02-25 22:43
    Here are a few low dropout regulators that have just been released...

    Low-Quiescent CMOS Regulators - February 23, 2005 News Release

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    Beau Schwabe - Mask Designer III

    National Semiconductor Corporation
    (Communication Interface Division)
    500 Pinnacle Court, Suite 525
    Mail Stop GA1
    Norcross,GA 30071
  • Robert SchwartzRobert Schwartz Posts: 141
    edited 2005-02-26 02:11
    Wow, only 1uA shutdown draw, and 100uA max draw. Thanks Beau, those are pretty much exactly what I was looking for.
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