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Lt1529 — Parallax Forums

Lt1529

Tricky NekroTricky Nekro Posts: 218
edited 2005-11-10 14:16 in General Discussion
I have some problems finding this regulator in the european market , by digikey...and I must order it from America which is costworthy.
I want to·find other such regulators with a shutdown pin available in the european market...smile.gif

I want to handle about 15 to 5 Volts and about 3Ambs...



Thankfully, Provas, Greece

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
-Rule your Destiny-
--Be Good. Be Bad. Be Provas--

Comments

  • Tracy AllenTracy Allen Posts: 6,666
    edited 2005-11-08 17:52
    Hi Provas,
    I don't know of a substitute offhand. I'm a big fan of Linear Tech products, and they offer quite a few regulators that would work. Is it that Linear Tech products are hard to get in Europe, or the LT1529 in particular? I'm sure there are other companies that make this kind of thing, but parametric search and evaluation can eat up a lot of time.

    Are you developing for a commercial application, or for your own use? If you just need one or two LT1529, I could slip them in an envelope and mail them to you.

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    Tracy Allen
    www.emesystems.com
  • Tricky NekroTricky Nekro Posts: 218
    edited 2005-11-08 21:49
    Yes, it's only for me... I can find Linear Tech products in Greece but I can't find this one(LT1529) , only from America... You know, I'm trying to built a fully functioning Power Board for Servos and I must find a way to shut down the whole power circuit for recharging the battery...

    Thank for your offer to sent some pieces, but if you can suggest me some other such product, it will be alright...



    Thank you,again...

    Provas, Greece

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    -Rule your Destiny-
    --Be Good. Be Bad. Be Provas--
  • Bruce BatesBruce Bates Posts: 3,045
    edited 2005-11-08 22:27
    Provas -

    Take a run over to the Maxim web site: http://www.maxim-ic.com/ and see what you think of one of the following LDR Regulators with shutdown:

    MAX663, MAX666, MAX667, MAX1659

    None of them are exactly like the LT1529, but one or more may be close enough.

    Regards,

    Bruce Bates
  • Tracy AllenTracy Allen Posts: 6,666
    edited 2005-11-09 17:16
    Alternatives from Linear Tech are,
    LT1963 or LT1964, low dropout with shutdown and 1.5A or 3.0A current, 20 volts maximum input
    LT1528 or LT1529, low dropout with shutdown, 3 amps, faster or slower transient response, 15 volts maximum input.

    I've used the LT1963A too, and it is very well behaved and very fast response (designed for the demands of telecom circuits.) I trust that the LT1964 would be similar. Linear Tech parts are always good performers.

    While the parts from Maxim that Bruce suggested are in fact LDOs with shutdown, it does not appear that they meet your amperage requirement.

    BTW, consider substituting a more modern regulator (lower dropout, lower quiescent current) for the 7805. The Parallax boards use an LM2940, I think.

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    Tracy Allen
    www.emesystems.com
  • Tricky NekroTricky Nekro Posts: 218
    edited 2005-11-09 21:26
    What do you mean by lower dropout, lower quiescent current...
    Sorry but my english, you know..........cry.gif


    Thanks once again for your interest...
    Provas, GReece

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    -Rule your Destiny-
    --Be Good. Be Bad. Be Provas--
  • Tracy AllenTracy Allen Posts: 6,666
    edited 2005-11-10 01:12
    lower dropout: The 7805 requires at no less than 7.5 volts at its input in order to provide 5.0 volts at its output. A low dropout regulator like the LT1529 or LT1963 or LM2940 can provide 5.0 volts at its output with only 5.5 volts at its input.

    low quiescent current: This is current that does not contribute to powering the load and flows out of the ground leg of the regulator. The 7805 requires at least 6 milliamps for its own internal operation at all times, even when it is not supplying current at the output. The LM2940 used on the BOE is also _not_ a low quiessent current regulator at 10 milliamps even with no load. Consider, the regulator itself is probably consuming more power than your BASIC Stamp. That constant drain can be a liability in a battery powered system. The LT regulators mentioned above draw much less current when the load is very light. When the Stamp system is asleep, the whole thing can operate on the order of 0.1 milliamp. When the regulator is shut down, the current drops to a few microamps. That is not the whole story, because the low dropout regulators usually have a higher quiessent (wasted ground pin current) when they are called upon to supply high currents. As in all of engineering, there are many interacting factors to consider!

    I am sorry, my Greek is surely worse than your English!

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    Tracy Allen
    www.emesystems.com
  • Tricky NekroTricky Nekro Posts: 218
    edited 2005-11-10 14:16
    Thanks for your repply...

    I have a comment to make...

    I'm not so intrested in the current which is drown although the the LT series drow much less... I have seen that the servos and the whole board goes down when the battery level drops below ~5.5Volts...I have connected two 1000μF caps both in the input and output of the regulator... This must have saved the waterworks...scool.gif

    Καλήμερα (Good morning)

    Provas, Ελλάς, GReece...

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    -Rule your Destiny-
    --Be Good. Be Bad. Be Provas--
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