LM2577-12 5v to 12v help

Discussion in 'The Projects Forum' started by StealthRT, Aug 19, 2009.

  1. StealthRT

    Thread Starter Active Member

    Mar 20, 2009
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    Hey all i am in need of so help with a parts list for the following diagram:
    [​IMG]
    Here is the parts list:
    Problem i am having is that i dont know which of each to get.

    - For the Caps, should i get Ceramic or Film?
    - for the resistor, should i go with Carbon film or Metal film?
    - For the wire coil inductor, 100uH, im not sure which to go with. A lot are listed so i was wondering what would be best for this project.

    As for some background in what i will be using this 5v to 12v step-up circuit for is for a SATA hard drive to provide 12v to it.

    Any help would be great :)

    David
     
  2. n9352527

    AAC Fanatic!

    Oct 14, 2005
    1,198
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    You can use ceramic caps for the small ones. The output filter cap has to be electrolytic with low ESR. These are special ones intended for SMPS to reduce the ripple voltage.

    Carbon or metal film resistors are fine.

    The inductor needs a minimum staturation current (Isat). See the datasheet of LM2577 to find out the recommended value, and you can choose any 100uH inductor with higher Isat spec.
     
  3. StealthRT

    Thread Starter Active Member

    Mar 20, 2009
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    Hey thanks for the reply!

    Ok here is the list. If you could, double-check it for me and see if i got the correct parts :)

    LM2577T-12-NDIC REG SIMPLE SWITCHER TO-220-5
    2.2KQBK-NDRES 2.2K OHM 1/4W 5% CARBON FILM
    0BC1148CT-NDCAP .10UF 25V CERAMIC +80/-20%
    490-3832-NDCAP CER 330000PF 50V X7R RADIAL
    P10330-NDCAP 680UF 50V ELECT FC RADIAL
    1N5822DICT-NDDIODE SCHOTTKY 40V 3A DO-201AD
    M8324-NDCHOKE RF HI CURRENT 100UH 1.6A

    David
     
    Last edited: Aug 20, 2009
  4. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    National often has a list of "tested and recommended" components in its datasheets. That will be an aid in selecting the electrolytic capacitor to have sufficient ripple current rating.

    John
     
  5. StealthRT

    Thread Starter Active Member

    Mar 20, 2009
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    Cant really find what to look for in all that. I'm looking to order the parts today so it would be great if someone could let me know if the parts list i posted above will work fine with what i am going for.

    Thanks! :)

    David
     
  6. bertus

    Administrator

    Apr 5, 2008
    15,649
    2,348
    Hello,

    Like jpanhalt told you there are recomendated parts in the datasheet:

    [​IMG]

    This picture is taken from the datasheet.

    Greetings,
    Bertus
     
  7. Steve C

    Active Member

    Nov 29, 2008
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    wow, dumb question, I was looking at the datasheet for this device.

    It can take anything from 3.5vdc to 40vdc and supply a constant 12vdc at max 800mA?

    Does this mean it can be placed in the automotive environment powering a device that takes 400mA and accept WILD WILD voltage swings without hiccupping the output voltage?
     
  8. StealthRT

    Thread Starter Active Member

    Mar 20, 2009
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    That really doesnt help me, Bertus. As it only tells the values of the components (just like the picture i posted does as well). I was looking for actual part numbers of those components so that i wouldn't get some with the wrong values, tolerances, etc etc.

    David
     
  9. Steve C

    Active Member

    Nov 29, 2008
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    What is comp and why do we need it in the circuit?
     
  10. StealthRT

    Thread Starter Active Member

    Mar 20, 2009
    223
    0
    Bump.. still need help with this :)

    David
     
  11. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    What help have you been waiting so patiently for? When last visited, you had a parts list and we directed you to the datasheet for a few details. As I recall, you were unsure of the inductor. Here is a portion of the datasheet giving part numbers for the L100 inductor that are known to work.

    [​IMG]

    Immediately under the table, the address and telephone numbers for each manufacturer is given. Analogous information is given for the electrolytic capacitor.
    John
     
  12. StealthRT

    Thread Starter Active Member

    Mar 20, 2009
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    Yeah, these parts are non-extinct on digi key.

    David
     
  13. Steve C

    Active Member

    Nov 29, 2008
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    That's the problem with spell checker. The most famous example I remember was from a printed itinerary for a llamaze class, with one title in caps and bold: "beast feeding for beginners"

    http://www.mouser.com/Search/Refine.aspx?Keyword=PE-92108

    That was just the first search attempt. The others might show up in searches too.
    I also didn't check jameco or halted or advanced component or excess solutions.
     
  14. StealthRT

    Thread Starter Active Member

    Mar 20, 2009
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    :rolleyes: Mouser does not carry National Semiconductor products..

    David
     
  15. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Are you sure they are non-extinct?

    John
     
  16. StealthRT

    Thread Starter Active Member

    Mar 20, 2009
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    yes, on digikey.

    David
     
  17. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Why don't you go with the LM2700MT, as suggested in your other thread. It's cheaper, more efficient, and the entire BOM is available from National for $4.14, excluding the PCB.

    John
     
  18. StealthRT

    Thread Starter Active Member

    Mar 20, 2009
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    What are the values that you are putting in for:

    V in Lower
    V in Upper
    V out
    I out
    Ambient Temperature

    ? I keep getting "recommended Devices" or "BOM kit not available for this selection"

    David
     
  19. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    What values do you want? Somewhere you stated that you wanted 5V in. That is Vin lower. You wanted 12 V out. That is V out. You wanted 800 mA out (maximum). That has to be converted to Amps, so its 0.8 A for I out. Ambient temperature depends on where the project will be used. When I entered the values, it defaulted to something like 25 to 30°C, which seems reasonable for most indoor locations. It is a relatively unimportant entry for this project.

    That answers all of the inputs, except Vin upper. On another forum, you claimed to have tried lots of values, but nothing worked. What values did you try? You are building a boost regulator, right? You probably do not want a buck-boost version. So, for your upper value put in any number between 5V and 12V. I used 12V and the program worked fine.

    You have multiple threads on this project on this and at least one other forum. That is fine, but those threads seem to be going nowhere, and you seem to be getting distracted as to your goal. You are receiving lots of advice, some good and some frankly wrong. I can assure you that Webench works. Don't give up because of some disgruntled former National employee. I have used it for my own projects, and I used it to obtain the BOM, PCB, ordering information for your project. In fact, I went through the screens until I got to the point where I had to order the items/kit. At this point, I wonder whether you are you are putting an earnest effort into the project.

    Have you considered:
    1) Buying an up converter at your local PC store or over the Internet?
    2) Paying someone to build, test, and send a unit to you?
    3) Paying someone to order the parts for you?

    Unfortunately, option 3 would only get you the parts. You would need a PCB board designed and etched, and you would need to assemble and test it. You are surely going to run into greater obstacles in doing that than you have faced in ordering a few common parts.

    John
     
  20. StealthRT

    Thread Starter Active Member

    Mar 20, 2009
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    Thanks for taking the time to type all that jpanhalt.

    I finally got something with those values. It will be interesting to see if i can put it together since it only lists SMS parts and not through-hole parts as well.

    David
     
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