Connect with us

Breadboard Power 3.3V for ICs

Discussion in 'Electronic Basics' started by GT, May 9, 2005.

Scroll to continue with content
  1. GT

    GT Guest

    Hi -

    I want to experiment with 3.3 Volt IC chips (LVTTL and LVCMOS33) on my
    breadboard. I need to power the chips and I was wondering if it is OK to
    just have a 5VDC (1.5Amp rated) wall transformer and then use LM317 to make
    a 3.3Volt source for my chips?

    Thanks for any advice or info!
     
  2. John Fields

    John Fields Guest

    ---
    Frayed knot. According to Nationals's data sheet:

    http://www.national.com/ds/LM/LM117.pdf

    You need at least 3 Volts of headroom, which mean that for 3.3V out
    you need at least 6.3V in.

    What you need is a regulator with a low droput voltge, something like
    an LM3940:

    http://www.national.com/ds/LM/LM3940.pdf
     
  3. The LM117-317s specifications include a minimum of 3V between in- and
    output. It may work a little below that voltage or not. The 1.7V however for
    sure is to low to make an LM317 work well. Look for an LM1117-3.3. It works
    well from an 5V input and can provide up to 800mA at 3.3V.

    petrus bitbyter
     
  4. Guest

    OK idea, just the wrong chip. Try an LM3940 from National.
    GG
     
  5. Paul Jones

    Paul Jones Guest

    The lower the voltage the wore the loss in the diodes ....hmmm
    But who wants to do syncr' rectification using a POWER FET !
    The N-ch FET works both ways , Drain neg or pos

    But you want simple ....

    The simple is buck regulator . It's the simplist switcher out ther
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-