sot23 5-lead dc-dc regulator

Discussion in 'General Electronics Chat' started by scscomp, Apr 19, 2013.

  1. scscomp

    Thread Starter New Member

    Apr 19, 2013
    I have a device that does not charge the battery anymore (battery is good). I tracked down the component that regulates the incoming charge going to the battery and, it appears to be a sot23 5-lead. Testing it, 5vdc (from USB source) is coming into the sot but nothing is coming out. The schematic is not available. I know the correct output to the battery should be 4.1vdc. The only marking on the component is the number "3308". When I'm looking for a replacement at a supplier website, what do I search on? Is the polarity of the output voltage important? Also, 3 of the terminals are vin, vout, and gnd. What do the other two terminals do in this application?
    Last edited: Apr 19, 2013
  2. #12


    Nov 30, 2010
    No schematic, no part number, and no information on what you're charging? It will be a matter of luck if anybody knows the answers to this one.

    Low dropout, SOT23-5, voltage regulator...
    scscomp likes this.
  3. #12


    Nov 30, 2010
    Yeah, and on exactly the same question you can't answer. Imagine that!
  4. bountyhunter

    Well-Known Member

    Sep 7, 2009
    Au, contrare.... I spent 25 years working as an application engineer at national Semiconductor. I can personally guarantee you there are millions of fools who can NOT read a data sheet and figure out which end of the part to solder to ground.

    You have 0.9V of drop across the part. You need a LDO linear. You could use something like the LP2981-adj set to 4.1V.
    Last edited by a moderator: Apr 20, 2013