Digikey Typo?

Discussion in 'The Projects Forum' started by jp1390, Aug 23, 2011.

  1. jp1390

    Thread Starter Member

    Aug 22, 2011
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    Hi all, just a quick question regarding a Digikey part that I want to buy.

    Digikey:

    http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=P143-ND

    Datasheet:

    http://panasonic.com/industrial/includes/pdf/Panasonic_Lithium_BR2325_BR2330.pdf

    I need two small 6 V batteries for my circuit and I found this Panasonic 6 V 23 mm coin battery. The only problem, is that when I check the datasheet it says that the nominal voltage is 3 V.

    Is that a typo on Digikey's part?

    Side note:

    I am wondering if I should just buy two 3 V coin cells, because I know they exist and boost the voltages to 6 V each for my op amps. I need +/- 6 V dual supplies for my op amps, does anyone have a recommendation for DC/DC converter setup to use?

    Thanks!
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Yes, it's a Digitypo. ;) Believe the datasheet; they are the manufacturer's final word.

    Instead of using a boost circuit, consider stacking a couple of coin cells. You'll get more than twice the life out of them.

    You don't say what kind of boost you need. The ICL7660 is a very efficient capacitive switching boost converter, but it has a limited current output.
     
  3. jp1390

    Thread Starter Member

    Aug 22, 2011
    45
    2
    Thanks, I figured it was too good to be true.

    I was thinking about using multiple coin cells, but I was worried about how much space they would take up. I need steady +/- 6 V supplies and that would require four coin cells! I guess I will need some sort of regulator for these as well?

    As for the boost converter option, I am dealing with currents in the system below ~10-30 mA, so I am wondering if that will limit my options drastically.
     
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    10mA is about the limit for the ICL7660. It also has a ~200uA standby current when not under load, so that will also tend to drain your batteries. Switching supplies are pretty noisy, too. If you're using switching supplies in an analog system, you are inviting noise to give you big headaches.
     
  5. jp1390

    Thread Starter Member

    Aug 22, 2011
    45
    2
    Fair enough, plus the circuits for boost converters seem to add more undesired headaches and components.

    If you don't mind, if I end up purchasing the four batteries, is there a reliable way of regulating them at +6 V and -6 V for each pair?

    Heck, I might as well just get two 9 V batteries and use a 7806/7906 combo.
     
    Last edited: Aug 23, 2011
  6. jp1390

    Thread Starter Member

    Aug 22, 2011
    45
    2
    I also just spoke with a Digikey technical rep, and they told me that it is indeed a 6 V battery, but it composed of two 3 V batteries sealed together with heatshrink. I wish they were more clear on that though... Oh well.
     
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