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Searching equivalence for MN13811 Voltage Regulator for BS2 OEM — Parallax Forums

Searching equivalence for MN13811 Voltage Regulator for BS2 OEM

FlotulFlotul Posts: 24
edited 2006-03-15 05:21 in General Discussion
Trying to build my own "OEM" board, I can't find the MN13811 Voltage Regulator component; not even an equivalence.

Does somebody have a idea what component currently replaces the MN13811?

Comments

  • ForrestForrest Posts: 1,341
    edited 2006-03-14 17:35
    The BS2 OEM uses the LM2940, which is a +5V regulator. If you don't need the brown-out/reset function of the MN13811 regulator, then you can use the LM2940 which is around $1 and readily available.
  • FlotulFlotul Posts: 24
    edited 2006-03-14 21:56
    Honestly, I'm not good enough in electronic to know if this brown-out function is necessary.

    I'm just surprised that you say "The BS2 OEM uses the LM2940...". Actually, the schematic I have downloaded from PARALLAX.COM mentions the MN13811 (see attachement).

    May I kindly ask to compare the attached schematic with the one you have and let me know if they are (almost) same?

    Thank you anyway, I'll try out the LM2940 wink.gif

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    Roger

    Savigny, SWITZERLAND (french speaking part)
    pdf
    pdf
    bs2oem.pdf
    11K
  • Jon WilliamsJon Williams Posts: 6,491
    edited 2006-03-14 23:34
    Flotul said...
    Honestly, I'm not good enough in electronic to know if this brown-out function is necessary.
    With that sentiment in mind, why not just copy our OEM circuit since you can be assured that it works when correctly assembled.

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    Jon Williams
    Applications Engineer, Parallax
  • RDL2004RDL2004 Posts: 2,554
    edited 2006-03-15 03:32
    Hello Flotul,

    In the schematic you posted, the big yellow box in the upper right labeled VR1 with LM2940-5.0 written just above it, is the voltage regulator. The MN13811 is there to force a re-set of the Stamp if the supply voltage drops below a certain level (which is preset inside the MN13811). This chip is made by Panasonic, and is available here in the U.S. from Digi-Key. This type of device is known as power supervisor or reset supervisor (or sometimes supervisory chips). There are similar devices available from other manufacturers and suppliers. I have to admit, I'm not sure why this re-set function is necessary, but I suppose data corruption is a likely reason.

    The only reason I know this is because last year I was planning to build my own BS2 as you are. I have yet to complete that project, but I remember I asked here what the MN13811 was for when I was doing my research. I think in many cases you can do without this chip, however, as Jon has suggested, I chose to duplicate the Parallax circuit, though the part I selected was from ST Micro and not Panasonic.

    I hope this info was of help [noparse]:)[/noparse]



    - Rick
  • FlotulFlotul Posts: 24
    edited 2006-03-15 05:21
    Thank you All for your informations.

    Yes Jon, I'm not wanting to re-invent the wheel. I'm actually using PARALLAX's schematic. The only issue I have is to find this MN13811. I really appreciate how much info I can get from PARALLAX.

    Thank to you, Rick, I know now where I can find this part.

    Great smile.gif

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    Roger

    Savigny, SWITZERLAND (french speaking part)
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