Question What exactly is the U10 chip?

Discussion in 'General Discussion' started by loopj, Feb 26, 2020.

  1. loopj .

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    Hey all, I'm wondering if anyone has discovered exactly what the U9/U10 chip is. I'm trying to figure out if it is an off-the-shelf, commercially available component, or a custom chip that Nintendo or one of it's partners made?

    It looks to be a SSOP5 package (the same footprint as a transistor SOT23-5 package) but since it is labelled U9/U10 rather than Q9/Q10 I'm 99% sure this is not a transistor.

    One of my U10's that I damaged during desoldering has the marking B37G.

    I'm wondering for a couple of reasons: a) I'm curious about the role this mysterious component performs, and b) I'm wondering if drop-in replacement chips can be found on mouser/digikey for people who damage their U9 and U10 chips.
     

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  2. YveltalGriffin .

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    The U10 is a supervisory IC that generates a delayed 3.3V signal. It sends the signal to the Wii's Hollywood, letting it know that it's good to go to boot up.

    It's probably pretty similar (if not identical) to this voltage detector IC: https://fscdn.rohm.com/en/products/databook/datasheet/ic/power/voltage_detector/bd45xxg-e.pdf

    Technically, the U10 could be replaced with a different voltage detector IC, a microcontroller, or even a physical switch. But the U9/U10 is the simplest and smallest solution that exists, so there's no real reason to replace it. Plus, you get two of them for free with every Wii! ;)
     
  3. loopj .

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    Interesting, so it looks like a ROHM BD45332G (3.3v, 200ms delay, open drain) or ROHM BD46332G (3.3v, 200ms delay, CMOS) might be a drop-in replacement. I can't tell at a glance if the open drain or cmos model is the correct one here.

    In my case, I damaged U9 and U10 by being too clumsy with my removal. I'm thinking spending a couple of dollars on some replacement chips is cheaper than me buying a new motherboard.
     
  4. jefflongo Broke BitBuilt Staff Member . .

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    I would wager probably CMOS because there's no pullups on the output. IIRC the function is to time a reset interrupt on the Hollywood after it has ample time (200ms) to power up. @Aurelio knows for sure I believe.

    I would be interested to see if this would work as a drop in replacement. I think it actually could work.
     
  5. Aurelio The Fixer ᕕ( ᐛ )ᕗ Staff Member . . . . .

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    On the Wii motherboard there's actually a 4.7k pullup on the u10 output, but when we trim the wii we get rid of it. This makes me think that even if there's a pullup, the IC they used is CMOS.
     
  6. loopj .

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    Thanks jeff, aurelio!

    I'm going to buy a few BD46332Gs with my next digikey order and try one out (for science). Will report back.
     
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  7. Stitches 2 and a Half Dollarydoos Staff Member . .

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    [​IMG]
     
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  8. superior1777 .

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    @loopj any updates on the science experiment?
     
  9. loopj .

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    Look what arrived


    Will try adding it to a fresh mobo.
     
  10. YveltalGriffin .

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    I'm eager to see if you can get them working. I ordered a couple a few weeks ago and couldn't get them to work on untrimmed or trimmed mobos. A deeper read into the DS indicates that the ER line might need to be pulsed to start the POR timer, but it also says that you can tie ER to GND if it's unused (which is what U10 seemingly does)
    Screenshot_20200317_214422_com.google.android.apps.docs~2.jpg
    Screenshot_20200317_214408_com.google.android.apps.docs~2.jpg
    The sheet also shows application circuits with ER grounded. But I couldn't get the ICs to output 3v3 at all, even just hooked up to my benchtop PSU. Probably just a dumb mistake on my end. Please keep us updated!
     
  11. loopj .

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    Just tried this out on an untrimmed 6 layer RVL-CPU-30.

    Bad news, as YvenltalGriffin says it does not work as a straight swap out, the Wii does not boot.

    I confirmed my wiring is ok by removing the chip and replacing with the stock U10, and the console boots.

    [​IMG]
     

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  12. Stitches 2 and a Half Dollarydoos Staff Member . .

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    At least the science was done
     
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