Game Boy Color Linear Regulator Replacement

Replacement part for the linear regulator U7 on the Game Boy Color. Reduces power usage a tiny bit and saves resources from the main PSU.

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The original linear regulator was designed to use the 5V of the main regulator board and drop that down to 3.3V. This is very inefficient since you first go through the efficiency of the main power supply (unknown) and then drop a lot of that power (33%!) again over the linear regulator.

In practice, only very little power is used on the 3.3V rail (I measured roughly 4 mA), so YMMV. You'll maybe get like another half an hour of extra battery life, but why the heck not, right?

The replacement part is a highly efficient switch mode power supply chip with some support parts on a tiny PCB that fits right on top of the SOT-23-5 pads of the original regulator. It also skips the main power supply completely and instead gets its power directly from the battery via the power switch.

To use it, remove the SOT-23-5 linear regulator `U7` from the board and solder the replacement to the two outer-most pads of the 3 pads on the bottom. The middle pad on the bottom and the two pads on top will not be soldered. Then solder a wire to the power switch pad labeled `C` and the pad on your replacement part. That's it! The PCB fits very nicely in there and is held on by the two pad connections to the main PCB of the GBC.

While you're at it, replace the electrolytic caps `C32`(100µF, 6V), `C35` (22µF, 16V) and `C38` (100µF, 4V) on the bottom portion of the main PCB near the batteries with new ceramic or tantalum caps.

That's it, have fun!

Gerber file for PCB manufacturing.

x-zip-compressed - 14.51 kB - 02/06/2024 at 18:16




Adobe Portable Document Format - 16.03 kB - 02/06/2024 at 18:16



Bill Of Materials

ms-excel - 405.00 bytes - 02/06/2024 at 18:16


  • 1 × PCB
  • 1 × TLV61225DCKR Power Management ICs / Battery Management ICs
  • 2 × 10µF, 6.3V MLCC caps
  • 1 × 4.7µH inductor (current rating is not so important)

  • 1
    Solder components to PCB

    Solder all four components to the PCB: Power supply chip, inductor and the two ceramic caps.

  • 2
    Remove U7

    Remove the original linear regulator from the GBC mainboard.

  • 3
    Mount replacement part

    Solder the replacement part from step 1) to the two outer-most pads of the 3 pads on the bottom. The middle pad on the bottom and the two pads on top will not be soldered.

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