This IC is from an auto radio. I don't know what caused the problem but I need this one.

photo of the IC

  • \$\begingroup\$ alldatasheet.com/view.jsp?Searchword=39AA \$\endgroup\$
    – Mitu Raj
    Jun 24, 2022 at 11:53
  • \$\begingroup\$ the prefix is not the same as the SMD code @MituRaj \$\endgroup\$ Jun 24, 2022 at 12:02
  • 2
    \$\begingroup\$ Most of the time, it's hard to identify a component without seeing the rest of the circuit. Since the markers often don't reveal the chip type, we need to see the entire circuit too, or at least what other things the IC connects to. \$\endgroup\$ Jun 24, 2022 at 12:09
  • \$\begingroup\$ Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking. \$\endgroup\$
    – Community Bot
    Jun 24, 2022 at 12:10

1 Answer 1


Without knowing what the function of the circuit is, best guess would be MIC2039AYM6 from Micrel/Microchip. The MIC2039 is a high side adjustable current-limit load switch

The reasoning is as follows. While you don't give a size of the IC or much to scale off, the part closely resembles a SOT23-6 package, so we will assume that is the case. Looking for parts marked 39AA in a SOT23-6 package, the MIC2039 comes up. The datasheet then goes on to give information about how the package is marked:

Package marking for MIC2039

Interestingly here is specifically shows that there is an underscore beneath the first portion of the part number, which matches what we see in the image. While the underscore in the image is only under the 39 rather than the 39A of the datasheet, it goes on to provide "Note 1. Under-bar symbol ( _ ) may not be to scale", so that is not an issue.

Next lets see if the pinout matches.

Pinout for MIC2039

Here we see that GND is on pin 2, which although hard to tell from the image, does appear to connect to a large power plane in the image.

Pin 5 is the current limit setting pin which should have a resistor to GND. Again in the image there is what appears to be a trace going off the a resistor. Whether that resistor is got GND I cant tell.

Pin 1 should go to Vin. This looks like it goes to a large capacitor, so again that would make sense.

Pin 6 goes to Vout, and in the image this seems to be a second power plane (hard to tell), so again that would be a match.

Annotation of image showing where traces appear to be

  • 1
    \$\begingroup\$ Wow Tom how did you find that IC? Did you type something on google or do you have a program or book to find the parts? \$\endgroup\$
    – mehmet
    Jun 24, 2022 at 12:38
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    \$\begingroup\$ @mehmet just typed "sot23-6 39aa" into Google. This was third result. Normally it can be a bit more tricky. \$\endgroup\$ Jun 24, 2022 at 12:39
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    \$\begingroup\$ The google-fu is strong with this one. \$\endgroup\$
    – winny
    Jun 24, 2022 at 12:53

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