1
\$\begingroup\$

It is this SOIC chip you find on AliExpress 5 V, 3 A buck converters.

This particular chip is labeled GKEOE. The one I have at home is labeled HqDAB. I can't find anything about them.

enter image description here

Searching on AJ38 I only find this board.

Can somebody tell me what ICs these are?

\$\endgroup\$
6
  • \$\begingroup\$ Probably some ultra-cheap buck converter with integrated switch from a company that doesn't sell outside of China. You'd probably have better luck looking for equivalents from TI or LT or Maxim or someone. \$\endgroup\$
    – Hearth
    Commented Dec 18, 2022 at 20:51
  • \$\begingroup\$ In case you are thinking of reverse engineering a design like this, the best approach is start from scratch with reputable sources that have a QA system and are supplemented with decent data sheets. Simulate and build. If on the other hand you have blown the module up and are looking for a replacement, you might just be perpetuating a poor design by fixing it. \$\endgroup\$
    – Andy aka
    Commented Dec 18, 2022 at 21:06
  • \$\begingroup\$ I use these boards alot to power 5v servo's. I made a footprint for these boards and I solder them flat to my own designs like a backpack. So far they have not exploded... What intrigued me a little bit is that they supposedly can supply up to 3A (not tested it myself) and they don't have an elco on board. So either it is lacking and you are to add an elco yourself or it is simply not needed. \$\endgroup\$
    – bask185
    Commented Dec 18, 2022 at 21:13
  • 1
    \$\begingroup\$ @bask185 What's an elco? \$\endgroup\$
    – Hearth
    Commented Dec 18, 2022 at 21:14
  • \$\begingroup\$ It is an abbreviation for Electrolytic capacitor. 'Elco' is commonly known in atleast the Netherlands. But apparantly it is not so well known internationally? \$\endgroup\$
    – bask185
    Commented Dec 18, 2022 at 21:16

2 Answers 2

Reset to default
2
\$\begingroup\$

Quite possibly a AP3503F or equivalent - see here - or CN3903 does that seem to match the footprint and connections?

CN3903 - They say:

  • 36V/3A 500KHz Synchronous Buck Converter CN3903
    The CN3903 is a low-EMI signature, asynchronous, step-down, switch-mode converter with internal power MOSFETs. It provides a very compact solution that can deliver 3A of continuous current over a wide input supply range with excellent load and line regulation.
    The CN3903 achieves low EMI characteristics and well-controlled switching edges.
    Fault condition protection includes programmable output overvoltage protection, constant on-time mode and thermal shutdown.
    The CN3903 requires a minimal number of off-the-shelf standard external components.

enter image description here

AP3503F

enter image description here

\$\endgroup\$
0
\$\begingroup\$

You straight-forwardly state what the IC is inside your post - a 5A SMPS. Were you trying to find a pin out? Based on the fact that you found a similar package on two different ICs with different P/N that might point to the fact that it's a common footprint so you should theoretically be able to use the DS you found to find out pin-out.

In any case, you can still find the pin out easily by simply taking a DMM and short testing each pin to see which pins are connected to VDD, GND, near by components, etc. Let me know if you want me to elaborate.

Maybe you can update with a pic of the exact IC you're trying to find. Seeing the surrounding components for that IC would help. Also, if you can mention what the board does. I used to do competitive analysis all the time on PCBs and would have to figure out the exact info you're looking for.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.