What could this circuit be (I damaged it)?

[240RS]

I damaged the circuit on the bottom left of this microcontroller based development board and have no idea what kind of circuit it is. I do not have schematic.

The 4k7 marked component is an inductor, right? The 6 lead chip right of it has a marking that looks like 8ARM or 8ARU. Opamp maybe?

And the components I knocked off (tried to slide it into something) are those resistors, or can capacitors be that small also?

Any ideas?

Thanks!

[homebrew]

Right, that is a 4.7uH inductor. As it is near the 5V input with the input selector jumper, it looks like a switch mode voltage regulator. The lite chip will be the controller, regulating the output voltage. The broken off components are most likely capacitors. I would try to identify the controller chip and look up its data sheet. You would most likely find a similar schematic there.

Do you have a microscope or a good magnification lens?

Also, if this is a development board, you'll most likely find a schematic online from the vendor.

[RoGeorge]

In that area is a SMPS (Swithing-Mode Power Supply) power supply, most probably from 5 to 3.3V.

That IC is the voltage stabilizer.  The 4k7 is a coil, indeed.  In the same area it is expected to have some resistors (usually black), some capacitors (usually brown), a Schottky diode (also black but usually thicker than an R).

From the picture is not possible to distinguish what or if something is missing.
Try taking a clear picture, with the components in focus.

[240RS]

Aha! SMPS. Won’t work without it then… but also, not too difficult to repair.

The schematic is not available, but of the SOM on the board there is. I will check for voltage levels.

Making better pictures is hard. Will try again tomorrow.

[andru123]

If you cannot even make a focused foto, how are you even going to solder it back?
The circuit with 3 legs is the most important, once you figure what it is, there is usually a ref design with all other components around.

[240RS]

I think I cannot solder that indeed.

Checked the SOM: 3.3V indeed.

Will contact the vendor. Worst case I will add my own 3.3V supply.

[Manul]

In case you will try to repair or check voltages, I strongly suggest that you temporarily cut the output trace, until you repaired it and you are sure that the voltage is correct. A broken buck converter might output 5V into 3V3 rail.

If you know that 3V3 rail current is small, you can also repair the board by putting in a linear regulator instead.

[Shonky]

Small note: The 4k7 is actually 4R7 = 4.7uH (as noted) on an inductor.