BGA-9 component identification

[zzattack]

I'm trying to figure out what component we have here.
SMT top marking reads "+ALJ  117". It's a BGA9 package. If the + indeed denotes (I'm not sure) the corner for pin A1, then pins A1/B1 are tied together, A2/B2 are, and A3/B3 are. There's a 1uH inductor between A2/A3 and B2/B3.
On this board C1 and C3 appear to be no connects, and I have not been able to determine where C2 goes yet. Quite possibly a power plane.

Voltage readings are taken on a seemingly working device, but this IC gets very hot (>90°C) very quickly (<5s). I'm worried about powering it on.


The usual SMD top marking databases do not have a corresponding entry for this BGA9. Anyone wanna hazard a guess?

[fzabkar]

I'm guessing that the manufacturer is Maxim:

http://www.smdmark.com/en-US/search/code?id=%2Ba

It looks like a boost converter. Are you sure that your 3.8V and 0V annotations aren't reversed?

The "L" in "ALJ" doesn't look like an L to me. Are you sure about this?

"117" looks like a YWW (Year / Week) date code.

Edit:  Does the circuit take the voltage from a 4V lithium battery and boost it to drive a string of LEDs?

[zzattack]

I expected the + in +ALJ to denote the pin 1, but you're saying it's part of the marking? In that case indeed it is likely a Maxim ic. I found another picture of the board where the same ic is marked +ALJ125 so the date code assumption makes sense.

There is indeed an OLED screen and 3.7 Lipo. What is your guess?

Might be a MAX8969 in WLP9 package.

[fzabkar]

Is the year of manufacture 2021?

If so, then I would search Maxim's web site for suitable candidates. You may need to use the Wayback Machine for earlier years (web.archive.org).

I think this is the sort of chip you should be looking for:

https://www.analog.com/media/en/technical-documentation/data-sheets/3459fc.pdf

[zzattack]

Given the pads layout, recommended sizes for the inductor and decoupling capacitors I'm fairly confident it's indeed the MAX8969.


A working spare will reveal what output voltage was used, but I'm willing to hazard a guess it's the 5.0V version.

[fzabkar]

https://datasheets.maximintegrated.com/en/ds/MAX8969.pdf

That chip's maximum output is only 6V, yet you are measuring 30V at that point. :-?

Edit: This web site agrees with your choice:

https://www.firstxw.com/view/235586.html

So does this one:

https://gbatemp.net/threads/switch-no-backlight-and-cracked-chip.592312/


I found one site selling an MAX8969EWL50+ with a marking code of +AJZ. That's the 5.0V version.