22NY sot23-3 part

General Electronics
#1

Hi,
I have launched a similar question in the kicad forum, but maybe this is a more suitable forum for such an issue.

I need to repair a batch of an obsolete pcb. It has a sot23-3 component marked 22NY.
Does somebody know which part is it?

It seems it is not a transistor nor a diode. Its reference is U while diodes and transistors on the same board are marked as D and Q. And I have read a lot of lists of transistor and diode marking.

I have made searches on the internet with no success.

This is all the information I have. Thanks!

#2

Can you share the schematic. at least the area around this chip?

#3

Thanks, Joseph

I do not have the schematic yet. I will make one based on the pcb.

#4

Thank you very much @ToyBuilder for your help in a private message. I’m sorry I’m not allowed to publish the schematic publicly.

#5

@pedro, You’re welcome. I just sent you another message. I strongly suspect the mystery part is the https://www.mouser.com/datasheet/2/389/stm1061-1851141.pdf

#6

Nice sleuthing, @ToyBuilder! Was it the schematic that tipped you off or something else that led you to this part?

#7

From the schematic and the general description of what it’s supposed to be, I knew what behavior likely made the most sense.

In this case, we needed to check if an input voltage was at a certain voltage in order to enable more circuitry downstream. Like 3-pin linear regulators, 3-pin voltage detectors are made with pre-set voltages, so it seemed likely that the 22 coded for the voltage (2.2v).

Armed with that guess and a few google searches, I tracked down likely detectors in SOT-23. The third datasheet that I looked at looked like a match. (22Nx – but it’s not absolutely sure if the x is a literal x or a placeholder x.) At any rate, I think the device fits the bill for what’s needed in the circuit.

#8

As a matter of fact, I sent a message to ST (no answer yet) with the same question: if the x is a placeholder or a literal.

It is one of the candidates since its reference is not Q or D and all the other 22N parts found in the smd marking tables are transistors.

Thanks again.

#9

Well, Q and D are shorthand for input (D) and output (Q). The pinout certainly fits well with your circuit.

#10

I meant Q for transistor and D for diode.

#11

Oh, heh, yeah. Funny that.

#12

This is part of the schematic, if it can help

22NY-circuit
22NY-circuit968×514 4.23 KB

#13

Finally I have found the part:
stm1061, as @ToyBuilder suggested.
I have found the picture of the 3.4 threshold voltage instead of the 2.2V though.
34NY

Thanks again.