Different versions of FQP17P06 mosfet

Thread Starter

Gamerboi28

Joined Nov 29, 2023
3
What does the number at the top of these two mosfets mean? I figured this might be different batches or production line, as one has the fairchild logo and the other the onsemi logo, which makes me think the second one was produced after the companies merged.

For context, they are both used in the same circuit, but the ones with the onsemi chip doesn't work as intended, while the fairchild version is functional and we've been using it for its intended purpose. Between these two circuits, the only difference we've found is the number at the top, would it have any impact on the functionnality of the mosfet?

Thank you

The numbers in question are 1K19CB (Fairchild version) and 1P15AA (OnSemi), in case the pictures aren't clear enough.
 

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Thread Starter

Gamerboi28

Joined Nov 29, 2023
3
In what way doesn't it work?
Well I'm not so sure, as I frankly don't understand how the circuit really works. It was designed by a friend of someone who used to work with us, and I haven't even been able to find the PCB design files. All that I know is that we usually have a flip switch that turns off our device, and it doesn't work on the circuits with the onsemi chips. We've compared the circuits that work with the ones that don't and the only difference seems to be in this code.

The other problem is this chip seems to be discontinued, so there is no way to order a new one and compare with those. With my current knowledge of electronics, I don't really know how to compare different mosfets and why this one specifically was chose for the circuit. If anyone knows of a different chip that could replace it, all suggestions are welcome.
 

Ian0

Joined Aug 7, 2020
9,499
Well I'm not so sure, as I frankly don't understand how the circuit really works. It was designed by a friend of someone who used to work with us, and I haven't even been able to find the PCB design files. All that I know is that we usually have a flip switch that turns off our device, and it doesn't work on the circuits with the onsemi chips. We've compared the circuits that work with the ones that don't and the only difference seems to be in this code.

The other problem is this chip seems to be discontinued, so there is no way to order a new one and compare with those. With my current knowledge of electronics, I don't really know how to compare different mosfets and why this one specifically was chose for the circuit. If anyone knows of a different chip that could replace it, all suggestions are welcome.
It's a very ordinary P-channel MOSFET. There will be scores of alternatives.
Why don't you post the circuit to see if someone can spot any flaws that would make operation critical on certain parameters.
Or did you get some fake parts? Check to see if they are N-channel. N-channel devices are cheaper and are marked up to sell as fakes of all sorts of things.
 

Papabravo

Joined Feb 24, 2006
20,994
Well I'm not so sure, as I frankly don't understand how the circuit really works. It was designed by a friend of someone who used to work with us, and I haven't even been able to find the PCB design files. All that I know is that we usually have a flip switch that turns off our device, and it doesn't work on the circuits with the onsemi chips. We've compared the circuits that work with the ones that don't and the only difference seems to be in this code.

The other problem is this chip seems to be discontinued, so there is no way to order a new one and compare with those. With my current knowledge of electronics, I don't really know how to compare different mosfets and why this one specifically was chose for the circuit. If anyone knows of a different chip that could replace it, all suggestions are welcome.
We would need a schematic diagram of the board it is supposed to go in. Recommending a substitute without an understanding of the circuit is fraught with peril. You may have to look on the gray market for availability.
 

Thread Starter

Gamerboi28

Joined Nov 29, 2023
3
It's a very ordinary P-channel MOSFET. There will be scores of alternatives.
Why don't you post the circuit to see if someone can spot any flaws that would make operation critical on certain parameters.
Or did you get some fake parts? Check to see if they are N-channel. N-channel devices are cheaper and are marked up to sell as fakes of all sorts of things.
As I said before, I don't have access to the schematics, so I can't really post it here. As to the fake parts, that would be possible as this specific batch was ordered from AliExpress instead of Digikey. Digikey seems to refer similar parts to this one, so I think my best bet would be to order those and try them out.
 

Papabravo

Joined Feb 24, 2006
20,994
As I said before, I don't have access to the schematics, so I can't really post it here. As to the fake parts, that would be possible as this specific batch was ordered from AliExpress instead of Digikey. Digikey seems to refer similar parts to this one, so I think my best bet would be to order those and try them out.
You approach may be successful, but I hope there is a minimal economic penalty for not finding an acceptable solution. I do know that many people avoid AliExpress like the plague because of situations like this.

My next best suggestion is to look at the datasheets and setup a test jig to characterize the parts that you have. Does your company have components engineer? Sounds like it might need one.
 

BobTPH

Joined Jun 5, 2013
8,662
Digikey seems to refer similar parts to this one, so I think my best bet would be to order those and try them out.
Yes, buy from a reputable dealer. Looks like you have been had. I am willing to bet those parts are not as marked, or were factory rejects that they somehow got hold of.
 
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