recently I smoked a esc on the #2 motor on my Darwin F4 AIO.  As we all know that pretty much makes the AIO totaled, well maybe Darwin got their poop in a group with this one.  Yes, it is not the best, lightest, blah, blah blah...  and as a matter of fact the USB connector was failing.  Im guessing from the crashing, it was exposed on the outside on my tinyhawk freakstyle.  
  If anyone has read any thing I have posted, its pretty evident IM CHEAP.  I do not have deep pockets, and try to get the most out of what ever I have.  Case in point,  this AIO, would respond to BF with a little pressure on the USB so I can use it for bench work... I looked at the stack real close and it looked as though it was only held together with a few solder joints on each end. I decided to try to resolder the USB contacts back to the FC, but the ESC was covering them.... well, I had nothing to loose.  took  my exacto bladeput some pressure between the boards and heated the battery lead pads..POP,,, well there is one side... added flux and solder to the other  end.... and it just seperated, just that easy.   
  the USB repair was real easy, removed the old solder, cleaned the pads (they were all intact), resoldered them... and its all good,  The breakout pads are all on the one end the other battery pads only feed to the esc.  So now I have a FC I can use.  well for a 1-3s build... but hey its better than loosing the whole thing.  Darwin does offer a ESC for $20, I may order it and give it a shot....

Assuming you can read the numbers on some of the unburned MOSFETs, get on AliExpress and order some replacements of the same type for a couple of dollars, then just get your hot air rework station out and replace any burned FETs. That will then save the ESC too 

If you can’t read them, let me know and I’ll get you a nice picture of a mosfet from my darwinfpv 15A aio board.

im willing to give it a shot.. im scared that if i get the components hot, i will accidently move more than the the mosphets. I have a hot air station, it came with the repair station I got from cyclonefpv and have been waiting to cook something.
mosfet says 025X23 X2010.. got nothing to loose.

did a quick search, no luck, Darwin comes up, Ali express also.. but nothing matching these numbers, is there a cross reference? can other mosfets fit/work?

(31-Jan-2023, 01:15 PM)Rob Axel Wrote:  did a quick search,  no luck, Darwin comes up, Ali express also.. but nothing matching these numbers,  is there a cross reference? can other mosfets fit/work?

It looks like you might be out of luck. Your best bet will probably be to contact DarwinFPV support and ask if they can provide you with a datasheet so you can then try to source some compatible alternatives.

I reached out to DarwinFPV to find out (I’d like to be able to keep my own board in the air if an esc dies) and the response I received was:

“The mosfet of this AIO is our official customization, and it cannot be bought outside.”

I asked if they’ll sell just the mosfets, I’m still waiting to hear back.

…but it’s looking like the only way to keep these in the air is with donor boards.

I asked ChatGPT what it knew about MOSFETs with a 025X23 marking on them but unfortunately it drew a blank like us and just came back with a generic response that ended with a suggestion of looking at the manufacturer's datasheet. I guess it was worth a try

I don't understand why such a small company like DarwinFPV have had a bespoke MOSFET commissioned that isn't available to buy off-the-shelf. All I can think of is that there are no other 15A MOSFETs already out there in the same package size, but that then puts them in the same category as Apple from an anti-right-to-repair perspective.

If they won't sell you replacements, ask them if they will provide the datasheet instead. At least then you have some kind of fighting chance of trying and find an alternative.

What are the external dimensions of one of those 025X23 MOSFETs?


ChatGPT dialogue:

Wow, you went further than I would have … well, this is a perfect Example of why I keep old components.. I have a new Darwin AIO in the quad.. and IF the esc smokes a mosfet.. I’ll give it a shot.

I heard back from DarwinFPV.
I gotta say, it is nice to have a manufacturer that is so responsive.

They will sell individual mosfets.
They’ll charge USD $0.50 per mosfet, plus a $6.99 shipping charge.

You have to contact them directly to purchase mosfets. They will combine shipping if you purchase anything else from them- so for example, if you order a new AIO board directly from them, they will just toss the mosfets in the package for $0.50 each with no additional shipping cost.

They don’t have a datasheet that they will or are willing to share, but 50 cents a mosfet is probably cheaper than you’ll be able to find a suitable substitute.

(02-Feb-2023, 04:51 AM)Lemonyleprosy Wrote: They will sell individual mosfets.
They’ll charge USD $0.50 per mosfet, plus a $6.99 shipping charge.

You have to contact them directly to purchase mosfets. They will combine shipping if you purchase anything else from them- so for example, if you order a new AIO board directly from them, they will just toss the mosfets in the package for $0.50 each with no additional shipping cost.

They don’t have a datasheet that they will or are willing to share, but 50 cents a mosfet is probably cheaper than you’ll be able to find a suitable substitute.

The cost is a bit steep with shipping if all you need is a few MOSFETs. It sort of forces you to buy other stuff from them at the same time to justify the shipping expense.

I ordered a strip of 10x Alpha & Omega AON7934 MOSFETs from AliExpress last week for $3.67 with shipping to go on an HGLRC ESC. Maybe you could use these on the DarwinFPV ESC although they do have a lower rating of 13A compared to 15A of the ones on the DarwinFPV ESC so it would depend on what motors and props you are using. The package type is going to be the biggest constraint because they would need to match what is already on the DarwinFPV ESC and you won't know that until you can get one off the board. The AON7934 MOSFETs use a DFN3x3A package which is a specific size with a specific pin / conductor layout on the bottom as shown in the image below...

For future reference in case DarwinFPV stops supplying these:

Dual Channel.

External dimensions:
2.5mm x 3mm (my calipers are not super accurate- but they are rectangular not square.)

I'll try to make some time to take some measurements on one of these at some point, but here's some physical sizes at least:

It looks like the pin spacing is the same as the AON7934 MOSFETs and the overall size is within 0.5mm. Looking at the Darwin F4 AIO ESC there looks to be enough of a gap between each MOSFET to squeeze another 0.25mm length on each of the sides and still have a gap. The underside is a little different but there is no reason the single larger base pad on the AON7934 can't just span the two solder pads on the ESC board.

So AON7934 MOSFETs could be a possible off-the-shelf alternative if you are happy with a lower current rating. You might also have to replace all the MOSFETs for consistency across the board and to avoid any oddities. 12x AON7934's would set you back around $5 but the work required to replace them all might not be worth the hassle, and then it might not work as expected afterwards anyway. So maybe you're just better off just shelling out $0.50 each plus shipping for the proper replacements from DarwinFPV. It's unfortunate but that's the way it seems to be.

If you check the footprint of the AON7934 I think you will find that it won't work. The gate pins are on opposite sides of the mosfet, and the mosfet Lemonyleprosy has pulled off has the gate pins on the same side, at least from what I can tell. I am no expert by any means but I'm pretty sure the AON7934 does not have a compatible pin configuration with the one Lemonyleprosy photographed.

From the AON7934 datasheet I found:

…man you guys are WAYYYYY OVER my head!!

(16-Feb-2023, 08:36 PM)Mike C Wrote: If you check the footprint of the AON7934 I think you will find that it won't work. The gate pins are on opposite sides of the mosfet, and the mosfet Lemonyleprosy has pulled off has the gate pins on the same side, at least from what I can tell. I am no expert by any means but I'm pretty sure the AON7934 does not have a compatible pin configuration with the one Lemonyleprosy photographed.

From the AON7934 datasheet I found:

Yeah, it looks like the AON7934 is using an alternate pinout and footprint compared to what most specs state for a DFN3x3A IC. So it's not going to work.