Help to find out IC reference

[crazynoob]

I was trying to fix a Nvidia GTX 970 graphics card. I found out the problematic chip (DU F4BE), but I can't find the datasheet nor replacement on the internet.
I added a photo of the IC with a red circle around it. Can anyone help me to find information about it?.

[piernov]

Re: Help to find out IC reference

Full model number?
Also how do you know it's the problem if you don't know what it is?

[crazynoob]

Re: Help to find out IC reference

Full model number?
Also how do you know it's the problem if you don't know what it is?

The graphics card is a gigabyte GTX 970 model: GV-N970WF3OC-4GD

I believe this part is causing the problem because I desoldered one from the graphics card and two of the pins are shorted whereas the others ICs do not have that problem.

It seems like it acts as a buck converter controller but I don't know for sure. Those two pins are connected directly to the MOSFET that feed the GPU chip. This short is produced between the gate and the buck converter output (MOSFET drain).

[piernov]

Re: Help to find out IC reference

Yeah these are the MOSFET drivers but I'm not sure what model.
I also can't find any high resolution picture of this card so please post them.
Buck controller is somewhere else, probably a QFN, what are the markings on it?
Also what's the markings of the MOSFETs?

[crazynoob]

Re: Help to find out IC reference

Yeah these are the MOSFET drivers but I'm not sure what model.
I also can't find any high resolution picture of this card so please post them.
Buck controller is somewhere else, probably a QFN, what are the markings on it?
Also what's the markings of the MOSFETs?

I can't get photos with better resolution because I have nothing better than my phone camera. If you need to have a closer look to a certain area just let me know and I will do my best.

The buck controller is a uP1983A.

I tried to draw a rough schematic using the multimeter (CIRCUIT.jpg).

On the photos you will see I desoldered the faulty unknown IC and a bad MOSFET. The MOSFET that is connected to the faulty unknown IC (Shorted) is located on the upper right corner on the photos (K03B7).

[piernov]

Re: Help to find out IC reference

MOSFET drivers are uP1959PDN8 according to
http://www.rom.by/forum/Remont_Gigabyte_GTX_980

[crazynoob]

Re: Help to find out IC reference

MOSFET drivers are uP1959PDN8 according to
http://www.rom.by/forum/Remont_Gigabyte_GTX_980

Thank you so much!! I tought I were gona need to find another GTX 970 (Exactly same model) to repair it. I wonder how did you find it out

[piernov]

Re: Help to find out IC reference

I typed on Google

"uP1983A" "mosfet driver"

there was thankfully one single result that actually gave the answer…

[R_J]

Re: Help to find out IC reference

This site has another picture https://www.modders-inc.com/gigabyte...card-review/3/ with the same part (U4023) marked DU F4A3 so the last two characters are likely date codes But it might be a custom number on the part?

[SMDFlea]

Re: Help to find out IC reference

Here's the data sheet,just to confirm https://pdf1.alldatasheet.com/datash...P1959PDN8.html

UP1959PDN8 Top marking DU