Help identifying a chip

[quiggy]

Hopefully this is the right place to post this.

I've been searching for days trying to find out what this chip is called. I know what it does but searching to buy a replacement is impossible, could anyone help me in identifying it so I can buy replacements?

It's a driver that powers mosfets on a graphics card and that's all I know about it. Any help would be appreciated I've attached a picture of it.

[momaka]

Re: Help identifying a chip

Afraid I can't help with finding what that chip is (my research for these things is not so good).

That aside, if this chip is for an ATI Radeon HD, R7/9, or RX graphics card with shorted MOSFET(s), don't waste your time - GPU is probably shorted and dead.

[quiggy]

Re: Help identifying a chip

I've been searching for a while. I think it's the fact it has an = sign on the chip that throws off the search results.

It's from a gtx 980, I'm fairly sure the gpu is good but it's not recognised in the pci slot and I'm getting a bad reading from a mosfet. Took the mosfet off and still get the bad reading on just the pad so I'm assuming its the driver for that mosfet thats gone bad but finding one is impossible!

[momaka]

Re: Help identifying a chip

... I'm getting a bad reading from a mosfet. Took the mosfet off and still get the bad reading on just the pad so I'm assuming its the driver for that mosfet thats gone bad

Did you conclude you have a "bad" reading because the MOSFET was showing low resistance from Drain to Source? Or Drain to ground? If so, that is actually normal for certain video card MOSFETs. Reason being the GPU V_core rail usually has a very low resistance to ground - typically 1 to 5 Ohms. Most multimeters will indicate this as a "short-circuit" and make you conclude the MOSFET is bad when in fact it isn't.

So depending on where that MOSFET is located, that may or may not be a normal reading.

Also, a bad MOSFET - be it on the low-side or the high-side of a buck regulator circuit - will typically cause the PSU to crowbar / shut down. The fact that you can start the whole PC without the PSU shutting down means there probably aren't any bad MOSFETs.

To avoid false readings when checking MOSFETs, I only measure resistance to ground and/or to Drain on the MOSFET's Gate. If the resistance is several kOhms or higher, it's probably OK.

[R_J]

Re: Help identifying a chip

That seems to be a Richtek RT9611AGQW Synchronous Rectified Buck MOSFET Driver
02= : Product Code
3B52D YMDNN: Date Code

[quiggy]

Re: Help identifying a chip

Bad reading from drain to ground. But, if I change the mosfet, all readings are fine until I try power it up.

I'll power up the card, my pci post card will give an unrecognised pci-e device code and it won't boot. When I remove the card again and test the new mosfet which was showing as fine prior to powering it up, the mosfet shows as bad again.

I can only conclude that it has to be driver related which is what lead me to those.

Am I right in assuming that provided the replacement driver has 02= printed on it, then it will be the same?

[R_J]

Re: Help identifying a chip

02= should be the RT9611AGQW Did the fets short from drain/source to the gate? if they did check if there are low Ω resistors between the drive ic and the fet's gates. If there are no resistors or they are ok, the ic is likely bad.
Check the pdf file and maybe you can check the ic's output resistance to confirm the ic's output is shorted etc.