OPA4191: Connect the Thermal Pad

Hi Reiner,

The exposed thermal pad of OPA4191 16-Pin WQFN package must be soldered directly to PCB for thermal and mechanical performance BUT it does not have to be electrically biased - see below.

If I want to put the thermal pad on a potential. Which potential do I have to use?

The thermal pad must be connected to the negative supply (V-) ONLY in the case where it is internally connected to the die substrate.

However, in the case of OPA4191 WQFN package, there is no such internal connection - thus the thermal pad floats. This allows connecting the thermal pad to any potential within the supply voltage including PCB ground plane (mid-supply) in order to achieve best thermal heat sinking performance.

We had connected the thermal pad to GND. This led to the defect of the OPA4191 in the WQFN package. In the meantime I found an article in the support where it is written that the thermal pad is connected to V-.

OPA4191: OPA4191IRUMR Thermal Pad Connection - Amplifiers forum - Amplifiers - TI E2E support forums

Thus, it looks like the thermal pad of OPA4191 WQFN package is in fact internally connected to the negative supply despite there is no mention of this in the datasheet.  In this case, you may only leave it floating or connect it to (V-).  Sorry for the confusion. 

Please include this important information in the data sheet

Yes, I have passed the missing info to the team responsible for our datasheets.