Is the thermal pad of the L5150BNTR electrically connected internally to Pin 2 of the SOT-223 package?

[ESant.3]

I know I could take a meter and simply check but I don't have any spare parts easily accessible to make this quick measurement.

[Peter BENSCH · Accepted solution]

Welcome, @ESant.3​, to the community!

If by thermal pad you mean pin 4 from the data sheet, figure 21, then this pin is connected to pin 2 (GND). You can also see this in the data sheet on page 1, where both pins are marked with "2", i.e. the same potential. ;)

If the problem is solved, please mark this thread as answered by selecting Select as best, as also explained here. This will help other users find that answer faster.

Regards

/Peter

[ESant.3]

@Peter BENSCH​ Thank you for your response, but this is in conflict with a direct case/ticket I put in to ST Customer support. This was Customer Support response: "To answer the question about the thermal pad, if its not specifically called out as a "connection" in the datasheet, then its floating internally (as most are). I just double checked the L5150 and that is the case. In other words, its not electrically connected. However for best thermal considerations, it is a good rule of thumb for it to be soldered to a large thermal/copper plane on the PCB which is typically a ground, but again it’s not electrically connected or required."

Is ST asserting now that it is connected internally?

[Peter BENSCH]

You refer to ticket # 00177888, right?

Well, for me the data sheet is crucial and the most important source of information. There, as I mentioned, the fourth pin is marked as pin 2, from which I conclude that pin 4 and pin 2 (GND) are connected.

If Customer Support claims otherwise, you'd best check it yourself, because I don't currently have an L5150BN to measure.

[ESant.3]

@Peter BENSCH​ Winner! Peter is right, L5150BN Pin 2 is internally connected to the thermal tab/pin/pad in the SOT-223 package. Had to lift a pin on a production assembly, but worth it to get the answer.