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

ESant.3
Associate II

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.

1 ACCEPTED SOLUTION

Accepted Solutions
Peter BENSCH
ST Employee

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

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.

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4 REPLIES 4
Peter BENSCH
ST Employee

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

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.
ESant.3
Associate II

@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?

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.

In order to give better visibility on the answered topics, please click on Accept as Solution on the reply which solved your issue or answered your question.
ESant.3
Associate II

@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.