LMQ66430: Return current path control

Bruce Walter

Part Number: LMQ66430

Tool/software:

I am using the LMQ66430 in many new application and I like it a lot.

I have a question about separating the low-side MOFET current from the heat dissipation paths. Referencing the Data Sheet and SNVA721A.

The Data Sheet implies pin 6 is where this low-side MOSFET current flows, and the DAP, while GND, is for heat dissipation, not a current path. Yet the Data Sheet layout example shows a connection from DAP to pin 6, as well as NC pin 9, possible just to provide a return path for the RFBB, VCC decoupling and RT.

I am concerned about some of the low-side MOSFET current going through the DAP VIA to the GND plane and finding another less desirable return path.

Can I have the DAP ONLY connect to the GND plane for heat dissipation, use pin 6 for current path control, and provide another return path for RFBB, VCC and RT?

2 months ago

0 Pramanik Patel 2 months ago

TI__Expert 4395 points

Hi,

I would say that, you need not worry about the another less desirable return path, at the end of the day, PGND will go to the GND of the whole system and so the RFBB, VCC decupling and RT will also be grounded to GND which in turn is PGND. Let me know if you are able to get my point or not, I would be glad to help you out.

Thanks,

Pramanik Patel

0 Bruce Walter 2 months ago in reply to Pramanik Patel

Prodigy 10 points

Just wanted to make sure there was no current through DAP so I can electrically isolate it for thermal coupling. Thanks.

0 Pramanik Patel 2 months ago in reply to Bruce Walter

TI__Expert 4395 points

Hi,

I am glad that I was able to help you.

Thanks

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LMQ66430: Return current path control