TPS53647: Layout question: Analog Ground?

Mark Guastaferro

Part Number: TPS53647
Other Parts Discussed in Thread: PMP10962

I need a little clarification as to whether it's necessary to have an analog ground for the TPS53647 controller with a single point ground vs simply connecting external component returns to the system ground plane.

The data sheet Layout instructions and the eval board appear to have an analog ground layer that is connected to the power ground at a single point through a 0 ohm resistor.

However, the layout for the 3-phase PMP10962 reference design has some controller components tied to a single point while others tie directly to the ground plane on the top layer. Device thermal pad appears to connect to ground plane on several layers including the top (controller mounted on bottom layer of PMP10962).

over 7 years ago

0 Nancy Zhang over 7 years ago

TI__Mastermind 48160 points

Hi Mark,

Separating AGND and PGND is not required. However, the GND plane underneath the controller should be a quiet area. A quiet area is defined as an area where no power supply switching current is likely to flow. 12Vin copper plane underneath the controller should be avoided and keep>60mil clearance.

Thanks,

Nancy

0 Mark Guastaferro over 7 years ago in reply to Nancy Zhang

TI__Genius 11455 points

Hi Nancy,

Thanks for the quick reply. One question - if there is a ground plane between the top layer with the controller and the 12Vin copper plane, is this enough isolation, or should the 12V plane still be cleared under the controller?

0 Nancy Zhang over 7 years ago in reply to Mark Guastaferro

TI__Mastermind 48160 points

Hi Mark,

It should be enough isolation.

Thanks,

Nancy

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TPS53647: Layout question: Analog Ground?