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TPS73233 pcb layout: GND input and GND output

I'm going to use TPS73233 to supply a GPS module.

The microcontroller connected to this GPS module (uart connection) is supplied from another LDO.

TPS73233 datasheet suggest to use two different gnd plane, one plane for input and one for output section, connected together on LDO gnd pin, to improve PSRR.

Which will be the 'current return path' of uart lines?
If the only conjunction point of ground will be the LDO gnd pin, 'current return path' risks to be a bit long.

Is there any trick to obtain shorter current path return? (also for higher current or higher frequency). Or this is not a real noticeable problem?

  • Hi Stefano,

    You will need to size the return path for your application's current requirements.

    The idea of a star ground is to minimize the possibility of coupling through the ground plane by minimizing the ground connection between the input and output capacitors. The size of the connection between the two planes will be application specific based on the current requirements in the application.

    This is not a requirement for the device to operate, just a recommendation to improve PSRR.

    Very Respectfully,
    Ryan