Inverting buck converter GND plane

[beenz]

Hello, I am working on a multi-channel test equipment that requires dual +/- 15 V rails.

I have decided to use the LT8645S buck IC to generate both voltages. Since I have never used such an IC in an inverting configuration (see picture) I am wondering how to design the ground plane in such a situation.
What is the recommended best practice? I was thinking of following the guidelines given in the datasheet, which would mean that for that part of the circuit the GND plane is actually going to be a VEE plane.

[beenz]

image did not get uploaded apparently

[thm_w]

You can still use a GND plane, but since so much is connected to VEE, you'd probably have a plane or pour for that as well.

https://www.ti.com/lit/ta/ssztau6/ssztau6.pdf?ts=1765318704607

https://www.infineon.com/assets/row/public/documents/24/42/infineon-dc-dc-converter-configuration-of-inverting-buck-boost-using-ir3889-buck-regulator-applicationnotes-en.pdf?fileId=8ac78c8c8a44f57b018a617cdc9d51cd

https://www.ti.com/lit/an/slyt286/slyt286.pdf?ts=1765275549616

https://www.analog.com/en/resources/design-notes/making-a-voltage-inverter-from-a-buck-stepdown-dcdc-converter.html

[beenz]

I was aware of some of the app notes already, but I hadn't found the one from TI with the layout recommendations. I sure wouldn't have thought of placing the input and output capacitors in the way it's mentioned in the paper, so thank you very much