XTR300: Protection XTR300 with 1 TVS3300 or 1 TVS3301 or 2 TVS3300 back to back?

I'm so confused, in another document I've read this configuration:https://www.ti.com/lit/an/slva885/slva885.pdf?ts=1749139784853&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FTVS3300

where the cathodes are opposed, so I would like to be sure which is the best configuration:

1) with cathodes togethers:

2) or with anodes togheters:

thanks for your best support.

1. Hi McKenzie, thanks for your answered, but why in your application note suggest back to back TVS1400? If the power supply is ±15V?
2. I've thought, but I'm not sure to use two hours TVS, one TVS3300 with cathode connected to out loop current, the anode connected to the second abode TVS0500 and it cathode to common ground return loop current. 

What you think? 

Thanks

Hi McKenzie,

thanks for your support.

For the second question I'll try to use and design in my schematic and pcb layout, hope to have a good feedback.

Instead, I've found a mistake in this evaluation board: https://www.ti.com/tool/TIDA-01633 if you open the file schematic https://www.ti.com/lit/df/tidrwn4/tidrwn4.pdf?ts=1749484441402 you can see that the TVS protection are inserted in this mode:

with cathodes togheter and anodes on the AoutCh1 and Ground GND, and I think there is an error, I supposed,

but if you open the file PCB Layout Altium https://www.ti.com/lit/pdf/tidrwn7 I see that the components are inserted in opposed direction than the schematic:

in fact the dot point is the Cathode:

Could you give me a feedback about this? Could you agree?

thanks

best regards.