LM2596T - Double the Regulators Double the Supply Right!?!?

[velvia]

EHLO eevblog.com/forum,
_{Full Disclosure: I know enough to be dangerous but not enough to leave it alone}

I'm in the middle of "solving" a dumb "problem" in a dumb way and wanted to check with the smarts (Y'all) to make sure I'm not going down the wrong path (the path of wasted money and insurance claims). I was looking at the LM2596T Datasheet (https://www.ti.com/lit/ds/symlink/lm2596.pdf) and, best I can tell, I can duct-tape two of them together to get a +/-12V Dual supply from a 20V input.

The github is a mess because of who I am as a person but all the related KiCad files are here: https://github.com/velvia-fifty/AudioThings/tree/main/PSU
_{Please, excuse the inner workings of my brain while taking notes, I have no idea what she's on about either...}

I've also attached incorrectly created PDFs so you don't even have to leave the site for a laugh 

Short story shorter: I'm trying to spin USB PD into ±12V how "directionally correct" am I?

221 Bye,
fifty

[ArdWar]

Yes, you generally can use buck converter as inverting buck-boost. TI have several whitepapers and appnotes on that if you're interested in the finer details of it.

As for your implementation, I guess you're still yet to put the switching diode and inductor for the negative supply?

[Kim Christensen]

I think you've confused 8-3 and the 8-5 examples in the datasheet.

[velvia]

Yes, you generally can use buck converter as inverting buck-boost. TI have several whitepapers and appnotes on that if you're interested in the finer details of it.

As for your implementation, I guess you're still yet to put the switching diode and inductor for the negative supply?

Thanks for the validation.

This was throw together in a fit of insomnia this morning (still going!) so I didn't want to chase rabbits.

This is the rough order of magnitude for overall size right? (if that makes any sense...)

Like, for DC to DC rolling my own*, I can't shrink this down appreciably right? I'm targeting USB PD (so 20V up to 5A) and all I could think was two inputs, but then having to rely on them being different PD adapters.

_{(I know that's an incredibly loaded question full of more questions but I appreciate y'all humoring me)}

*As in hand solderable

I think you've confused 8-3 and the 8-5 examples in the datasheet.

Thanks for the nudge, I assumed that's what I'd want but I'll be honest I don't grok Inductance, like at all so that required a few too many cycles for an "are we sure we can do this"

I went with 8-3 because I was hoping to avoid having COM and GND and potentially having to care about audio grounding later (it's all in my head). Having it all run off PD is worth so much more for what I'm aiming for.

Maybe I'll learn me an inductance or two while I'm banging my head against this for "fun"