Question on PCB and routing

[Jonathan]

Thanks MC very much appreciated, I’d like to think of this project as evolving so adding things to make it better is exactly right

I have some 220 uF 25v Low ESR 8mm dia x 15 mm high 3.5 mm LS ( UPW1E221MPD) from a project also some Panasonic small-form but not sure what stats

They would be fine - you don't need anything special like low ESR, but no problem using them. Still need ceramic capacitors on the input.

What voltage are you supplying to the 5V regulators and at what current?

[Fivetide]

They would be fine - you don't need anything special like low ESR, but no problem using them. Still need ceramic capacitors on the input.

What voltage are you supplying to the 5V regulators and at what current?

The idea is to drop 7.2 v to a 5 v 1 amp and the other is 7.2 to 5 v 1.5 amp...the first feeds the raspberry pi the 2nd a USB hub

[Jonathan]

Ok, so you have (7.2-5)*1.5=3.3W dissipated by the regulator... you'll need a heatsink on that. The datasheet for your regulator (link?) should specify the junction to case thermal resistance which you can use to find the required size of heatsink, which may well require making more room on the circuit board.

[Fivetide]

What Ian said is that the regulator has a low thermal output , I don’t know Reg one

[m_c]

justanothefpissedoffuser

[Jonathan]

Oh so they're switching, not linear, regulators - disregard what I said about the power dissipation then as that's irrelevant. I'd still use some small capacitors though.

You're pushing your luck asking for 1.5A from a regulator rated for 1.0A.

[Fivetide]

Oh so they're switching, not linear, regulators - disregard what I said about the power dissipation then as that's irrelevant. I'd still use some small capacitors though.

You're pushing your luck asking for 1.5A from a regulator rated for 1.0A.

Hi Jonathan, yes there are 2 regulators R-785 0-1.0 and R-78B5.0-1.5 the 1 amp is for the Raspi and the 1.5 is for the USB the 1.0 amp has 2 output 2 pin Molex’s, one powers the Pi itself and the other powers Independantly RC-servo controller board for Raspberry PI Version 3

[Jonathan]

Hi Jonathan, yes there are 2 regulators R-785 0-1.0 and R-78B5.0-1.5

Fair enough. They're both labelled as -1.0 on the PCB which was a bit misleading...

Do you really need the high efficiency from these switching regulators? As m_c hinted, you could save a lot of money by using linear regulators and adding heatinks.