A Lateral MOSFET Power Amplifier Design Version 1.1

[Indiglo]

At 50vdc there should be a minimum of 0.6mm between the +/- power supply rails to ground.
As an example a 2oz 5mm track width at a 22 degrees temp rise is rated at approx 8.7amps (subject to other PCB parameters).

Saturn PCB Design have a nice free PCB software tool that has all these calculations - https://saturnpcb.com/saturn-pcb-toolkit/

 

[kapitiaudio]

1.2 mm would be the minimum spacing assuming standard PCB material without a conformal coating.

 

[Indiglo]

Actually after updating to the latest pcb tools version the minimum spacing comes out to -
31-50v - uncoated below 3050metres = 0.64mm
51-100v - uncoated below 3050metres = 0.64mm

31-50v - uncoated above 3050metres = 0.64mm
51-100v - uncoated above 3050metres = 1.50mm

 

[Mark Tillotson]

In the post #35 above, even with the large traces, isn't it true that the thinnest section of a trace is the funnel for high current?

High current density perhaps. Current in a series circuit is the same everywhere. And high current density means higher stray inductance as well as self-heating.