Chris <chris.rowland@...> wrote:
Do you have a photo?
Try /g/QRPLabs/message/135796 and the other posts in that thread.
Thanks. I see I'm not the only one with concerns...
Interesting that you say that the regulators get "a bit warm" (which I
understand: safe to touch, won't burn you).
I assume there's no magic in using a larger (TO-220) chip vs DPAK with a
large ground plane. The chip inside is similar, the power dissipated is
the same, the heatsinking area is larger with a ground plane than with
TO-220 with a chopped tab. So my ground plane should be actually colder
than your chip, yet it gets to around 80°C, and DPAK (measured at the tab)
to around 90°C...
Of course not immediately. But slowly, steadily, over the course of maybe
minutes, it gets there and settles.
What current draw do you have on your 3V3 rail? Mine is around 100 mA.
BTW, I ran my QMX with these power supplies for 1.5 hour (without a case).
Nothing exploded. So I guess the regulator can handle it. I'm worried
about capacitors -- how long till they fail in this temperature (they're
directly on the ground plane, touching it, actually being pressed to it by
the display)...
I see you're using tantalum ones, maybe I should switch to that as well.
