A low-dropout regulator won't do anything for you here as you have more=20
than enough overhead voltage.
A 7805 is fine as long as (a) you can heatsink the wasted power away,=20
and (b) you don't need to put the PIC into low-power/sleep mode.
I find that 100mA or maybe even 150mA is fine with a small heatsink,=20
otherwise you'll need a proper heatsink, or a switching regulator would=20
be better.
And in sleep mode, the quiescent current of the 7805 will consume far=20
more than the PIC (IIRC 5-6mA).

Cheers,
-Neil.



On 11/22/2018 10:07 PM, Michael Johnston wrote:
> Happy Thanksgiving Pic guys. I have a project using a PIC16F1847 and it i=
s
> a simple Led tracer application.It will be mounted in a truck and will be
> powered by the 12volt system in the truck. My choice is the 7805 linear
> voltage regulator but My friend told me this was not a good choice for
> automotive applications. I found the TI Lm2940 low drop out voltage
> regulator. I was going to use this but I noticed that Digi Key states thi=
s
> device is out dated and not to use in it in new designs. So does anyone o=
ut
> there know  of a newer low drop out 5 volt regulator for this purpose? An=
y
> help would be appreciated
> Thank You
> Michael Johnston

--=20
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