18v 5v psu
Thanks for the fast replies!
I dont need much current, just to drive a couple of chips and an lcd. I'll chuck a small heatsink on the regulators anyway just to be safe. I do need to run the USART on an ATMEGA16 which I've heard needs a bit of extra oomph, anyone know how much? I'm sure it's in the data sheet, ill have a look later on.
I'm not keen on a switching supply because i need a super clean 5V for the ADC in an avr micro. I've been driven totally nuts by noise already, so i dont want to introduce even more.. So i'd prefer to stick with the good old regulators.
Do you think i should go with feeding the regulated 18V into the 5V regulator? and a 13V drop wont cause heat problems at low currents? Would it be best to feed the regulated 18V into the second reg, or simply feed it straight from the unregulated voltage.
Thanks again
Sam