Originally Posted by
enine
They do, look up the powertrends stuff. $$$ though. A simple three terminal LM340t-5 and -12 wold be fine.
Careful with linear regulators in this application. 48V down to 5V is a 43V drop, even a small current will produce a significant amount of heat (and wasted power). There are switching modules designed as drop in replacements for linear regulators:
V78XX-1000 Series Very ez to use, but not cheap. Although if you look at the parts to do it yourself using a simple switcher... it probably all works out in the wash especially if you don't have access to free components.