Quote Originally Posted by mister_e View Post
yes, and make sure you have some heat-sink around. Some switching regulator could help. have a look to LM5010
I agree.
The voltages involved can quickly rack-up Watts.
He should keep in mind the heat generated is from the voltage drop within the device, and the amperage through it. With 90 Volts input and 12 Volts output you have considerable voltage differential. The data sheet claims assume you have dealt with the heat, and removed it.

Second pitfall:
Use an input (bypass) capacitor.

Third pitfall:
Mind the "Minimum output current to maintain regulation".

As you said the switching regulator could help. More efficient and a lot less heat to dump. Little more engineering though.

-Adam-