I'm trying to obtain 5V DC from a 37V DC power supply. The load is a computer fan that at 5V drains 31mA (around 0.15W). I'm using a LM350 voltage regulator (LM350 Datasheet). I get a very precise 5V output but the chip becomes really hot. I measured that the the power supply provides 49mA at 37V. I think that the LM370 use 48mA - 31mA = 17mA, so it dissipates 37V * 17mA = 0.63W. (Please correct me if these calculations are wrong) It bothers me that the voltage regulator requires more energy than the load. It's normal or I'm doing this in a stupid way? There is a better way to supply a computer fan from a 37V DC tension?
P.s. On the datasheet it says that the maximum input-output voltage differential is 35V. I'm using it with a 32V voltage differential. Is it safe? I need a better voltage regulator?