Depends; I had one application where the metal body of the unit was accessible and worked rather well as a heat sink! So heat sinks don't necessarily cost anything (Drilling that 1/4" stainless piece was a bear, OTOH ) For a linear I'd at least put in a series power resistor to drop the input voltage to say 9 or 10V at 1A 'full-bore' draw, that'd reduce your regulators' heat sinking requirements to about 5W or so (30V in so 20V drop, at 1A means 20 ohms, 20 watts gets dissipated across that resistor. May have to bolt that resistor to a heat sink to keep it from melting ) Switchers are good for high voltage to low voltage conversions, definitely. The inductors are 'a pain' IMO though. Mark Wagner Lipnharski wrote: > Are you talking about a linear voltage regulator that will dissipate 25 > Watts??? You should go for a switching step down regulator... lots of > space and power savings. Just the 25W heat sink would cost more than the > switching parts. > > The LM2936 can ouputs a max of 50mA, 40V max input, it means at the > limit it will dissipate less than 2Watts. > > Jameel Ahed wrote: > > > > Has anyone found a 5V Voltage regulator with an output of approximately 1A.. > > that can handle a 30+ Volt input? > > Jameel > > > > ----- Original Message ----- > > From: Jim Hartmann > > To: > > Sent: Thursday, February 10, 2000 8:26 AM > > Subject: Re: low-loss voltage reg [OT?] > > > > > Another chip that looks nice is the National LM2936: LDO, 5V out, 40V max > > > in, 15ua quiescent @ 100uA out. > > > -- I re-ship for small US & overseas businesses, world-wide. (For private individuals at cost; ask.)