At 02:28 PM 5/14/99 -0400, you wrote: >Anybody know of a SMT regulator which can handle 45V input, 5V/50mA output? > 40V * 50mA = 2W - an awful lot for a tiny PCB to handle. > >I'm finding very few options in the datasheets. > >PCB size is a premium. Reliability is SUPER important, component >cost/complexity is secondary. > Check with National Semi. They have variants of the 78xx series in a "DPAK" configuration. Gets over 30 volts on the inputs, but I don't recall how far over. Unless you need a really WIDE input range, put a power zener in series to drop the voltage to an acceptable level. A 30 volt .05 A zener would need to be 2 watts and would drop your 40 volts to 15 which most SMT devices will handle (16 volt MAX). A note to everyone: Check out the TELCOM TC55 series! 200 mA output, 3 microamps quiescent current, VERY low dropout voltage, and CHEAP. SOT-23 package. We plan on buying a reel of 5 and 3.3 volt parts and would consider selling in smaller quantities. This is a really good part! **************************************************************************** ******** All legitimate attachments to this email will be clearly identified in the text. Please note our new address and phone numbers. William K. Borsum, P.E. DASCOR P.O.Box 462885 Escondido, CA 92046-2885 V&M&F) 760-796-7785 Direct) 760-796-7788