This brings up a question I have been meaning to ask here - I have been looking for a Switching Regulator which will replace a 7805 product in a TO-200 package. It's not that I need the full 1Amp output - I do need to drop 12V to 24V down to 5V to power a card which will pull about 150mA MAX. Worst case is dropping 19volts @ 150mA which is 2.85 Watts - that's a lot of power to throw away to get 0.75 watts. The board was designed with a TO-220 standing up and thus taking very little PCB realestate. While there are small switching regulators which will do this, they are invariably in DIP packages. There is simply no way to get a 16-pin DIP in the place of a TO-220. Has anyone seen such a device? A switcher in a TO-200 which can deliver 5.0 volts @ 150mA from 12V - 24V? It certainly seems like a product many people would have a use for. RJG ----- Original Message ----- From: "michael brown" To: "Microcontroller discussion list - Public." Sent: Sunday, December 19, 2004 1:53 PM Subject: Re: [EE:] Is this going to die? > John Pearson wrote: > > I have a 5v voltage regulator where the data sheet states the > > absolute maximum input voltage is 9v DC. I want to use transistor > > batteries on it and the voltage that the regulator sees on the input > > side, with the full circuit operating, with a new battery, is about > > 9.2 - 9.3 volts. > > > > I don't want to slip-in a diode because I want to get the maximum > > life out of the battery without a voltage drop penalty. > > > > What do you think. Am I looking for trouble? > > Tell us how much current you need to draw. Unless you need the 9V for > something else in the circuit, you are going to waste nearly half of > your usable battery by heating the regulator. Perhaps you could use a > low dropout regulator and 4 or 5 AA's or AAA's. Or design the circuit > to run at lower voltages (if possible) and skip the regulator all > together. Maybe a switching regulator would be worthwhile considering? > > _______________________________________________ > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist _______________________________________________ http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist