NS does have some 1M Hz buck regulator, which can use smaller Ls and Cs. For instance, the LM3102: http://www.national.com/pf//LM/LM3102.html BTW, You don't need a flywheel diode since it has a MOSFET build-in when the main switch is off. Funny N. Au Group Electronics, New Bedford, MA, http://www.AuElectronics.com ----- Original Message ---- From: PicDude To: piclist@mit.edu Sent: Sunday, June 29, 2008 10:31:19 AM Subject: Re: [EE] Switch voltage Regulator - What chip to use? I usually like National Semi's online Webench switcher design tool, as their parts are usually lower cost and requires less support components than Linear. Linear however, seems to have switchers that run at higher freqs, for smaller (and lower-cost) L's and C's, although I recently discovered some newer (to me) parts from National that look promising for my apps -- LM2734, LM2736 etc. I discovered a nice switcher by Semtech some time ago (SC4517), which operates at a high frequency, requires few support components, takes very little PCB space, and is priced quite low. But it's only available in min 1k or 3k quantities IIRC, so I'm evaluating for a redesign of an existing product. Cheers, -Neil. Alan B. Pearce wrote: > >>It needs to handle an input voltage between 20 and 50 volts, supply a >>current of between 30mA and 500mA with an output voltage of 5 volts. > > Personally I like the Linear technology range, but they do not have many > that would handle that input voltage. > > So I would also recommend the MC34063 that Jinx suggested, as a rugged, > well > proven, and available from several sources device. > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > > -- View this message in context: http://www.nabble.com/Switch-voltage-Regulator---What-chip-to-use--tp18107952p18181435.html Sent from the PIC - [EE] mailing list archive at Nabble.com. -- 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