> On Tue, Dec 16, 2008 at 6:17 PM, Harold Hallikainen > wrote: >> I'm using an LT3461A in a small flyback converter running at 3MHz. The >> high frequency was chosen to stay away from an RF receiver frequency >> (lower frequency switchers have harmonics that land on or close to the >> frequency I'm trying to receive). Does anyone know of a transformer >> similar to the Coiltronics VP2-0216R that operates well at 3MHz? This >> part >> is rated as "above 1MHz," but I don't think they had 3 in mind. It has 6 >> windings, each around 10uH. >> >> Thanks! >> >> Harold > > 3MHz is very high. If I were in your position I would ask an apps. > engineer at Coilcraft, Arnold Magnetics, and Magnetics Inc. > > What's the RF frequency you are trying to avoid, and why does a higher > frequency help avoid interference? Do you need a flyback because of > multiple output voltages? If you can't make this run at 3MHz perhaps > you can use a soft switching ZVS or ZCS supply which would produce > less RFI. > > - > ML Thanks! I have an inquiry in with Coilcraft. The existing transformer seems to be working ok at 3MHz, but I'd like to see if there's a better fit. I'm receiving 1.8MHz and using an IF of 10.7MHz. I'd like harmonics of the switch frequency to miss these. Yes, I need two voltages, so that's why I'm using flyback instead of just boost. I need 14V and 3.3V. This is running off batteries, currently 3 NiMH. Thanks! Harold -- FCC Rules Updated Daily at http://www.hallikainen.com - Advertising opportunities available! -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist