Does anyone know of a good set of design guides and equations for designing a planer inductor? The specifications I have are 22 uH (microHenry) with 4 ohm resistance maximum O.D. of 2mm on FR-4. I don't think this is possible but would like the math to prove it. TIA, Jeffrey A. McGlaughlin, C.I.D. Sr. PCB Designer Battelle Memorial Institute Columbus Ohio [log in to unmask]