Ferrite beads (or chips) are recommended for IDT clock products for power supply filtering of the main supply rails. The five leading parameters and characteristics to consider when selecting ferrite bead are DC resistance, AC impedance, bias current rating, material, and package size. What is desired for good isolation is a low pass power filter. For that a bead with some DC resistance is best. High current power beads should be avoided. How much resistance depends on how much voltage drop is allowed and therefore the maximum current of the device being powered. Refer to application note AN-805 for more details. For questions not answered by the Knowledge Base, please submit a technical support request.