Molypermalloy (MPP) Cores

MPP cores are very stable relative to flux density, temperature and DC current. They are normally used for inductors and other energy storage applications. MPP cores are normally sold pre-graded to a specific permeability tolerance. This makes them ideally suited to pure inductors, because the precise inductance will be known before winding, allowing suitable adjustments to be made to the number of turns, if required. MPP cores are also widely used for energy storage inductors due to their low inductance swing when DC bias is applied. The lower permeability MPP cores can be used at frequencies above 500KHz. As the permeability of the core increases, stability tends to decrease. The most popular MPP permeabilities are in the 60 to 173 range, where all the advantages of the MPP product are most apparent. MPP has the advantage of having constant permeability as the flux density varies up to about 3500 gauss. Above this level, permeability does tend to drop off. Other powdered core materials, such as Iron Powder, have permeability that varies with flux, adding to the potential instability of the device. Relative Cost - High

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