Magnetics Powder Cores

Magnetics® Powder Core products, Kool Mu®, MPP, High Flux®, XFLUX®, AmoFlux®, and 75-Series materials, are distributed air gap cores that are primarily used in power inductor applications, specifically in switched-mode power supply (SMPS) output filters, also known as DC inductors. Other power applications include differential inductors, boost inductors, buck inductors, and flyback transformers. Notable characteristics of Magnetics’ Powder Core materials are high resistivity, low hysteresis and eddy current losses and excellent inductance stability under both DC and AC conditions. In addition, Magnetics Powder Core materials are not pressed with an organic binder, therefore, there is no thermal aging.

While all six materials are used in power applications, each has its own advantage:

  • For the lowest loss inductor, MPP material should be used since it has the lowest core loss.
  • For the smallest core size in a DC bias dominated design, High Flux material should be used since it has the highest flux capacity.
  • XFLUX can be a lower cost alternative to High Flux, in situations where the higher core losses and more limited permeability availability of XFLUX is acceptable.
  • Kool Mu (sendust core) is well known for the moderate cost and has significantly lower losses and substantially better thermal properties when compared to powdered iron cores.
  • The combination of high DC bias and low core loss density makes AmoFlux the optimal solution for high efficiency, high power inductors.
  • The relatively high saturation flux density of 75-Series cores makes them a low-cost solution in applications where stable inductance under load is necessary, such as inverters for renewable energy sources and Uninterruptable Power Supplies (UPS).

Five large sizes have been added to the toroid powder core line, including the massive 165 millimeter coreLarge Powder Core toroids are a cost-effective option for high current applications, such as: UPS, large Power Factor Correction (PFC) chokes and inverters for renewable energy. 

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Property Curves

View Powder Core Material Property Curves including Normal Magnetization curves, Core Loss Density curves, Permeability versus Temperature curves, Permeability versus DC Bias curves, Permeability versus AC Flux, and Permeability versus Frequency curves.

View Property Curves

Designing at High Temperatures

Thermal considerations are a basic part of power electronics design. Having this understanding is vital for selecting the best type of material for each application, and for ensuring that the magnetic device will function safely at its maximum operating temperature.

View Design Guide

Powder Core Materials Comparison

  Kool Mu MPP High Flux XFLUX 75-Series
Permeability 14-125 14-550 14-160 26-60 26-60
Core Loss Low Very Low Moderate High Moderate
DC Bias Good Better Best Best Better
Flux Density (Tesla)
1.0 0.75 1.5 1.6 1.5
Temperature (°C)
500 460 500 700 700
Temp. Range (°C)
-55-200 -55-200 -55-200 -55-200 -55-200
60u, u flat to... 900 kHz 2 MHz 1 MHz 500 kHz 500 kHz