A power inductor often has more than one current rating. These are not duplicates: one limit describes loss of inductance through core saturation, while another describes heating from losses. Either can limit the design.
Check these eight points
- Inductance: use the value required by the design or controller documentation, including tolerance.
- Peak current: compare maximum inductor current, not only average output current.
- Isat: read how much inductance drop the manufacturer uses to define this rating.
- Irms: check the temperature rise and test conditions behind the rating.
- DCR: winding resistance causes loss and voltage drop; include its temperature dependence.
- AC loss and frequency: core and winding loss depend on ripple and switching frequency.
- Shielding and size: assess stray field, height, footprint and mounting.
- Temperature: combine ambient temperature, self-heating and the permitted component temperature.
Manufacturers may define Isat and Irms with different criteria. Compare the datasheet curves for inductance and temperature versus current, rather than only the headline rating.
Define topology, inductance, peak and RMS current, frequency, ripple and ambient conditions. Then view power inductors and verify the exact datasheet, dimensions and thermal behaviour.