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Selection Guide2026-08-09 · 6 min read

Power Inductors for Power Supplies: Spec Guide

Quick AnswerA power inductor is specified by inductance at rated current, saturation current, DCR, core loss at the switching frequency, temperature rise and footprint. Material choice follows current and frequency: FeNi powder cores (Bs ≥1.5 T) for high-current stages, ferrite for low-power high-frequency stages, Sendust/MPP for filters. Give the manufacturer the full operating profile — not just the nominal inductance — to get a part that survives worst case.

Power inductors look simple — a core and a winding — but the difference between a reliable part and a field failure is in the specification. This guide lists the parameters that matter and the RFQ data a manufacturer needs to quote correctly.

1. The specification parameters

ParameterWhy it matters
Inductance (µH)Sets ripple and current-mode stability; check at rated current, not at zero
Saturation current (Isat)Inductance must hold at peak current with margin
DCR (mΩ)Sets copper loss and efficiency; drops with size, rises with turns
Core loss @ f, ΔBThe frequency-dependent term that decides temperature rise
Temperature riseHot-spot limit vs ambient and insulation class
Size / heightBoard density and thermal path constraints

2. Material by operating point

High-current stages (AI GPU VRM, server POL, EV chargers) need a core with high saturation: FeNi powder with Bs ≥1.5 T keeps the part small and inductance stable under bias. Low-power high-frequency stages favor MnZn ferrite for low loss and cost. Filters and PFC use Sendust or MPP; MHz power delivery uses molded metal inductors (0.047–6.8 µH, 1–100 MHz).

3. Core loss is the frequency-dependent trap

Datasheet loss values are quoted at specific frequencies and flux swings. The real design operates at your PWM frequency with a triangular ripple — ask for loss data at your exact frequency and ripple ratio, and derate for the hottest ambient.

4. RFQ checklist for a power inductor manufacturer

  • Inductance tolerance and the current at which it is measured
  • Rated DC current and peak transient current
  • Switching frequency and ripple current waveform
  • Ambient temperature range and allowed temperature rise
  • Footprint, height and termination (SMD/through-hole) constraints
  • Target efficiency or DCR limit, and any qualification standard (e.g., AEC-Q200)

With a complete profile, a manufacturer can size the core and winding correctly the first time. The High Flux Cores Guide shows the YTFN series specifications, and the Core Selection Guide walks through the material decision.

YUTE Magnetics manufactures custom power inductors with IATF 16949 and AEC-Q200 qualification. Send the checklist above through the engineering RFQ and get a technical evaluation within 24 hours.

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