This Richtek application note explains various inductor types, core materials, electrical characteristics, and selection guidelines for power converters.
The note introduces the importance of inductors in switch‑mode power supplies and describes the different core materials—ceramic, ferrite, and powder—along with their impact on inductance, impedance, saturation current, and losses. It also covers how package structures such as wire‑wound, multilayer, and molded affect EMI and magnetic coupling.
Practical design examples show how to calculate inductance, choose appropriate core materials, and evaluate key parameters like inductance tolerance (±20% M or ±30% N), Q‑factor, rated current (IDC), and saturation current (ISAT). Comparative tables of common inductors illustrate performance trade‑offs among core types and package styles. This manual is written in Chinese.
| Inductance tolerance | ±20% (M) or ±30% (N) |
|---|
The primary core materials are ceramic, ferrite, and metallic powder (powder) cores.
Standard inductors usually have a tolerance of ±20% (M) or ±30% (N).
Molded (冲压式) inductors have the smallest leakage field compared to non‑shielded, semi‑shielded, or shielded designs.