IEC 62025-1:2007

Overview

IEC 62025-1:2007 is an International Electrotechnical Commission (IEC) standard for high frequency inductive components, specifically covering fixed, surface mounted inductors and ferrite beads used in electronic and telecommunication equipment. This Part 1 document establishes non-electrical characteristics, measuring methods, designation rules, recommended standard values and dimensions, and guidance for selection and specification. The 2007 (second) edition introduces updated dimension nomenclature, a new letter code for inductance values, added shape dimensions, and expanded operating temperature ratings.

Key topics and technical requirements

• Scope and object: Defines requirements for fixed, surface-mounted inductors and ferrite beads; detailed product specifications take precedence where conflicts occur.
• Designation system: A structured 12‑digit designation is prescribed. Fixed SMD inductors use the alphabetic prefix LCL, followed by digits encoding outline dimensions, shape code (e.g., D rectangular, K square), nominal inductance or impedance (letter code per IEC 61605), and tolerance code.
• Shapes and dimensions: Standardized shapes (Shape D and Shape K) with recommended outline sizes and heights drawn from R20 series values. Tables list permitted L, W, and H dimensions and applicable tolerances.
• Tolerances: Specified tolerances for outline dimensions and height, with standard and maximum values depending on size ranges.
• Nominal values and tolerances: Preferred nominal inductance/impedance values follow the E24 series (and decimal multiples/submultiples). Allowed tolerance classes are defined (letter codes) including small percentage tolerances and specific nH tolerances for inductance.
• Operating temperature ranges: Predefined lower and upper temperature selections (e.g., −55 °C to +155 °C and other ranges) with guidance on ambient temperature plus component temperature rise. New operating temperature ratings were added in this edition.
• Marking and polarity: Guidance on marking codes and directional/polarity indications; referencing IEC 61605 for marking conventions.

Applications and practical value

• Ensures consistent mechanical and identification characteristics for SMD inductors and ferrite beads used in:
  • Telecommunications equipment
  • Power supplies and DC–DC converters
  • Consumer electronics and RF modules
  • Automotive and aerospace electronics (when combined with applicable temperature/qualification specs)
• Useful for component manufacturers, PCB designers, quality/inspection engineers, test laboratories, and procurement/spec writers who need standardized dimensions, designation, and non‑electrical test guidance to enable interchangeability and reliable assembly.

Related standards

• IEC 61605:2005 - Fixed inductors: Marking codes (normative reference in IEC 62025-1)
• Other parts of the IEC 62025 series covering additional high-frequency inductive component characteristics and measuring methods

Keywords: IEC 62025-1:2007, surface mounted inductors, fixed inductors, ferrite beads, high frequency inductive components, SMD inductors, inductance codes, E24 series, operating temperature ranges.