GB/T 40853.2-2023 High frequency inductive components - Electrical characteristics and measuring methods - Part 2: Rated current of inductors for DC to DC converters
1 Scope
This document specifies the measuring methods of the rated direct current limits for small inductors.
Standardized measuring methods for the determination of ratings enable users to accurately compare the current ratings given in various manufacturers’ data books.
This document is applicable to leaded and surface mount inductors with dimensions according to IEC 62025-1 and generally with rated current less than 22 A, although inductors with rated current greater than 22 A are available that fall within the dimension restrictions of this document (no larger than a 12 mm × 12 mm footprint approximately). These inductors are typically used in DC-to-DC converters built on PCBs, for electric and telecommunication equipment, and small size switching power supply units.
The measuring methods are defined by the saturation and temperature rise limitations induced solely by direct current.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T2421-2020 Environmental testing - General and guidance
IEC 62025-1 High frequency inductive components - Non-electrical characteristics and measuring methods - Part 1: Fixed, surface mounted inductors for use in electronic and telecommunication equipment
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
DC saturation limited current
allowable value of DC current for which the decrease of the inductance is within the specified value
3.2
temperature rise limited current
allowable value of DC current for which the self-generation heat of the inductor results in
temperature rise within the specified value
4 Standard atmospheric conditions
4.1 Standard atmospheric conditions for testing
Standard atmospheric conditions for testing shall be as follows (see GB/T 2421-2020, 4.3):
——temperature: 15 °C to 35 °C;
——relative humidity: 25% to 75%;
——air pressure: 86 kPa to 106 kPa.
In the event of dispute or where required, the measurements shall be repeated using the referee temperatures and such other conditions as given in 4.2.
4.2 Reference conditions
For reference purposes, one of the standard atmospheric conditions for referee tests taken from GB/T 2421-2020, 4.2, shall be selected and shall be as follows:
——temperature: 20 °C ± 2 °C;
——relative humidity: 60% to 70%;
——air pressure: 86 kPa to 106 kPa.
