IEC 60384-21:2024

Overview

IEC 60384-21:2024 is the latest sectional specification for fixed surface mount multilayer capacitors of ceramic dielectric, Class 1. It applies to unencapsulated SMD multilayer ceramic capacitors (MLCCs) with defined temperature coefficients (Class 1) intended for mounting on printed circuit boards or directly onto hybrid substrates. The standard specifies preferred ratings and characteristics, required tests and measurement methods, and the quality assessment procedures selected from IEC 60384-1:2021. Note: capacitors intended specifically for electromagnetic interference suppression are excluded (see IEC 60384-14).

Key topics and requirements

• Preferred ratings and characteristics: nominal capacitance, rated and category voltages, rated temperature, temperature coefficient coding (including additions such as C0G, U2J), and dimension coding.
• Electrical measurements: capacitance, tangent of loss angle (tan δ), insulation resistance and voltage proof tests - with limits and preferred values defined in tables.
• Mechanical and soldering tests: shear test, substrate bending test, resistance to soldering heat (with reflow profiles), solderability, and robustness of terminations for strip terminations.
• Environmental and reliability tests: rapid change of temperature, climatic sequence, damp heat (steady state and accelerated), and endurance tests with recovery and final inspection procedures.
• Visual and dimensional inspection: specified visual examination criteria (cracks, delamination, exposed electrodes) and dimensional tolerances.
• Quality assessment and inspection: Annex C (now normative) provides quality conformance inspection procedures, lot formation, test schedules and assessment levels. Clause C.5 introduces a new test schedule for quality conformance inspection.
• Editorial and structural changes: the 2024 edition was restructured to comply with ISO/IEC Directives, part 2; terms replaced by letter symbols; Annex B changed to normative; and cross-references provided in Annex X.

Practical applications and users

This standard is essential for:

• Capacitor manufacturers designing and qualifying Class 1 SMD MLCCs (tight temperature coefficients for timing and precision circuits).
• Component qualification engineers and test labs performing acceptance, reliability and conformance testing.
• PCB and hybrid circuit designers specifying capacitors for high-stability analog, timing, RF and precision applications.
• Procurement and quality assurance teams requiring standardized ratings, marking and inspection criteria.
• Regulatory and standards professionals aligning product detail specifications with IEC 60384-1:2021 practices.

Related standards

• IEC 60384-1:2021 - generic requirements, quality assessment procedures.
• IEC 60384-14 - capacitors for electromagnetic interference suppression (EMI).
• ISO/IEC Directives, Part 2 - editorial structure and document formatting guidance.

Keywords: IEC 60384-21:2024, fixed surface mount multilayer capacitors, Class 1 MLCC, ceramic dielectric, SMD capacitors, quality conformance inspection, solderability, reflow profile, tan δ, temperature coefficient.