Fixed capacitors for use in electronic equipment - Part 19: Sectional specification: Fixed metallized polyethylene terephthalate film dielectric surface mount DC capacitors
2Expert Interpretation
This article provides an in-depth analysis of the IEC 60384-19:2022 standard, covering the ratings, test methods, and quality assessment requirements for surface-mount DC capacitors made of metallized PET film. It also analyzes the technological evolution and classification system and provides implementation recommendations.
Standard Overview and Background
IEC 60384-19:2022 is Part 19: Subspecification for Fixed Capacitors for Electronic Devices, specifically for **fixed metallized polyethylene terephthalate (PET) film dielectric surface mount DC capacitors**. This standard, developed by IEC TC 40, was published in July 2022, replacing the 2015 third edition. With the miniaturization and high-density assembly of electronic devices, the demand for surface mount capacitors has surged. PET film has high dielectric strength, low loss, and good self-healing properties, making it particularly suitable for DC filtering, decoupling, and other applications. This standard provides a unified framework for the quality assessment of these capacitors, ensuring interchangeability and reliability worldwide.
The standard clarifies its scope: it applies to fixed surface mount DC capacitors with metallized electrodes and PET dielectric, which can be directly mounted on printed circuit boards or hybrid circuit boards. The key attribute is **self-healing**, meaning the ability to automatically recover insulation performance after dielectric breakdown.
The standard excludes electromagnetic interference suppression capacitors (covered by IEC 60384-14).Technical Evolution and Major Changes
Compared to the 2015 version, this revision includes significant updates in structure, test methods, and quality control. Key changes include: the document structure has been reorganized according to the new sub-specification format of TC 40; new sub-clauses have been added for installation, shear testing, and solvent resistance; loss angle measurement has been added to the solder heat resistance test; batch and periodic inspection tables have been moved to Appendix A; and the inspection level for subgroup A1 has been adjusted.
The following table summarizes the key changes:| Aspects | 2015 Edition (Third Edition) | 2022 Edition (Fourth Edition) |
|---|---|---|
| Document Structure | Old structure, scattered clauses | Standardized format according to new sub-sections to avoid duplication |
| Installation Clauses | No explicit sub-clauses | Added 5.2.1, 5.2.2, 5.2.3, clarifying initial, method, and final checks |
| Shear Test | Not listed separately | Added Clause 5.5, including general and final checks |
| Soldering Heat Resistance | Capacitance Measurement Only | Added Loss Angle Measurement as Initial and Final Inspection |
| Solvent Testing | Incomplete Clauses | Improved 5.14 and 5.15, Clarifying General and Final Inspection |
| Inspection Table Location | In the Text | Moved to Appendix A for a More Concise Main Body |
These changes reflect the industry's demand for more stringent and systematic quality assurance, especially in high-risk applications such as automotive and industrial.
Ratings and Classification System
The standard specifies preferred ratings and characteristics, covering climate category, nominal capacitance, tolerance, rated voltage, etc.
Capacitors are classified into two grades: **Grade 1 (long life)** and **Grade 2 (general purpose)**. The former has more stringent requirements for electrical parameters. For example, the durability test time for Grade 1 is 2000 hours, while that for Grade 2 is 1000 hours; the loss tangent limit is also lower.
| Parameters | Grade 1 | Grade 2 |
|---|---|---|
| Withstand Voltage Test Voltage | 1.6 UR | 1.4 UR |
| Loss Tangent (C≤1μF) | ≤0.008 | ≤0.01 |
| Durability Time | 2000 h | 1000 h |
| Capacitance Change After Durability Test | ≤5% | ≤8% |
Climate categories are divided into lower limits of -55°C, -40°C, and -25°C, and upper limits of 85°C, 100°C, and 125°C. Steady-state damp heat testing lasts for 21 or 56 days. Rated voltages are taken from the R10 series (1.0, 1.6, 2.5, 4.0, 5.0, 6.3, etc.), and the sum of the DC voltage and the AC peak voltage must not exceed the rated voltage. Frequency-dependent limits for the AC component are shown in Table 1 (e.g., peak voltage ≤ 20% UR at 50 Hz).
Application Examples: In automotive engine control units, capacitors need to withstand temperatures up to 125°C. Grade 1 products should be selected and derated (category voltage of 0.5 UR at 125°C). In consumer electronics, Grade 2 is sufficient and less expensive.
Detailed Explanation of Key Test Methods
The standard specifies a series of test procedures to ensure the reliability of capacitors under various environmental and operating conditions. The following focuses on voltage testing, loss tangent measurement, and insulation resistance testing.
Voltage Testing
The test voltage is applied for 1 minute (qualification test) or 1 second (batch inspection). Grade 1 applies 1.6 times the rated voltage, and Grade 2 applies 1.4 times. No breakdown or flashover is required, but self-healing breakdown is allowed. The test circuit must meet the requirement that R1×CN is between 0.01s and 1s, and the discharge current is limited to below 1A.
Loss Tangent
Measured at 1kHz, the peak voltage should not exceed 3%UR. For capacitors with CN≤1μF, measurement at 10kHz is also required.
Limits vary with grade and capacitance value: Grade 1 ≤ 0.008 and Grade 2 ≤ 0.01 when C ≤ 1 μF; 0.01 for all grades when C > 1 μF. Accurate measurements are performed using an LCR tester.Insulation Resistance
Clean and discharge the product before measurement; apply the test voltage immediately. See Table 4 for minimum RC requirements or minimum insulation resistance. For example, when CN > 0.33 μF and rated voltage > 100 V, Grade 1 requires RC ≥ 10,000s, and Grade 2 requires ≥ 2,500s. A temperature correction factor is used for tests outside 20°C; for example, multiply by 1.59 at 30°C.
Other important tests include: **soldering heat resistance** (immersion soldering or reflow soldering, checking capacitance and loss angle changes), **substrate bending test** (bending 2mm, capacitance change ≤10%), **climatic sequence** (dry heat, damp heat, cold cycling, final capacitance change ≤3%), **steady-state damp heat** (40°C/93%RH, 21 or 56 days), and **charge-discharge test** (10,000 cycles, capacitance change Grade 1 ≤3%). The standard adopts the IECQ quality assessment system. Qualification approval can be achieved through a fixed sample size procedure or a batch/cycle-based inspection procedure. The fixed sample size procedure requires samples to be divided into Group 0 (visual, dimensional, electrical fundamental tests) and subsequent Groups 1A, 1B, 2, 3, etc. The total sample size is 144, plus 12 spares. Each group must meet zero-defect requirements. For example, Group 0 performs all electrical tests; Group 1A tests solder heat and solvent resistance; Group 3.1 includes shear, rapid temperature change, and climatic sequence tests. Batch inspection (Groups A and B) is conducted according to IL (Inspection Line), and periodic inspection (Group C) is conducted every 3 or 6 months. Key points: Subgroup A0 requires 100% testing to remove non-conforming products, and subsequent sampling inspections must monitor the number of non-conforming items per million. These procedures ensure production consistency and stability. Implementation Recommendations Recommendations for Manufacturers: Establish a testing system strictly according to standard requirements, especially the newly added shear and solvent tests. Regular calibration of equipment such as high-resistance meters and capacitance measurement bridges is recommended. For multi-voltage/capacitance series products, extreme value combinations must be covered during qualification. Pay attention to the performance of self-healing properties under different application conditions, and specify them in the detailed specifications if necessary.Recommendations for users: Select the appropriate grade and climate category based on the application environment. For example, high-reliability applications (such as medical and aerospace) should use Grade 1, and consider derating at 125°C. Request IECQ certification records at the time of purchase to confirm parameter changes after durability testing. For high-frequency applications, pay attention to the limit of the loss tangent at 10kHz.
Case Study: A communications equipment manufacturer selected a Grade 2 capacitor with a climate category of -40/100/21. After 8000 hours of accelerated aging testing, the capacitance change was still less than 5%, meeting expectations. Meanwhile, the same model of Grade 1 product showed a change of less than 2% under the same conditions, verifying the grade difference.
In summary, IEC 60384-19:2022 is the authoritative standard for metallized PET film surface mount capacitors, and its systematic testing and quality requirements provide a solid guarantee for the electronics industry. With technological advancements, higher temperature grades and more complex reliability models may be incorporated in the future.