Semiconductor devices - Part 2: Discrete devices - Rectifier diodes

Analysis of the Standard Framework of the Fourth Edition of IEC 60747-2

The Fourth Edition of IEC 60747-2, released by the International Electrotechnical Commission (IEC) in June 2025, marks a new phase in the standardization of rectifier diode technology. This standard replaces the third edition, published in 2016, and incorporates significant technical revisions in terms of terminology, test methods, and certification requirements.

Scope of Application and Technological Evolution of the Standard

This standard applies to four categories of discrete semiconductor devices: general-purpose rectifier diodes, avalanche rectifier diodes, fast-switching rectifier diodes, and Schottky barrier diodes. Compared to the third edition, the fourth edition features the following major technical changes:

Core Terminology and Definition System

Voltage Parameter Definition

Section 3.2 of the standard specifies various voltage parameters of rectifier diodes in detail:

• Non-repetitive Peak Reverse Voltage (V-1) ...

  Current Parameter Definition

  Section 3.3 defines the current-related parameters:

  • Forward Current
    • Reverse Voltage (RRM)
      • Reverse Voltage (VR)
        • Forward Current
          • Reverse Voltage (RSM)
            • Reverse Voltage (VRRM)
              • Reverse Voltage (VR)
                • Reverse Voltage (VR)
                  • Reverse Voltage (VRSM)
                    • Reverse Voltage ( ... /strong>：Including average forward current, peak forward current, etc.
                    • Peak case non-breaking current (I_RSMC)：New important mechanical strength index
                    • Non-repetitive surge forward current (I_FSM)：Transient overload capability parameter

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                    Ratings and characteristics requirements

                    Limit value provisions

                    Section 5.2 specifies the extreme working conditions of the rectifier diode:

                    Parameter type	Test conditions	Acceptance criteria
                    Storage temperature (Tstg)	-65°C to +175°C	No performance degradation
                    Operating Junction Temperature (Tj)	Device dependent	Not exceeding maximum ratings
                    Thermal Resistance (Rth)	Standard test conditions	Meets data sheet specifications

                    Electrical Characteristics Measurements

                    Section 5.3 details the test requirements for various electrical characteristics:

                    • Positive Reverse Voltage (V_F): Measured under specified current conditions. Breakdown Voltage (V_BR): A key parameter of avalanche rectifier diodes. Reverse Current (I_R): Leakage current characteristic. Section 6.2.1 of the standard specifies the V_RSM test circuit (Figure 8) and waveform requirements. The test duration is typically a 10ms half-sine wave to ensure device reliability under transient overvoltage conditions. Section 6.2.2 details the I_FSM test method. Using the circuit shown in Figure 9, a standard surge waveform is generated through a thyristor or IGBT to verify the device's overcurrent withstand capability.

                      Avalanche Energy Test

                      For avalanche rectifier diodes, Section 6.2.3 specifies the test methods for repetitive peak reverse power (P_RRM) and surge reverse power (P_RSM), using the circuit shown in Figure 10 to ensure the reliability of the device under avalanche conditions.

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                      Thermal Characteristic Measurement Techniques

                      Section 6.4 provides accurate measurement methods for thermal resistance (R_th) and transient thermal impedance (Z_th(t)):

                      • Calibration Curve Method: The calibration curve shown in Figure 33 is used to establish the corresponding relationship between forward voltage and case temperature
                      • Electrical Junction Temperature Measurement: The forward voltage drop temperature characteristic of the diode is used to indirectly measure the junction temperature
                      • Transient Thermal Impedance Test: Evaluates the thermal response characteristics of the device under pulsed power

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                      Certification Test Requirements

                      Type Testing

                      Section 7.1 specifies the scope and requirements of type testing, including verification of all electrical and thermal characteristics to ensure that the design meets the standard requirements.

                      Routine Tests

                      Section 7.2 defines the routine test items during the production process, and Table 5 lists the minimum test requirements, including 100% forward voltage and reverse current tests.

                      Durability Test

                      Section 7.3 specifies the durability test procedure in detail:

                      Test Type	Standard Basis	Acceptance Criteria
                      High Temperature Working Life	IEC 60749-23	Characteristic Variation Range Specified in Table 6
                      Temperature Cycling	IEC 60749-25	No mechanical damage, electrical characteristics qualified
                      Power Cycling	IEC 60749-34	Thermal resistance change is within the allowable range

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                      Standard implementation recommendations

                      Manufacturer implementation guide

                      For rectifier diode manufacturers, it is recommended to focus on the following aspects:

                      • Test equipment upgrade: Update the test system in accordance with the requirements of the new standard, especially the avalanche energy test capability
                      • Document system update: Revise the data sheet and technical documentation to ensure consistency with the fourth edition of the standard terminology
                      • Quality control process: Adjust the production line test procedures to meet the new routine test requirements

                      User selection recommendations

                      For rectifier diode users, the following selection guidance is provided:

                      • Certification mark confirmation: Select products that clearly comply with IEC Products meeting the 60747-2 4th edition standard
                      • Application environment matching: Select appropriate voltage and current margins based on actual application conditions
                      • Reliability assessment: Evaluate long-term reliability by referring to the durability test requirements in the standard

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                      Technology development trends

                      Several important development trends in rectifier diode technology can be seen from the evolution of the standard:

                      • Growing demand for high-frequency applications: More detailed test requirements for fast switches and Schottky diodes
                      • Improved thermal management requirements: The newly added local thermal resistance term reflects the emphasis on thermal design
                      • Improved reliability standards: More stringent durability test requirements ensure device life
                      • Advances in testing technology: More precise measurement methods reduce test uncertainties

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                      Conclusion

                      The IEC 60747-2 4th edition international standard provides comprehensive technical specifications for the design, manufacture and application of rectifier diodes. The new standard's updates to terminology, test methods, and reliability requirements reflect the latest developments in semiconductor technology and provide the industry with a unified technical language and quality benchmark. Manufacturers and users alike should adapt to the new standard as quickly as possible to ensure product compliance and reliability.