Overview - IEC 60747-5-5:2020 (Photocouplers / Optocouplers)
IEC 60747-5-5:2020 is the international standard that defines terminology, essential ratings, safety tests and measuring methods for photocouplers (also called optocouplers). It applies to optoelectronic isolation devices such as phototransistor and phototriac output couplers and covers both functional characteristics and electrical safety aspects, including requirements for devices that provide protection against electric shock.
This 2020 edition updates the previous release and includes notable changes such as an optional data sheet basic insulation rating per IEC 60664-1:2007, editorial corrections on the use of VIORM, fixes to timing figures, and an alternative surge pulse VIOSM test method.
Key technical topics and requirements
- Terminology and symbols used for limiting values and ratings.
- Electrical characteristics for common types:
- Phototransistor output photocouplers
- Phototriac output photocouplers / solid-state opto-relays
- Safety and insulation: datasheet ratings, safety ratings, rated isolation voltages, and electrical safety test sequences for photocouplers that provide protection against electric shock.
- Measuring methods (specified procedures and test circuits) for parameters including:
- Current transfer ratio (CTR)
- Input-to-output capacitance
- Isolation resistance and isolation withstand testing
- Partial discharge performance
- Collector-emitter saturation voltage (VCE(sat)) and switching times (ton, toff)
- Peak off-state and on-state voltages/currents, DC off/on-state currents
- Holding current, critical dV/dt, trigger input current
- Common Mode Transient Immunity (CMTI)
- Test types and sequences: routine, sample and type tests, plus annexed input/output safety test circuits and precautions.
Practical applications
- Ensures safe, repeatable characterization and documentation of galvanic isolation components used to separate low-voltage control electronics from high-voltage power circuits.
- Used for designing and qualifying optocouplers in:
- Power supplies, motor drives and inverters
- Telecom and industrial control systems
- Medical and consumer electronics (where isolation and safety ratings are critical)
- Solid-state relays and signal-isolating interfaces
- Supports manufacturers in producing compliant datasheets (insulation ratings, VIORM/VIOSM references) and guides test laboratories performing conformity assessments.
Who should use this standard
- Semiconductor and optoelectronic component manufacturers
- Product design engineers (power and control systems)
- Test laboratories and certification bodies performing safety and performance validation
- Procurement and compliance teams specifying isolation components
Related standards
- IEC 60664-1 (insulation coordination and basic insulation ratings)
- Other parts of the IEC 60747 series for semiconductor device families
For device selection, testing and compliance, IEC 60747-5-5 is the authoritative reference for safe and consistent specification of photocoupler performance and insulation properties.
