INDUSTRY COMPONENT

Photodetector (for optocoupler)

Semiconductor device that converts optical signals into electrical signals within optocouplers for electrical isolation.

Component Specifications

Definition
A photodetector in optocoupler applications is a semiconductor-based component, typically a photodiode or phototransistor, that detects incoming light from an LED emitter and converts it into proportional electrical current. It serves as the receiver element in optocoupler isolation circuits, enabling signal transmission while maintaining galvanic isolation between input and output circuits.
Working Principle
Operates on the photoelectric effect where incident photons from the optocoupler's LED emitter generate electron-hole pairs in the semiconductor material. This creates a photocurrent proportional to light intensity, which is then amplified and processed to reproduce the input signal on the isolated output side.
Materials
Silicon (Si) or Gallium Arsenide (GaAs) semiconductor materials; typically PIN photodiodes or NPN phototransistors with anti-reflective coatings; hermetic ceramic or plastic packaging with optical windows.
Technical Parameters
  • Dark Current <10 nA
  • Responsivity 0.5-0.8 A/W
  • Rise/Fall Time 2-10 μs
  • Isolation Voltage 2500-5000 Vrms
  • Spectral Response 800-950 nm (infrared)
  • Operating Temperature -40°C to +100°C
  • Current Transfer Ratio 20-600%
Standards
ISO 9001, IEC 60747-5-5, JEDEC JESD22

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Photodetector (for optocoupler).

Parent Products

This component is used in the following industrial products

Engineering Analysis

Risks & Mitigation
  • Degradation of CTR over time
  • Thermal runaway in high-current applications
  • Optical window contamination reducing sensitivity
  • ESD damage during handling
FMEA Triads
Trigger: LED output degradation over time
Failure: Decreased Current Transfer Ratio (CTR)
Mitigation: Implement burn-in testing, use conservative CTR derating (50% of initial value), and monitor with periodic functional testing.
Trigger: Moisture ingress in non-hermetic packages
Failure: Increased dark current and potential short circuits
Mitigation: Use conformal coating, hermetic packaging for harsh environments, and proper storage with desiccants.

Industrial Ecosystem

Compatible With

Interchangeable Parts

Compliance & Inspection

Tolerance
CTR variation ±20% typical, isolation voltage tested at 125% of rated value for 1 minute
Test Method
IEC 60747-5-5 for optoelectronic isolation, UL 1577 for voltage withstand, and AEC-Q101 for automotive qualification

Buyer Feedback

★★★★☆ 4.7 / 5.0 (33 reviews)

"Reliable performance in harsh Computer, Electronic and Optical Product Manufacturing environments. No issues with the Photodetector (for optocoupler) so far."

"Testing the Photodetector (for optocoupler) now; the technical reliability results are within 1% of the laboratory datasheet."

"Impressive build quality. Especially the technical reliability is very stable during long-term operation."

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Frequently Asked Questions

What is the difference between photodiode and phototransistor detectors in optocouplers?

Photodiodes offer faster response times but require external amplification, while phototransistors provide higher sensitivity and built-in gain but slower switching speeds. Selection depends on application speed and sensitivity requirements.

How does temperature affect photodetector performance in optocouplers?

Temperature variations affect dark current (doubles every 10°C rise), responsivity (decreases with temperature), and CTR (typically decreases 0.5-1.0%/°C). Proper thermal design and derating are essential for reliable operation.

Can I contact factories directly?

Yes, each factory profile provides direct contact information.

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