SIR333C Infrared Emitter - Equivalent & Substitute Parts

Part Overview

The SIR333C is an Infrared (IR) Emitter manufactured by Everlight Electronics Co Ltd, designed for applications requiring 875nm wavelength emission at forward currents up to 100mA. This active product operates across the temperature range of -40°C to 85°C and is available in radial through-hole packaging. Finding equivalent or substitute parts may be necessary due to inventory constraints, supply chain considerations, or specific application requirements that align with alternative component specifications.

Substiute Parts

SIR333C

Everlight Electronics Co LtdIn Stock: 4675SIR333C Datasheet

Current PartRFQ

QED123

onsemiIn Stock: 4736QED123 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the SIR333C is evaluated based on the following critical parameters that define functional equivalence:

• Type Classification: Both parts must be Infrared (IR) Emitters
• Wavelength Compatibility: Operating wavelength within the near-infrared spectrum (875nm–880nm range)
• Current Rating: Maximum DC forward current of 100mA
• Mounting Configuration: Through-hole radial package format
• Operating Temperature Range: Minimum coverage of -40°C to 85°C
• Product Status: Active status ensuring ongoing availability and support

The QED123 (onsemi) meets these substitution criteria as an active infrared emitter with compatible current ratings, radial through-hole packaging, and overlapping wavelength specification in the near-infrared band.

Parameter Comparison

Engineering Selection Recommendations

SIR333C Selection: Choose the SIR333C when the application requires the specified 875nm wavelength, lower radiant intensity output (7.8mW/sr), and wider 20° viewing angle. This part is suitable for applications with established design validation at these exact specifications.

QED123 Selection: The QED123 serves as a functional substitute when higher radiant intensity (50mW/sr) is acceptable or beneficial, a narrower 18° viewing angle meets application requirements, and extended operating temperature range to 100°C is needed. The QED123's RoHS3 compliance provides additional regulatory assurance for applications with environmental or compliance mandates.

Both parts share identical maximum forward current (100mA) and through-hole radial mounting, making them mechanically and electrically compatible at the circuit board level. The primary design considerations involve wavelength tolerance (875nm vs. 880nm), radiant intensity output, beam angle, and forward voltage characteristics.

Frequently Asked Questions (FAQ)

Q: Can QED123 directly replace SIR333C in existing designs? A: Direct replacement is possible at the circuit board level due to identical through-hole radial packaging and 100mA current rating. However, the application must tolerate the differences in wavelength (5nm), radiant intensity (50mW/sr vs. 7.8mW/sr), viewing angle (18° vs. 20°), and forward voltage (1.7V vs. 1.3V–2.6V). System-level validation is required if these parameters are critical to application performance.

Q: What is the significance of the wavelength difference between 875nm and 880nm? A: Both wavelengths fall within the near-infrared spectrum and are commonly used in IR sensing and transmission applications. The 5nm difference may be negligible for many applications, but systems with narrow-band optical filters or wavelength-specific detectors should verify compatibility before substitution.

Q: Does the higher radiant intensity of QED123 affect circuit design? A: The QED123's radiant intensity of 50mW/sr compared to the SIR333C's 7.8mW/sr represents significantly higher optical output. Applications may require adjustment of forward current or optical path design to prevent detector saturation or excessive signal levels. Circuit validation is recommended.

Q: Are there packaging differences between these parts? A: Both parts use radial through-hole packaging suitable for standard PCB mounting. The QED123 is specified as 5mm diameter (T 1 3/4), which is a standard radial LED form factor. Verify mechanical fit in existing PCB layouts before substitution.

Q: What compliance advantages does QED123 offer? A: The QED123 is RoHS3 compliant, meeting Restriction of Hazardous Substances requirements. If the application or supply chain mandates RoHS compliance, QED123 provides documented regulatory alignment. The SIR333C's compliance status is not specified in available data.

Q: How do the operating temperature ranges compare? A: The SIR333C operates from -40°C to 85°C, while QED123 extends to -40°C to 100°C. For applications requiring operation above 85°C, QED123 provides the necessary thermal headroom. For standard industrial applications within 85°C, both parts are suitable.