IR91-21C Infrared Emitter 940nm Equivalent & Substitute Parts

Part Overview

The IR91-21C is an infrared (IR) emitter manufactured by Everlight Electronics Co Ltd, designed for applications requiring 940nm wavelength emission. This through-hole axial component operates at 1.2V forward voltage with a maximum DC forward current of 65mA and delivers 3mW/sr radiant intensity at 20mA. The part is Active status and ROHS3 compliant, making it suitable for modern electronic applications requiring environmental compliance.

Substitute parts are identified when equivalent functional performance can be achieved within the allowed electrical and mechanical parameters of the infrared emitter category, particularly when the primary part faces inventory constraints or application-specific requirements necessitate alternative sourcing.

Substiute Parts

IR91-21C

Everlight Electronics Co LtdIn Stock: 20124IR91-21C Datasheet

Current PartRFQ

QEB363

onsemiIn Stock: 2549QEB363 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the IR91-21C is determined by strict alignment of the following critical parameters:

Primary Substitution Criteria:

• Wavelength: 940nm (exact match required for spectral compatibility)
• Mounting Type: Through Hole (mechanical compatibility with PCB design)
• Package / Case: Axial configuration (physical form factor)
• RoHS Compliance: ROHS3 Compliant (regulatory requirement)

Secondary Compatibility Parameters:

• Voltage - Forward (Vf): Tolerance within circuit design specifications
• Current - DC Forward (If): Must not exceed circuit current-limiting capabilities
• Radiant Intensity (Ie): Application-dependent performance threshold
• Viewing Angle: Application-specific beam divergence requirement
• Operating Temperature Range: Must encompass intended application environment

The QEB363 manufactured by onsemi meets the primary substitution criteria as a 940nm infrared emitter in through-hole axial configuration with ROHS3 compliance. Electrical parameter variations exist and must be evaluated against specific circuit requirements.

Parameter Comparison

Engineering Selection Recommendations

IR91-21C Selection Criteria:

• Primary choice when maximum forward current of 65mA is required by circuit design
• Preferred when forward voltage of 1.2V aligns with existing power supply architecture
• Suitable for applications operating within -25°C to 85°C temperature range
• Active product status with 20,087 pcs inventory availability ensures supply continuity

QEB363 Selection Criteria:

• Alternative when circuit design accommodates 1.6V forward voltage
• Applicable when maximum forward current requirement is 50mA or less
• Preferred for applications requiring extended operating temperature range (-40°C to 100°C)
• ROHS3 compliant and REACH unaffected status provides additional regulatory assurance
• 2,455 pcs inventory availability supports secondary sourcing strategy

Both parts maintain ROHS3 compliance and EAR99 ECCN classification, meeting standard regulatory requirements for commercial infrared emitter applications.

Frequently Asked Questions (FAQ)

Q: Can QEB363 directly replace IR91-21C in existing circuit designs?

A: Direct replacement requires circuit design review. The QEB363 operates at 1.6V forward voltage compared to IR91-21C at 1.2V, and has a maximum forward current rating of 50mA versus 65mA. Current-limiting resistor values and power supply voltage must be re-evaluated to ensure proper operation within QEB363 specifications.

Q: What is the significance of the 0.4V forward voltage difference?

A: Forward voltage difference affects circuit power dissipation and current-limiting resistor calculations. In series resistor circuits, higher forward voltage reduces current through the resistor, potentially affecting LED brightness. Circuit simulation or testing is necessary to confirm performance equivalence in the specific application.

Q: Are the radiant intensity specifications directly comparable?

A: No. IR91-21C specifies 3mW/sr @ 20mA while QEB363 specifies 8mW/sr @ 100mA. These measurements occur at different forward currents, making direct comparison invalid. Application-specific brightness requirements must be evaluated by operating each part at its intended circuit current.

Q: Does QEB363 fit the same PCB footprint as IR91-21C?

A: Both parts use through-hole axial mounting. IR91-21C specifies "Axial, Flat Leads" while QEB363 specifies "Axial." Physical lead configuration and spacing must be verified against PCB design files to confirm mechanical compatibility.

Q: Which part is better for high-temperature applications?

A: QEB363 operates to 100°C maximum, compared to IR91-21C at 85°C maximum. For applications requiring operation above 85°C, QEB363 provides extended temperature capability. For applications within -25°C to 85°C range, both parts are suitable.

Q: Are both parts compliant with current environmental regulations?

A: Yes. Both IR91-21C and QEB363 are ROHS3 compliant. QEB363 additionally carries REACH unaffected status. Both are classified as EAR99 for export control purposes.