Panasonic LN77L Infrared Emitter - Equivalent & Substitute Parts

Part Overview

The Panasonic LN77L is an infrared (IR) emitter operating at 860nm wavelength, designed for through-hole mounting applications requiring 100mA maximum forward current and 1.6V typical forward voltage. This component is classified as obsolete, making substitute parts necessary for new designs and ongoing production support. The LN77L delivers 10mW/sr radiant intensity at 50mA with a 40° viewing angle, suitable for short-range IR transmission applications in consumer electronics and industrial control systems.

Substiute Parts

LN77L

Panasonic Electronic ComponentsIn Stock: 1134LN77L Datasheet

Current PartRFQ

HSDL-4261

Lite-On Inc.In Stock: 1202HSDL-4261 Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the Panasonic LN77L is determined by the following critical parameters:

• Wavelength compatibility: 860nm ± tolerance for IR receiver alignment
• Maximum forward current: 100mA minimum requirement
• Forward voltage: 1.6V nominal operating point
• Mounting type: Through-hole configuration for PCB integration
• Radiant intensity: Minimum output power for signal transmission
• Viewing angle: Beam divergence affecting application range
• Operating temperature range: -25°C to 85°C minimum coverage
• Package form factor: Physical dimensions for board layout compatibility

The Lite-On HSDL-4261 qualifies as a substitute based on matching maximum forward current (100mA), through-hole mounting, and similar radiant intensity output. Wavelength variation (870nm vs 860nm) and viewing angle difference (26° vs 40°) represent the primary parameter deviations requiring circuit-level evaluation.

Parameter Comparison

Engineering Selection Recommendations

The Lite-On HSDL-4261 serves as an active substitute for the obsolete Panasonic LN77L based on the following criteria:

Product Status: The HSDL-4261 maintains active manufacturing status, ensuring long-term availability and supply chain continuity compared to the LN77L's obsolete classification.

Electrical Compatibility: Both components support 100mA maximum forward current and unlimited moisture sensitivity (MSL 1), enabling direct circuit integration without component-level redesign.

Compliance & Certifications: The HSDL-4261 carries ROHS3 compliance and REACH unaffected status, meeting modern regulatory requirements for electronic component procurement.

Parameter Deviations Requiring Evaluation: The 10nm wavelength shift (870nm vs 860nm) and 0.2V forward voltage reduction (1.4V vs 1.6V) necessitate circuit-level verification. Applications with narrowband IR receivers or tight bias network tolerances must confirm spectral alignment and current-limiting resistor values. The narrower viewing angle (26° vs 40°) reduces transmission range; applications requiring wide-angle coverage may require optical redesign or alternative substitutes.

Frequently Asked Questions (FAQ)

Q: Can the HSDL-4261 directly replace the LN77L without circuit modifications?

A: Direct pin-for-pin replacement is possible if the application tolerates the 10nm wavelength difference and 0.2V forward voltage variation. However, circuit-level verification is required for applications with spectral-dependent IR receivers or precision current-limiting networks.

Q: What is the impact of the 870nm wavelength versus 860nm?

A: The 10nm difference falls within typical IR receiver spectral response windows (typically 800-900nm). Verify the receiving photodiode's peak sensitivity wavelength and spectral response curve to confirm adequate signal coupling.

Q: How does the narrower viewing angle (26° vs 40°) affect system performance?

A: The HSDL-4261's 26° beam angle concentrates radiant intensity over a smaller solid angle, reducing transmission range compared to the LN77L's 40° angle. Applications requiring wide-angle coverage should evaluate alternative substitutes or implement optical focusing elements.

Q: Are there package compatibility issues between T 1 3/4 and Radial configurations?

A: Both use through-hole mounting, but pin spacing and orientation differ. PCB layout modifications may be necessary to accommodate the radial lead configuration of the HSDL-4261.

Q: What is the significance of the forward voltage difference (1.6V vs 1.4V)?

A: The 0.2V reduction in typical forward voltage affects current-limiting resistor calculations. Recalculate series resistor values using Ohm's law (R = (Vsupply - Vf) / If) to maintain target forward current.

Q: Does the HSDL-4261 support the full operating temperature range of the LN77L?

A: No. The HSDL-4261 operates to 70°C maximum, while the LN77L extends to 85°C. Applications requiring operation above 70°C must evaluate alternative substitutes or implement thermal management.