HSDL-4271 Equivalent & Substitute Parts

Part Overview

The HSDL-4271 is an infrared (IR) emitter manufactured by Lite-On Inc., operating at 940nm wavelength with a maximum forward current of 100mA and forward voltage of 1.2V. This component is classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing system support and new design implementations. The T 1 3/4 through-hole package and 30° viewing angle define its primary application profile.

Substiute Parts

HSDL-4271

Lite-On Inc.In Stock: 2433HSDL-4271 Datasheet

Current PartRFQ

TSAL6400

Vishay Semiconductor Opto DivisionIn Stock: 89494TSAL6400 Datasheet

DirectRFQ

IR333C/H0/L10

Everlight Electronics Co LtdIn Stock: 91242IR333C/H0/L10 Datasheet

MFR RecommendedRFQ

IR333C/H2

Everlight Electronics Co LtdIn Stock: 25360IR333C/H2 Datasheet

MFR RecommendedRFQ

SIR-563ST3FN

Rohm SemiconductorIn Stock: 2941SIR-563ST3FN Datasheet

MFR RecommendedRFQ

SIR-56ST3FF

Rohm SemiconductorIn Stock: 978SIR-56ST3FF Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the HSDL-4271 is determined by the following criteria:

Primary Matching Parameters:

• Wavelength: 940nm (primary functional requirement)
• Current - DC Forward (If) Max: 100mA (electrical compatibility)
• Mounting Type: Through Hole (mechanical compatibility)
• Operating Temperature Range: -40°C minimum to 85°C maximum (thermal envelope)

Secondary Compatibility Parameters:

• Viewing Angle: 30° (optical performance)
• Package / Case: T 1 3/4 or equivalent radial 5mm diameter (physical form factor)
• Radiant Intensity: 25mW/sr @ 100mA (optical output specification)

Substitute parts are grouped based on adherence to these parameters. Parts matching all primary parameters with minor deviations in secondary parameters (forward voltage ±0.2V, radiant intensity within application tolerance, viewing angle ±10°) are classified as direct equivalents. Parts with wavelength deviation (950nm vs 940nm) or reduced radiant intensity are classified as functional alternatives with application-specific considerations.

Parameter Comparison

Engineering Selection Recommendations

Tier 1 - Direct Equivalent (Preferred):

TSAL6400 (Vishay Semiconductor Opto Division) is the primary substitute. It matches all primary parameters: 940nm wavelength, 100mA maximum forward current, through-hole mounting, and -40°C to 85°C operating range. Forward voltage deviation (1.35V vs 1.2V) is within acceptable tolerance for most applications. Radiant intensity specification is identical (25mW/sr @ 100mA). The component is active status with ROHS3 compliance and unlimited moisture sensitivity level (MSL 1), providing superior long-term availability and environmental compliance compared to the obsolete HSDL-4271.

Tier 2 - Functional Equivalent with Package Consideration:

SIR-563ST3FN (Rohm Semiconductor) maintains T 1 3/4 package compatibility and 940nm wavelength with 100mA maximum current. Forward voltage (1.34V) and viewing angle (30°) align with HSDL-4271 specifications. Radiant intensity is lower (9mW/sr @ 50mA), which may require circuit-level adjustment in applications dependent on optical output. Operating temperature minimum is -25°C (vs -40°C), reducing suitability for extended low-temperature environments. Component is active status with ROHS3 compliance.

Tier 3 - Functional Alternative with Application Verification:

IR333C/H0/L10 (Everlight Electronics Co Ltd) provides 940nm wavelength and 100mA maximum current with radial package form factor. Forward voltage matches HSDL-4271 (1.2V). Radiant intensity specification (11mW/sr @ 20mA) differs from the reference measurement point, requiring application-specific evaluation. Viewing angle (40°) exceeds HSDL-4271 specification (30°), affecting optical beam characteristics. Component is active status with ROHS3 compliance.

IR333C/H2 (Everlight Electronics Co Ltd) operates at 940nm with 100mA maximum current and 30° viewing angle. Forward voltage (1.4V) and radiant intensity (7.8mW/sr @ 100mA) represent significant deviations from HSDL-4271, suitable only for applications with relaxed optical output requirements. Component is active status.

Not Recommended:

SIR-56ST3FF (Rohm Semiconductor) operates at 950nm wavelength, deviating from the 940nm specification. Radiant intensity (5.6mW/sr @ 50mA) is substantially lower than HSDL-4271. Component is obsolete status, providing no advantage over the original part for new designs.

Frequently Asked Questions (FAQ)

Q: Can TSAL6400 be used as a direct replacement for HSDL-4271 without circuit modification?

A: TSAL6400 is electrically compatible as a direct substitute. The forward voltage difference (1.35V vs 1.2V, +0.15V) is within typical circuit tolerance for IR emitter applications. Identical radiant intensity specification (25mW/sr @ 100mA) ensures optical output compatibility. Radial package form factor (5mm diameter) is mechanically equivalent to T 1 3/4 through-hole mounting. No circuit modification is required for standard applications.

Q: What is the impact of viewing angle differences between HSDL-4271 (30°) and TSAL6400 (50°)?

A: Viewing angle defines the half-angle of the optical beam. TSAL6400's 50° viewing angle produces a wider beam pattern compared to HSDL-4271's 30° angle. In applications requiring narrow-beam optical coupling (such as focused IR transmission), this difference may affect receiver detection efficiency. Applications with diffuse optical paths or wide receiver apertures are unaffected. Optical performance must be evaluated in the specific application context.

Q: Why is SIR-56ST3FF not recommended despite T 1 3/4 package compatibility?

A: SIR-56ST3FF operates at 950nm wavelength, a 10nm deviation from the 940nm specification. This wavelength shift affects receiver spectral response matching and optical transmission characteristics in fiber-coupled or filtered applications. Radiant intensity (5.6mW/sr @ 50mA) is substantially lower than HSDL-4271 (25mW/sr @ 100mA), requiring significant circuit redesign. Additionally, SIR-56ST3FF is obsolete status, providing no supply advantage. Substitution is not recommended.

Q: Are there operating temperature limitations when substituting with SIR-563ST3FN?

A: SIR-563ST3FN specifies -25°C to 85°C operating range, compared to HSDL-4271's -40°C to 85°C. Applications requiring operation below -25°C ambient temperature cannot use SIR-563ST3FN. For standard industrial temperature ranges (-20°C to 70°C), this limitation is not a constraint. Application temperature requirements must be verified before selection.

Q: What compliance advantages do active-status substitutes provide over the obsolete HSDL-4271?

A: Active-status components (TSAL6400, SIR-563ST3FN, IR333C/H0/L10, IR333C/H2) have current manufacturing and supply chain support. ROHS3 compliance certification is available for most active alternatives, meeting environmental regulatory requirements for new product designs. Moisture sensitivity level (MSL 1 - Unlimited) for active components eliminates storage and handling constraints associated with higher MSL ratings. Long-term availability and regulatory compliance make active substitutes preferable for new designs and ongoing production support.

Q: Can IR333C/H2 be used in applications where radiant intensity is not critical?

A: IR333C/H2 is suitable for applications where optical output intensity is not a primary design constraint. The component maintains 940nm wavelength, 100mA maximum current, and 30° viewing angle matching HSDL-4271 specifications. Forward voltage (1.4V) and radiant intensity (7.8mW/sr @ 100mA) represent deviations requiring application-level evaluation. Use is limited to systems with relaxed optical performance requirements or where receiver sensitivity is sufficient to accommodate lower emitter output.