WP424SRDT Equivalent & Substitute Parts Reference

Part Overview

The WP424SRDT is a red diffused LED indicator manufactured by Kingbright, featuring a 3mm T-1 through-hole package with 20mcd brightness rating and 640nm dominant wavelength. This component is classified as obsolete, necessitating identification of active equivalent parts for ongoing design requirements and procurement continuity. Substitute parts must maintain compatibility across electrical characteristics, mechanical form factor, and optical specifications to ensure functional equivalence in circuit applications.

Substiute Parts

WP424SRDT

KingbrightIn Stock: 803WP424SRDT Datasheet

Current PartRFQ

264-7SURD/S530-A3

Everlight Electronics Co LtdIn Stock: 1078264-7SURD/S530-A3 Datasheet

SimilarRFQ

LTL-4261N

Lite-On Inc.In Stock: 785LTL-4261N Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution logic for the WP424SRDT is based on the following mandatory alignment criteria:

Critical Parameters (Must Match or Be Compatible):

• Color: Red
• Lens Transparency: Diffused
• Mounting Type: Through Hole
• Package Type: Radial (T-1 form factor)
• RoHS Compliance: ROHS3 Compliant

Important Parameters (Should Align Within Acceptable Tolerance):

• Voltage - Forward (Vf): 1.85V nominal (acceptable range: 1.8V to 2.0V for standard circuit designs)
• Current - Test: 20mA (standard test condition)
• Wavelength - Dominant: 640nm (red spectrum, acceptable range: 620nm to 660nm)
• Height (Max): 6.00mm (acceptable range: 6.00mm to 6.20mm for PCB clearance)

Moderate Parameters (May Vary Based on Application):

• Millicandela Rating: 20mcd (brightness can vary; application determines acceptable range)
• Viewing Angle: 100° (can vary; application determines acceptable range)
• Lens Size: 3mm nominal (2.90mm to 3.00mm acceptable for T-1 package)

The identified substitute parts LTL-4261N and 264-7SURD/S530-A3 satisfy the critical parameters and maintain compatibility within the important parameters range, enabling direct substitution in applications where the WP424SRDT is no longer available.

Parameter Comparison

Engineering Selection Recommendations

LTL-4261N (Lite-On Inc.) - Primary Substitute:

The LTL-4261N is the closest electrical equivalent to the WP424SRDT. Forward voltage (1.8V) aligns within 0.05V of the original specification, and dominant wavelength (638nm) remains within the red spectrum range. Both components share identical height (6.00mm) and current test rating (20mA). The LTL-4261N maintains active product status with ROHS3 compliance and unlimited moisture sensitivity rating. The primary design consideration is the reduced viewing angle (60° versus 100°), which narrows the light distribution cone. This substitution is suitable for applications where directional indication is acceptable or preferred.

264-7SURD/S530-A3 (Everlight Electronics Co Ltd) - Secondary Substitute:

The 264-7SURD/S530-A3 provides functional equivalence with notable brightness enhancement (125mcd versus 20mcd). Forward voltage (2V) represents a 0.15V increase from the original specification, requiring circuit verification to confirm acceptable operation within existing current-limiting resistor designs. Dominant wavelength (624nm) shifts toward the orange-red spectrum but remains within acceptable red LED classification. Height (6.20mm) exceeds the original by 0.20mm; PCB clearance must be verified. The narrower viewing angle (60°) matches the LTL-4261N. This substitution is appropriate for applications requiring increased brightness or where the forward voltage increase is accommodated by circuit design margins.

Compliance and Regulatory Status:

Both substitute parts maintain ROHS3 compliance, EAR99 export classification, and identical HTSUS coding (8541.41.0000) as the original WP424SRDT. Moisture sensitivity level remains at MSL 1 (Unlimited) for both alternatives, ensuring equivalent handling and storage requirements.

Frequently Asked Questions (FAQ)

Q: Can the LTL-4261N directly replace the WP424SRDT without circuit modification?

A: The LTL-4261N is electrically compatible with minimal circuit impact. Forward voltage difference (1.8V versus 1.85V) is negligible for standard current-limiting resistor designs. The primary design consideration is the reduced viewing angle (60° versus 100°), which affects light distribution but not electrical operation. No resistor recalculation is required for typical 20mA test current applications.

Q: What is the impact of using the 264-7SURD/S530-A3 with its 2V forward voltage?

A: The 0.15V increase in forward voltage (2V versus 1.85V) reduces available voltage across the current-limiting resistor by approximately 0.15V. For a standard 5V supply with 20mA target current, this represents a 3% reduction in resistor voltage drop. Existing resistor values remain functional; however, actual LED current will decrease proportionally. Recalculation is recommended if precise brightness control is critical. The increased brightness rating (125mcd) partially compensates for any current reduction.

Q: Are there mechanical compatibility issues with the substitute parts?

A: Both substitute parts maintain the through-hole radial package configuration and 3mm T-1 form factor. Height specifications (6.00mm for LTL-4261N, 6.20mm for 264-7SURD/S530-A3) are compatible with standard PCB clearances. The 264-7SURD/S530-A3 exceeds the original height by 0.20mm; verify PCB layout clearance for components or enclosures positioned above the LED. Lens diameter variations (3.00mm for LTL-4261N, 2.90mm for 264-7SURD/S530-A3) are within T-1 package tolerance and do not affect mounting hole compatibility.

Q: How do the viewing angles affect application suitability?

A: The WP424SRDT provides a 100° viewing angle, enabling visibility across a wide cone. Both substitutes reduce this to 60°, creating a narrower, more directional light distribution. Applications requiring omnidirectional indication (e.g., panel-mounted status indicators visible from multiple angles) may experience reduced visibility. Applications with fixed viewing geometry (e.g., front-panel indicators viewed from a specific direction) are unaffected. Evaluate application geometry before selection.

Q: What is the wavelength difference impact between the three parts?

A: Dominant wavelengths are 640nm (WP424SRDT), 638nm (LTL-4261N), and 624nm (264-7SURD/S530-A3). All three fall within the red LED spectrum (620nm to 660nm). The 16nm difference between the original and 264-7SURD/S530-A3 shifts perception slightly toward orange-red but remains visually red to human observers. Color matching in multi-LED indicator arrays may show slight variation; verify if color consistency is a design requirement.

Q: Are both substitute parts available in equivalent packaging quantities?

A: The WP424SRDT is supplied in bulk packaging with 728 pieces in stock. The LTL-4261N is available in bulk with 760 pieces in stock. The 264-7SURD/S530-A3 is available in bulk with 985 pieces in stock. All three parts are supplied as new original components. Packaging format (bulk) is consistent across all options.

Q: What regulatory certifications apply to the substitute parts?

A: Both LTL-4261N and 264-7SURD/S530-A3 maintain ROHS3 compliance, matching the original WP424SRDT. Export classification (EAR99) and HTSUS code (8541.41.0000) are identical. Moisture sensitivity level (MSL 1 - Unlimited) is equivalent, requiring no changes to handling or storage procedures. The LTL-4261N carries REACH Affected status, while the 264-7SURD/S530-A3 status is not specified in provided data; verify REACH compliance requirements for your specific application jurisdiction.