R4HD LED Red Diffused Through-Hole Equivalent & Substitute Parts

Part Overview

The R4HD is a red LED indication component manufactured by Bivar Inc., designed for discrete 2V radial through-hole applications. This part features a diffused red lens with a 4.00mm x 2.00mm rectangular flat-top configuration and delivers 8mcd brightness at 20mA test current. The R4HD is classified as obsolete, making identification of compatible substitute parts essential for ongoing design support and procurement continuity.

Substiute Parts

R4HD

Bivar Inc.In Stock: 1139R4HD Datasheet

Current PartRFQ

R4RD

Bivar Inc.In Stock: 840R4RD Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the R4HD is determined by strict alignment of the following electrical and mechanical parameters:

Critical Matching Parameters:

• Color: Red
• Lens Transparency: Diffused
• Lens Style: Rectangle with Flat Top
• Lens Size: 4.00mm x 2.00mm
• Mounting Type: Through Hole
• Package / Case: Radial
• Height (Max): 7.00mm
• Viewing Angle: 120°
• Current - Test: 20mA
• Moisture Sensitivity Level (MSL): 1 (Unlimited)

Allowable Variation Parameters:

• Voltage - Forward (Vf) (Typ): ±0.1V tolerance
• Millicandela Rating: Lower brightness acceptable for indication applications
• Wavelength - Peak: Red spectrum range (625nm–700nm)
• Product Status: Active status preferred for ongoing availability

The R4RD substitute part maintains identical mechanical and optical characteristics while operating at 2.1V forward voltage and delivering reduced brightness at 0.4mcd. This part is manufactured by the same supplier and carries active product status.

Parameter Comparison

Engineering Selection Recommendations

The R4RD serves as a direct mechanical and optical substitute for the obsolete R4HD. Both parts share identical physical dimensions, lens configuration, and mounting characteristics, enabling direct board-level replacement without PCB redesign.

Electrical Compatibility: The R4RD operates at 2.1V forward voltage compared to the R4HD's 2V specification, representing a 0.1V increase within standard LED tolerance ranges. Circuit designs accommodating 2V LEDs with standard current-limiting resistor configurations will function with the R4RD without modification.

Brightness Consideration: The R4RD delivers 0.4mcd brightness versus the R4HD's 8mcd rating. This represents a significant reduction in luminous intensity. Applications requiring the original 8mcd brightness level must evaluate whether reduced brightness is acceptable for the intended indication function.

Product Status Advantage: The R4RD carries active product status with 733 units in current inventory, ensuring procurement availability and long-term supply chain continuity compared to the obsolete R4HD.

Compliance: Both parts carry identical ECCN (EAR99) and HTSUS (8541.41.0000) classifications. The R4RD includes RoHS3 compliance certification, meeting current environmental regulatory requirements.

Frequently Asked Questions (FAQ)

Q: Can the R4RD replace the R4HD in existing designs without PCB modification?

A: Yes. The R4RD maintains identical mechanical dimensions (4.00mm x 2.00mm lens, 7.00mm maximum height), lens style (rectangle with flat top), and radial through-hole mounting configuration. Direct component substitution on existing PCBs is mechanically and electrically feasible.

Q: What is the impact of the 0.1V forward voltage difference between R4HD (2V) and R4RD (2.1V)?

A: The 0.1V difference falls within standard LED manufacturing tolerances and does not require circuit redesign. Existing current-limiting resistor values will function with the R4RD. Total circuit voltage drop will increase by approximately 0.1V.

Q: Why does the R4RD have significantly lower brightness (0.4mcd vs. 8mcd)?

A: The R4RD is a lower-brightness variant within the same physical package family. Applications using the R4HD for indication purposes (status signaling, visual feedback) may operate successfully with reduced brightness. Applications requiring high-intensity illumination must evaluate brightness requirements against the 0.4mcd specification.

Q: Are there packaging differences between R4HD and R4RD?

A: The R4HD is listed with standard packaging, while the R4RD is supplied in bulk packaging. Both parts use identical radial through-hole package configuration. Bulk packaging affects procurement quantity and handling but not component electrical or mechanical specifications.

Q: What compliance certifications apply to the R4RD?

A: The R4RD carries RoHS3 compliance certification, meeting current environmental and hazardous substance restrictions. Both parts share identical ECCN (EAR99) and HTSUS (8541.41.0000) trade classifications.

Q: Is the R4RD suitable for new design applications?

A: Yes. The R4RD carries active product status with current inventory availability, making it suitable for both replacement of obsolete R4HD components and new design implementations. The active status ensures long-term supply chain continuity.

Q: How do the wavelength specifications differ between these parts?

A: The R4HD operates at 625nm peak wavelength, while the R4RD operates at 700nm peak wavelength. Both wavelengths fall within the red spectrum range. The 75nm difference represents a shift toward the longer-wavelength (deeper red) end of the red spectrum but maintains red color perception in indication applications.