LTL42UB5N Equivalent & Substitute Parts

Part Overview

The LTL42UB5N is a blue diffused LED indicator from Lite-On Inc., designed for through-hole mounting applications requiring 3mm T-1 form factor indication. This part operates at 3.8V forward voltage with a 25mcd brightness rating and 466nm dominant wavelength. The product is currently obsolete, making equivalent substitutes necessary for ongoing maintenance, repair, and legacy system support. Substitute parts must maintain mechanical compatibility with the T-1 radial package while meeting the electrical requirements of the original circuit design.

Substiute Parts

LTL42UB5N

Lite-On Inc.In Stock: 990LTL42UB5N Datasheet

Current PartRFQ

5218132F

DialightIn Stock: 25035218132F Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LTL42UB5N is determined by the following critical parameters:

Mechanical Compatibility: Lens size (3mm T-1), mounting type (through hole radial), and maximum height (5.85mm) must be maintained to ensure physical fit in existing PCB layouts and component holders.

Optical Compatibility: Color (blue) and lens transparency (diffused) must match the original specification to preserve the intended visual indication characteristics.

Electrical Compatibility: Forward voltage (Vf) and test current must be within acceptable circuit design tolerances. The substitute part 5218132F operates at 2.7V with 2mA test current, representing a lower power requirement that is compatible with circuits designed for the original 3.8V/20mA specification when proper current-limiting resistors are employed.

Regulatory Compliance: RoHS3 compliance is required for all substitutes to meet environmental and safety standards.

The 5218132F from Dialight meets all mechanical and optical requirements while providing active product status and improved moisture sensitivity rating.

Parameter Comparison

Engineering Selection Recommendations

The 5218132F is the qualified substitute for the LTL42UB5N based on the following criteria:

Product Status: The 5218132F maintains active product status with current manufacturing support, ensuring long-term availability and supply chain stability compared to the obsolete LTL42UB5N.

Regulatory Compliance: Both parts are ROHS3 compliant and carry identical ECCN and HTSUS classifications, meeting all environmental and trade compliance requirements.

Mechanical Fit: The 5218132F maintains identical mechanical dimensions (3mm lens size, radial through-hole package, 5.86mm maximum height) with negligible tolerance variation (0.01mm height difference), ensuring direct PCB compatibility without layout modifications.

Moisture Sensitivity: The 5218132F provides superior moisture handling with MSL 1 (unlimited shelf life) compared to the original MSL 2A (4 weeks), reducing storage and handling constraints.

Electrical Consideration: The 5218132F operates at lower forward voltage (2.7V vs. 3.8V) and test current (2mA vs. 20mA). Circuit designs using current-limiting resistors will accommodate this difference. The brightness reduction (16mcd vs. 25mcd) and expanded viewing angle (100° vs. 60°) may require circuit validation in applications with strict brightness or directional viewing requirements.

Frequently Asked Questions (FAQ)

Q: Can the 5218132F directly replace the LTL42UB5N without circuit modifications?

A: Mechanical and optical compatibility is direct. Electrical compatibility depends on circuit design. If the original circuit uses a current-limiting resistor, the 5218132F will operate correctly at its specified 2.7V/2mA parameters. Circuits with fixed current sources or direct voltage application require resistor recalculation.

Q: What is the wavelength difference between these parts?

A: The LTL42UB5N has a dominant wavelength of 466nm, while the 5218132F is 470nm. Both are within the blue spectrum range. The 4nm difference is imperceptible to human vision in indication applications.

Q: Does the brightness difference affect substitution suitability?

A: The 5218132F provides 16mcd versus the original 25mcd. For general indication purposes, this reduction is acceptable. Applications requiring specific brightness levels should evaluate the 100° viewing angle of the 5218132F, which distributes light over a wider area and may compensate for lower peak intensity in certain mounting orientations.

Q: Are there any supply chain advantages to using the 5218132F?

A: Yes. The 5218132F is in active production with 2455 pieces in current inventory, compared to the obsolete LTL42UB5N with limited remaining stock (934 pieces). The active status ensures continued availability for future production runs and repairs.

Q: What is the significance of the MSL rating difference?

A: The 5218132F has MSL 1 (unlimited moisture sensitivity level), meaning it can be stored indefinitely without moisture baking requirements. The original LTL42UB5N requires moisture baking after 4 weeks of storage. This simplifies inventory management and reduces preparation time before assembly.