TLLY5400 Yellow LED T-1 3/4 Through Hole - Equivalent & Substitute Parts

Part Overview

The TLLY5400 is a yellow diffused LED in T-1 3/4 through-hole package manufactured by Vishay Semiconductor Opto Division. This part is classified as obsolete, with 1,797 units currently in stock. The TLLY5400 operates at 2.4V forward voltage with a 2mA test current and delivers 1.2mcd brightness at a 50° viewing angle. The dominant wavelength is 588nm, suitable for standard indication applications requiring low-power yellow LED operation.

Due to its obsolete status, identifying equivalent and substitute parts is essential for design continuity, long-term sourcing reliability, and production planning. Active alternatives from major manufacturers provide comparable or enhanced performance characteristics while maintaining through-hole mounting compatibility.

Key Parameters

Parameter	TLLY5400 Value
Color	Yellow
Wavelength - Dominant	588nm
Voltage - Forward (Vf) Typical	2.4V
Current - Test	2mA
Millicandela Rating	1.2mcd
Viewing Angle	50°
Lens Transparency	Diffused
Lens Style	Round with Domed Top
Mounting Type	Through Hole
Package / Case	Radial
Supplier Device Package	T-1 3/4
Height (Max)	12.80mm
RoHS Status	ROHS3 Compliant
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution eligibility for the TLLY5400 is determined by the following critical parameters:

Color & Wavelength: Yellow (588nm dominant wavelength ±3nm tolerance acceptable)
Mounting Type: Through Hole, Radial package
Package Form Factor: T-1 3/4 or 5mm equivalent
Lens Type: Diffused transparency
Voltage Compatibility: Forward voltage range 1.8V to 2.4V (circuit design dependent)
Current Rating: Test current 2mA to 20mA (design dependent)
Brightness: 1.2mcd to 12.6mcd (application dependent)
Viewing Angle: 50° to 60° (application dependent)
Compliance: RoHS3 compliant, REACH unaffected

Substitute parts must maintain through-hole radial configuration and diffused yellow lens characteristics. Variations in brightness (mcd), viewing angle, and test current are acceptable when circuit design accommodates the electrical differences. All listed substitutes are active products with confirmed inventory availability.

Parameter Comparison

Parameter	TLLY5400	TLHY5400	1383UYD/S530-A3	5219673F	HLMP-3401	HLMP-3401-E0002	HLMP-3650	HLMP-3651	HLMP-4719
Manufacturer	Vishay	Vishay	Everlight	Dialight	Broadcom	Broadcom	Broadcom	Broadcom	Broadcom
Color	Yellow	Yellow	Yellow	Yellow	Yellow	Yellow	Yellow	Yellow	Yellow
Wavelength - Dominant (nm)	588	588	589	588	585	585	585	585	585
Voltage - Forward (Vf) Typical	2.4V	2.4V	2V	2.1V	2V	2V	5V	12V	1.8V
Current - Test	2mA	10mA	20mA	20mA	10mA	10mA	10mA	13mA	2mA
Millicandela Rating	1.2mcd	10mcd	800mcd	12.6mcd	5.7mcd	5.7mcd	2.2mcd	2.2mcd	2.1mcd
Viewing Angle	50°	60°	25°	60°	60°	60°	60°	60°	50°
Lens Transparency	Diffused	Diffused	Diffused	Diffused	Diffused	Diffused	Diffused	Diffused	Diffused
Lens Style	Round Domed	Round Domed	Round Domed	Round Domed	Round Domed	Round Domed	Round Domed	Round Domed	Round Domed
Mounting Type	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole	Through Hole
Package / Case	Radial	Radial	Radial	Radial	Radial	Radial	Radial	Radial	Radial
Supplier Device Package	T-1 3/4	T-1 3/4	5mm Round	5mm	T-1 3/4	T-1 3/4 (5mm)	T-1 3/4	T-1 3/4	T-1 3/4
Height (Max)	12.80mm	12.80mm	8.90mm	8.21mm	9.19mm	9.19mm	9.19mm	9.19mm	9.19mm
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Not Specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Product Status	Obsolete	Active	Active	Active	Active	Active	Active	Active	Active

Engineering Selection Recommendations

Primary Recommendation: TLHY5400 (Vishay)

The TLHY5400 is the direct manufacturer upgrade from the obsolete TLLY5400. Both parts share identical forward voltage (2.4V), wavelength (588nm), and T-1 3/4 package geometry. The TLHY5400 operates at 10mA test current with 10mcd brightness, providing enhanced brightness while maintaining the same voltage class. This part is active with 957 units in stock and carries ROHS3 compliance. Selection of TLHY5400 eliminates design re-qualification requirements.

Secondary Recommendations by Application:

For Low-Power, Low-Brightness Applications (≤2mA operation):

HLMP-4719 (Broadcom): 1.8V forward voltage, 2mA test current, 2.1mcd brightness, 50° viewing angle. Closest electrical match to TLLY5400 with active product status and 23,019 units in stock.

For Standard Indication with 2V Operation:

HLMP-3401 (Broadcom): 2V forward voltage, 10mA test current, 5.7mcd brightness, 60° viewing angle. Available in bulk (2,300 units) or cut tape (35,845 units). HLMP-3401-E0002 in cut tape packaging offers superior inventory availability.

For Higher Brightness Applications (≥5mcd):

5219673F (Dialight): 2.1V forward voltage, 20mA test current, 12.6mcd brightness, 60° viewing angle. Suitable for applications requiring increased visibility. 2,928 units in stock.

For Voltage-Specific Applications:

HLMP-3650 (Broadcom): 5V forward voltage, 10mA test current, 2.2mcd brightness. Use when circuit operates at 5V rail.
HLMP-3651 (Broadcom): 12V forward voltage, 13mA test current, 2.2mcd brightness. Use when circuit operates at 12V rail. 16,828 units in stock.

Not Recommended for Direct Substitution:

1383UYD/S530-A3 (Everlight): 800mcd brightness significantly exceeds TLLY5400 specification. Suitable only for applications requiring substantially higher brightness. 25° viewing angle is narrower than TLLY5400. Height of 8.90mm may conflict with PCB clearance designed for 12.80mm maximum.

All recommended substitutes maintain RoHS3 compliance and through-hole radial mounting. Circuit design must accommodate differences in forward voltage and test current ratings.

Frequently Asked Questions (FAQ)

Q: Can TLHY5400 be used as a direct drop-in replacement for TLLY5400?

A: Yes. TLHY5400 shares identical forward voltage (2.4V), wavelength (588nm), and T-1 3/4 package form factor. The primary difference is increased brightness (10mcd vs. 1.2mcd) and test current (10mA vs. 2mA). Circuit design must accommodate the higher current requirement. No PCB layout changes are required.

Q: What is the difference between HLMP-3401 and HLMP-3401-E0002?

A: Both parts are electrically identical (2V forward voltage, 10mA test current, 5.7mcd brightness, 60° viewing angle). The difference is packaging: HLMP-3401 is supplied in bulk, while HLMP-3401-E0002 is supplied in cut tape (CT). HLMP-3401-E0002 offers significantly higher inventory (35,845 units vs. 2,300 units). Select based on assembly process requirements.

Q: Why is 1383UYD/S530-A3 not recommended as a direct substitute?

A: The 1383UYD/S530-A3 delivers 800mcd brightness, which is 667 times brighter than TLLY5400 (1.2mcd). This extreme brightness difference makes it unsuitable for applications designed for low-brightness indication. Additionally, its 25° viewing angle is narrower than TLLY5400's 50°, and its 8.90mm height is shorter than the TLLY5400's 12.80mm maximum, potentially causing PCB clearance conflicts.

Q: Can I use HLMP-3650 or HLMP-3651 if my circuit operates at 5V or 12V?

A: Yes, but only if your circuit is designed for those specific voltage rails. HLMP-3650 requires 5V forward voltage and HLMP-3651 requires 12V forward voltage. Do not use these parts in circuits designed for 2V to 2.4V operation. Verify circuit voltage compatibility before selection.

Q: What is the significance of the T-1 3/4 package designation?

A: T-1 3/4 refers to the through-hole LED package form factor with a 5mm lens diameter and radial lead configuration. All recommended substitutes maintain this package standard, ensuring mechanical compatibility with existing PCB footprints and component placement equipment. Package compatibility eliminates the need for PCB redesign.

Q: Are all substitute parts RoHS3 compliant?

A: All recommended substitutes carry RoHS3 compliance certification. The 1383UYD/S530-A3 does not specify RoHS status in the provided data. Verify RoHS compliance with the manufacturer if regulatory compliance is required for your application.

Q: What is the difference between diffused and clear lens transparency?

A: Diffused lenses scatter light over a wider viewing angle, reducing peak brightness but improving visibility from off-axis positions. All TLLY5400 substitutes listed maintain diffused lens transparency, matching the original part's optical characteristics. Clear lens alternatives are not included in this substitution guide.

Q: How do I determine which substitute is best for my application?

A: Identify your circuit's voltage rail (2V, 5V, 12V, etc.), required brightness level (mcd), and viewing angle requirement. Match these parameters to the substitute part table. If your circuit operates at 2V to 2.4V with low-brightness requirements, TLHY5400 or HLMP-4719 are optimal. For higher brightness, select 5219673F or HLMP-3401. For different voltage rails, select HLMP-3650 (5V) or HLMP-3651 (12V).

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