TLLY5401 Yellow LED T-1 3/4 Through Hole - Equivalent & Substitute Parts

Part Overview

The TLLY5401 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 875 units currently in stock. The TLLY5401 operates at 2.4V forward voltage with a 2mA test current and delivers 2 millicandela brightness at 588nm dominant wavelength. Due to its obsolete status, equivalent and substitute parts from active manufacturers are necessary for new designs and long-term supply chain continuity.

Key Parameters

Parameter	TLLY5401 Value
Color	Yellow
Wavelength - Dominant	588nm
Wavelength - Peak	585nm
Voltage - Forward (Vf) Typical	2.4V
Current - Test	2mA
Millicandela Rating	2mcd
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
Viewing Angle	50°
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution of the TLLY5401 is determined by the following critical parameters:

Color and Wavelength: Yellow diffused LEDs with dominant wavelength between 585nm and 589nm
Mounting Type: Through-hole radial configuration only
Lens Type: Diffused lens with round domed top
Electrical Compatibility: Forward voltage range 2.0V to 2.4V; test current 2mA to 20mA
Package Form Factor: T-1 3/4 (5mm) or 5mm round packages
Regulatory Compliance: ROHS3 compliant; REACH unaffected

Substitute parts are grouped into two categories based on electrical operating point and brightness:

Category A - Low Current Operation (2-10mA): TLHY5401, HLMP-3401, HLMP-3401-E0002, HLMP-4719. These parts operate at similar or lower test currents with forward voltages between 1.8V and 2.4V, suitable for direct replacement in low-power indicator applications.

Category B - Higher Current Operation (20mA): 1383UYD/S530-A3, 5219673F. These parts require higher test currents (20mA) and deliver significantly higher brightness (800mcd and 12.6mcd respectively), suitable only where increased luminous intensity is acceptable and circuit design permits higher current draw.

Parameter Comparison

Parameter	TLLY5401	TLHY5401	HLMP-3401	HLMP-4719	1383UYD/S530-A3	5219673F
Manufacturer	Vishay	Vishay	Broadcom	Broadcom	Everlight	Dialight
Color	Yellow	Yellow	Yellow	Yellow	Yellow	Yellow
Wavelength - Dominant (nm)	588	588	585	585	589	588
Voltage - Forward (Vf) Typical	2.4V	2.4V	2.0V	1.8V	2.0V	2.1V
Current - Test	2mA	10mA	10mA	2mA	20mA	20mA
Millicandela Rating	2mcd	12mcd	5.7mcd	2.1mcd	800mcd	12.6mcd
Lens Transparency	Diffused	Diffused	Diffused	Diffused	Diffused	Diffused
Lens Style	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
Package / Case	Radial	Radial	Radial	Radial	Radial	Radial
Supplier Device Package	T-1 3/4	T-1 3/4	T-1 3/4	T-1 3/4	5mm Round	5mm
Height (Max)	12.80mm	12.80mm	9.19mm	9.19mm	8.90mm	8.21mm
Viewing Angle	50°	60°	60°	50°	25°	60°
Product Status	Obsolete	Active	Active	Active	Active	Active
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	Not Specified	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation - TLHY5401 (Vishay)

The TLHY5401 is the manufacturer-recommended direct equivalent from Vishay. It maintains identical forward voltage (2.4V), same wavelength characteristics (588nm dominant), and T-1 3/4 package form factor. The TLHY5401 operates at 10mA test current versus the TLLY5401's 2mA, delivering 12mcd versus 2mcd. This part is active with 3031 units in stock and carries ROHS3 compliance. Selection of TLHY5401 is appropriate where circuit design accommodates the higher test current and increased brightness is acceptable or beneficial.

Secondary Recommendation - HLMP-4719 (Broadcom)

The HLMP-4719 provides the closest electrical match to the TLLY5401, operating at identical 2mA test current and 1.8V forward voltage with 2.1mcd brightness. This part maintains T-1 3/4 package compatibility and 50° viewing angle. HLMP-4719 is active with 23019 units in stock and ROHS3 compliant. Selection is appropriate where test current must remain at 2mA and brightness preservation is critical.

Alternative Recommendation - HLMP-3401 (Broadcom)

The HLMP-3401 offers T-1 3/4 package compatibility with 10mA test current, 2.0V forward voltage, and 5.7mcd brightness. This part is active with 2300 units in stock and ROHS3 compliant. The HLMP-3401-E0002 variant in cut tape packaging provides 35845 units in stock. Selection is appropriate where moderate brightness increase and 10mA test current are acceptable.

Higher Brightness Alternatives - 1383UYD/S530-A3 (Everlight) and 5219673F (Dialight)

These parts deliver significantly higher brightness (800mcd and 12.6mcd respectively) at 20mA test current. The 1383UYD/S530-A3 operates at 2.0V forward voltage with 25° viewing angle and 5mm round package. The 5219673F operates at 2.1V forward voltage with 60° viewing angle and 4.75mm lens size. Both are active with substantial inventory. Selection is appropriate only where circuit design permits 20mA current draw and increased brightness is required.

Not Recommended - HLMP-3650 and HLMP-3651 (Broadcom)

These parts operate at 5V and 12V forward voltages respectively and are not suitable for 2.4V circuit applications. They are listed in the substitute database but represent different voltage classes.

Frequently Asked Questions (FAQ)

Q: Can TLHY5401 directly replace TLLY5401 without circuit modification?

A: The TLHY5401 shares identical forward voltage (2.4V) and wavelength characteristics. However, it operates at 10mA test current versus TLLY5401's 2mA. Direct replacement requires verification that the circuit can supply 10mA. If the original circuit limits current to 2mA via series resistance, the TLHY5401 will operate at reduced brightness. Circuit redesign may be necessary for optimal performance.

Q: What is the difference between T-1 3/4 and 5mm round packages?

A: T-1 3/4 and 5mm round are equivalent package designations for through-hole LEDs with 5mm lens diameter. Both refer to the same physical form factor. The terms are used interchangeably by different manufacturers. All substitute parts listed are mechanically compatible with TLLY5401 PCB footprints.

Q: Why does 1383UYD/S530-A3 have 800mcd brightness while TLLY5401 has only 2mcd?

A: Brightness is determined by test current and LED die efficiency. The 1383UYD/S530-A3 operates at 20mA test current versus TLLY5401's 2mA, resulting in 10x higher current and proportionally higher brightness output. This part is suitable only where the circuit design permits 20mA current draw and higher brightness is acceptable.

Q: Are all substitute parts ROHS3 compliant?

A: TLHY5401, HLMP-3401, HLMP-3401-E0002, HLMP-4719, and 5219673F are confirmed ROHS3 compliant. The 1383UYD/S530-A3 compliance status is not specified in the provided data. Verify compliance documentation with the supplier before selection for regulated applications.

Q: What viewing angle should I select?

A: The TLLY5401 has 50° viewing angle. Substitute parts range from 25° (1383UYD/S530-A3) to 60° (TLHY5401, HLMP-3401, 5219673F). Narrower viewing angles concentrate light intensity in a smaller cone; wider angles distribute light over a larger area. Select based on application requirements for indicator visibility and light distribution.

Q: Can I use HLMP-3650 or HLMP-3651 as substitutes?

A: No. HLMP-3650 operates at 5V forward voltage and HLMP-3651 at 12V. These are not compatible with 2.4V circuit applications. They represent different voltage classes and are listed in the database for reference only.

Q: What is the inventory status for each substitute?

A: TLHY5401 has 3031 units; HLMP-3401 has 2300 units; HLMP-3401-E0002 has 35845 units; HLMP-4719 has 23019 units; 1383UYD/S530-A3 has 1097 units; 5219673F has 2928 units. All substitute parts are in active production with adequate stock levels.

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