HLMP1719 Yellow LED T-1 Equivalent & Substitute Parts

Part Overview

The HLMP1719 is a yellow diffused T-1 through-hole LED manufactured by onsemi, designed for yellow indication applications in discrete circuit designs. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing production and maintenance applications. The HLMP1719 operates at 1.9V forward voltage with a 2mA test current, delivering 2 millicandela brightness in a 3mm round domed lens package with 50° viewing angle.

Key Parameters

Parameter	Value
Manufacturer Part Number	HLMP1719
Manufacturer	onsemi
Color	Yellow
Lens Transparency	Diffused
Lens Size	3mm, T-1
Lens Style	Round with Domed Top
Voltage - Forward (Vf) (Typ)	1.9V
Current - Test	2mA
Millicandela Rating	2mcd
Viewing Angle	50°
Wavelength - Peak	585nm
Mounting Type	Through Hole
Package / Case	Radial
Height (Max)	6.30mm
Product Status	Obsolete
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the HLMP1719 is determined by the following critical parameters:

Primary Compatibility Criteria:

Color: Yellow
Lens Transparency: Diffused
Lens Size: 3mm, T-1
Lens Style: Round with Domed Top
Mounting Type: Through Hole
Package / Case: Radial
Wavelength - Peak: 585nm (±5nm tolerance acceptable)

Secondary Electrical Criteria:

Voltage - Forward (Vf): 1.9V nominal (acceptable range: 1.8V to 2.1V for low-current applications)
Current - Test: 2mA (acceptable range: 2mA to 20mA depending on circuit design)
Millicandela Rating: 2mcd minimum (higher brightness acceptable if circuit design permits)

Tertiary Mechanical Criteria:

Height (Max): 6.30mm (acceptable range: 5.30mm to 6.55mm for standard PCB layouts)
Viewing Angle: 50° minimum (wider angles acceptable)

Substitute parts must maintain compatibility across all primary criteria and fall within acceptable ranges for secondary and tertiary criteria. Parts with significantly different forward voltages (5V, 12V) or test currents (10mA, 13mA, 20mA) require circuit redesign and are listed for reference only.

Parameter Comparison

Part Number	Manufacturer	Color	Vf (Typ)	Current - Test	mcd	Viewing Angle	Wavelength - Peak	Height (Max)	Product Status	RoHS Status
HLMP1719	onsemi	Yellow	1.9V	2mA	2mcd	50°	585nm	6.30mm	Obsolete	Not specified
3YDL-F	Bivar Inc.	Yellow	2V	2mA	2mcd	35°	590nm	5.30mm	Active	ROHS3 Compliant
HLMP-1719-A0002	Broadcom Limited	Yellow	1.8V	2mA	2.1mcd	50°	585nm	6.35mm	Active	ROHS3 Compliant
LTL-4251N	Lite-On Inc.	Yellow	2.1V	10mA	5.6mcd	60°	585nm	5.85mm	Active	ROHS3 Compliant
151031YS05900	Würth Elektronik	Yellow	2.1V	20mA	30mcd	60°	585nm	5.55mm	Active	ROHS3 Compliant
3YD-F	Bivar Inc.	Yellow	2V	20mA	20mcd	35°	590nm	5.30mm	Active	ROHS3 Compliant
HLMP-1620	Broadcom Limited	Yellow	5V	10mA	2.2mcd	60°	583nm	6.35mm	Active	ROHS3 Compliant
HLMP-1621	Broadcom Limited	Yellow	12V	13mA	2.2mcd	60°	583nm	6.35mm	Active	ROHS3 Compliant
LTL-4251	Lite-On Inc.	Yellow	2.1V	10mA	8.7mcd	40°	585nm	6.55mm	Active	ROHS3 Compliant

Engineering Selection Recommendations

Direct Substitutes (No Circuit Redesign Required):

The HLMP-1719-A0002 from Broadcom Limited is the closest direct substitute. It maintains 1.8V forward voltage and 2mA test current specifications, matching the HLMP1719 electrical profile. This part is active in production, ROHS3 compliant, and available in cut tape packaging. The 2.1mcd brightness and 50° viewing angle align with the original specification.

The 3YDL-F from Bivar Inc. operates at 2V forward voltage with 2mA test current, maintaining the low-current design intent of the HLMP1719. This part is active, ROHS3 compliant, and offers identical 2mcd brightness. The 35° viewing angle is narrower than the original 50°, suitable for applications requiring focused indication.

Compatible Substitutes (Minor Circuit Adjustment May Be Required):

The LTL-4251N from Lite-On Inc. operates at 2.1V with 10mA test current, requiring circuit current-limiting adjustment. This part maintains 585nm wavelength and offers 5.6mcd brightness with 60° viewing angle. It is active, ROHS3 compliant, and widely available.

The 151031YS05900 from Würth Elektronik operates at 2.1V with 20mA test current, requiring circuit redesign for current limiting. This part delivers 30mcd brightness with 60° viewing angle and is active, ROHS3 compliant.

Reference Only (Requires Full Circuit Redesign):

The HLMP-1620 and HLMP-1621 from Broadcom Limited operate at 5V and 12V respectively, requiring complete circuit redesign and are not suitable as direct substitutes without significant modification.

Frequently Asked Questions (FAQ)

Q: Can I use HLMP-1719-A0002 as a direct replacement for HLMP1719?

A: Yes. The HLMP-1719-A0002 maintains 1.8V forward voltage and 2mA test current, matching the electrical specifications of the HLMP1719. Both parts use identical 3mm T-1 diffused yellow lens packages with through-hole radial mounting. This is the recommended direct substitute.

Q: What is the difference between 2mA and 10mA test current specifications?

A: Test current defines the operating point at which brightness and forward voltage are measured. Parts specified at 2mA are designed for low-current applications, while 10mA parts are designed for higher-current circuits. Using a 10mA part in a 2mA circuit will result in reduced brightness. Using a 2mA part in a 10mA circuit may cause excessive brightness or reduced component life.

Q: Can I substitute a 5V LED (HLMP-1620) for the 1.9V HLMP1719?

A: No. The HLMP-1620 requires 5V forward voltage and cannot operate at 1.9V. Attempting this substitution will result in non-operation or component failure. Full circuit redesign is required to use 5V LEDs.

Q: What does "diffused" lens mean?

A: A diffused lens scatters light over a wider area, reducing peak brightness but providing more uniform illumination across the viewing angle. The HLMP1719 and its substitutes all use diffused lenses, maintaining consistent light distribution characteristics.

Q: Are all listed substitutes ROHS3 compliant?

A: All active substitute parts listed are ROHS3 compliant. The original HLMP1719 is obsolete and ROHS status is not specified. For new designs and production, use active ROHS3 compliant substitutes.

Q: What is the significance of wavelength peak at 585nm?

A: Wavelength peak defines the dominant color of the LED. All listed substitutes maintain 585nm or 590nm wavelength peaks, ensuring consistent yellow color appearance. This parameter is critical for visual indication applications where color consistency is required.

Q: Can I use LTL-4251N in place of HLMP1719 without circuit changes?

A: LTL-4251N can be used as a substitute with minor circuit adjustment. The forward voltage difference (2.1V vs 1.9V) and test current difference (10mA vs 2mA) require circuit current-limiting resistor recalculation. The part is electrically compatible but not a direct plug-in replacement.

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