TLDR4400 Equivalent & Substitute Parts

Part Overview

The TLDR4400 is a red diffused LED indicator manufactured by Vishay Semiconductor Opto Division, designed for through-hole mounting applications. This T-1 (3mm) LED operates at 1.8V forward voltage with a 45mcd brightness rating and 648nm dominant wavelength, suitable for standard indication circuits. The part is currently in active production status with full RoHS3 compliance and unlimited moisture sensitivity rating (MSL 1).

Substitute parts are necessary when the TLDR4400 becomes unavailable, when alternative voltage ratings are required for different circuit designs, or when different brightness levels are needed for specific application requirements.

Key Parameters

Parameter	TLDR4400 Value
Manufacturer	Vishay Semiconductor Opto Division
Color	Red
Lens Transparency	Diffused
Lens Size	3mm, T-1
Voltage - Forward (Vf) Typical	1.8V
Current - Test	20mA
Millicandela Rating	45mcd
Wavelength - Dominant	648nm
Mounting Type	Through Hole
Package / Case	Radial
Product Status	Active
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution compatibility for the TLDR4400 is determined by the following critical parameters:

Primary Compatibility Criteria:

Color: Red
Lens Transparency: Diffused
Lens Size: 3mm, T-1 form factor
Mounting Type: Through Hole
Package / Case: Radial configuration

Secondary Compatibility Criteria (Application-Dependent):

Voltage - Forward (Vf): 1.8V nominal (acceptable range: 1.7V to 2.2V with circuit redesign)
Current - Test: 20mA nominal (acceptable range: 1mA to 20mA depending on brightness requirements)
Millicandela Rating: 45mcd nominal (acceptable range: 2mcd to 45mcd depending on visibility requirements)
Wavelength - Dominant: 648nm nominal (acceptable range: 623nm to 650nm for red indication)

Substitute parts are grouped into two categories:

Category A - Direct Substitutes (Minimal Circuit Changes): Parts with matching forward voltage (1.7V to 1.8V), similar brightness (35mcd to 45mcd), and identical form factor. These require no circuit redesign.

Category B - Functional Substitutes (Circuit Redesign Required): Parts with different forward voltages (2V to 12V) or significantly different brightness levels. These require circuit modification to accommodate different voltage drops or current requirements.

Parameter Comparison

Part Number	Manufacturer	Vf (Typ)	Current - Test	mcd Rating	Wavelength - Dominant	Viewing Angle	Height (Max)	Product Status	Packaging
TLDR4400	Vishay Semiconductor Opto Division	1.8V	20mA	45mcd	648nm	80°	6.10mm	Active	Bulk
151031SS06000	Würth Elektronik	2.2V	20mA	35mcd	640nm	60°	5.55mm	Active	Bulk
4300F1LC	Visual Communications Company - VCC	1.8V	2mA	1.8mcd	—	50°	6.35mm	Not For New Designs	Bulk
HLMP-1600	Broadcom Limited	5V	10mA	2.1mcd	626nm	60°	6.35mm	Active	Bulk
HLMP-1601	Broadcom Limited	12V	13mA	2.1mcd	626nm	60°	6.35mm	Active	Bulk
HLMP-1700	Broadcom Limited	1.7V	2mA	2.1mcd	626nm	50°	6.35mm	Active	Bulk
HLMP-1700-B0002	Broadcom Limited	1.7V	2mA	2.1mcd	626nm	50°	6.35mm	Active	Cut Tape (CT)
HLMP-K101	Broadcom Limited	1.8V	20mA	45mcd	637nm	60°	6.35mm	Active	Bulk
HLMP-K150	Broadcom Limited	1.7V	1mA	2mcd	640nm	60°	6.35mm	Active	Bulk
HLMP-K150-C0002	Broadcom Limited	1.7V	1mA	2mcd	640nm	60°	6.35mm	Active	Cut Tape (CT)
LTL-1CHE	Lite-On Inc.	2V	20mA	12.6mcd	623nm	60°	5.20mm	Active	Bulk

Engineering Selection Recommendations

For Direct Substitution (No Circuit Redesign):

HLMP-K101 is the primary equivalent for TLDR4400. Both parts share identical electrical specifications: 1.8V forward voltage, 20mA test current, and 45mcd brightness rating. Both are active production parts with full RoHS3 compliance. The HLMP-K101 operates at 637nm dominant wavelength compared to TLDR4400's 648nm, representing a minor shift within the red spectrum suitable for standard indication applications. Viewing angle differs (60° vs 80°), which may affect application suitability depending on installation geometry.

For Applications Requiring Lower Brightness:

HLMP-1700 and HLMP-1700-B0002 (identical electrical specifications, different packaging) operate at 1.7V forward voltage with 2mA test current and 2.1mcd brightness. These parts are suitable for applications where reduced brightness is acceptable. Both are active production parts with full RoHS3 compliance. HLMP-1700-B0002 is available in Cut Tape packaging for automated assembly, while HLMP-1700 is supplied in Bulk.

For Applications Requiring Different Voltage Ratings:

HLMP-1600 (5V) and HLMP-1601 (12V) are available for circuits operating at higher supply voltages. Both are active production parts with full RoHS3 compliance. These parts require circuit redesign to accommodate their higher forward voltages and different current requirements.

Parts Not Recommended for New Designs:

4300F1LC (Visual Communications Company - VCC) carries "Not For New Designs" status and should not be selected for new applications despite matching 1.8V forward voltage specification.

Packaging Considerations:

All substitute parts maintain the 3mm T-1 through-hole radial form factor. Packaging format (Bulk vs. Cut Tape) affects supply and assembly processes but does not impact electrical or mechanical compatibility.

Frequently Asked Questions (FAQ)

Q: Can HLMP-K101 replace TLDR4400 without circuit modification?

A: Yes. Both parts operate at 1.8V forward voltage with 20mA test current and 45mcd brightness rating. No circuit redesign is required. The 637nm vs. 648nm wavelength difference represents a minor shift within the red spectrum and is acceptable for standard indication applications.

Q: What is the difference between HLMP-1700 and HLMP-1700-B0002?

A: Both parts have identical electrical and mechanical specifications. The difference is packaging format: HLMP-1700 is supplied in Bulk, while HLMP-1700-B0002 is supplied in Cut Tape (CT) for automated assembly processes. Selection depends on assembly method and supply chain requirements.

Q: Why does 151031SS06000 have a higher forward voltage (2.2V) than TLDR4400 (1.8V)?

A: Different LED chip designs and materials result in different forward voltage characteristics. The 151031SS06000 requires circuit redesign to accommodate the 0.4V voltage difference. This typically involves adjusting series resistor values to maintain proper current limiting.

Q: Can I use HLMP-1600 or HLMP-1601 as direct substitutes?

A: No. These parts operate at 5V and 12V forward voltages respectively, compared to TLDR4400's 1.8V. They require significant circuit redesign including different power supply connections and current-limiting resistor calculations. They are suitable only for applications specifically designed for higher voltage operation.

Q: What does "Not For New Designs" mean for part 4300F1LC?

A: This status indicates the manufacturer (Visual Communications Company - VCC) has discontinued or is phasing out this part. While it may still be available in inventory, it should not be selected for new product designs due to uncertain long-term availability and potential future supply discontinuation.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All parts listed in this reference, including TLDR4400 and all substitutes, carry RoHS3 compliance certification. All parts also have unlimited moisture sensitivity rating (MSL 1) and REACH Unaffected status.

Q: How does viewing angle affect substitution?

A: Viewing angle determines the light distribution pattern. TLDR4400 has an 80° viewing angle, while most substitutes range from 50° to 60°. A narrower viewing angle concentrates light in a smaller cone, which may affect visibility depending on installation geometry and observer position. Application requirements should determine acceptable viewing angle ranges.

Q: Can I substitute based on brightness (mcd) alone?

A: No. While brightness is important, substitution requires matching multiple parameters: forward voltage, test current, form factor, and wavelength. Brightness alone does not ensure electrical compatibility or proper circuit operation.

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