LTL42FTBR3DH183Y Blue LED Lamp Datasheet - Through Hole - 470nm - 20mA - 78mW - English Technical Document

1. Product Overview

This document details the specifications for a blue, through-hole mounted LED lamp. The device is designed as a Circuit Board Indicator (CBI), utilizing a black plastic right-angle holder (housing) that mates with the LED component. This design enhances contrast ratio and facilitates easy assembly on printed circuit boards (PCBs). The product is available in configurations suitable for creating stackable horizontal or vertical arrays.

1.1 Key Features

• Designed for ease of circuit board assembly.
• Black housing improves contrast ratio for better visibility.
• Features low power consumption and high efficiency.
• Compliant with RoHS directives and is a lead-free product.
• Utilizes InGaN blue chips with a source color of 470nm in a T-1 lamp package.

1.2 Target Applications

• Communication equipment
• Computer peripherals and systems
• Consumer electronics
• Industrial equipment and controls

2. Technical Parameters: In-Depth Objective Interpretation

2.1 Absolute Maximum Ratings

The following ratings define the limits beyond which permanent damage to the device may occur. All values are specified at an ambient temperature (TA) of 25°C.

• Power Dissipation (Pd): 78 mW maximum. This is the total power the device can safely dissipate as heat.
• Peak Forward Current (IFP): 60 mA maximum. This current is permissible only under pulsed conditions with a duty cycle ≤ 1/10 and a pulse width ≤ 10μs.
• DC Forward Current (IF): 20 mA maximum. This is the recommended continuous operating current.
• Operating Temperature Range (Topr): -30°C to +85°C. The device is guaranteed to function within this ambient temperature range.
• Storage Temperature Range (Tstg): -40°C to +100°C.
• Lead Soldering Temperature: 260°C for a maximum of 5 seconds, measured 2.0mm (0.079\") from the LED body.

2.2 Electrical and Optical Characteristics

These parameters define the typical performance of the device under normal operating conditions at TA=25°C.

• Luminous Intensity (Iv): 1150 mcd (Min), 1900 mcd (Typ) when driven at IF=20mA. This is the measure of perceived power of visible light emitted.
• Viewing Angle (2θ1/2): 30 degrees (Typ). This is the full angle at which the luminous intensity is half the value at the center (0°).
• Peak Emission Wavelength (λP): 468 nm (Typ). The wavelength at which the spectral radiant intensity is maximum.
• Dominant Wavelength (λd): 470 nm (Typ) at IF=20mA. This is the single wavelength that perceptually matches the color of the emitted light.
• Spectral Line Half-Width (Δλ): 25 nm (Typ). A measure of the spectral purity or bandwidth of the emitted light.
• Forward Voltage (VF): 2.6V (Min), 3.2V (Typ), 3.8V (Max) at IF=20mA. The voltage drop across the LED when operating.
• Reverse Current (IR): 10 μA maximum at a Reverse Voltage (VR) of 5V. Important: The device is not designed for reverse operation; this test condition is for characterization only.

3. Binning System Specification

To ensure consistency in applications, LEDs are sorted (binned) based on key optical parameters. The luminous intensity bin code is marked on each packing bag.

3.1 Luminous Intensity Binning

Binning is performed at a test current of 20mA. The tolerance for each bin limit is ±15%.

• Bin Q: 1150 mcd (Min) to 1500 mcd (Max)
• Bin R: 1500 mcd (Min) to 1900 mcd (Max)
• Bin S: 1900 mcd (Min) to 2500 mcd (Max)
• Bin T: 2500 mcd (Min) to 3200 mcd (Max)
• Bin U: 3200 mcd (Min) to 4200 mcd (Max)

3.2 Dominant Wavelength Binning

Binning is performed at a test current of 20mA. The tolerance for each bin limit is ±1nm.

• Bin B07: 460.0 nm (Min) to 465.0 nm (Max)
• Bin B08: 465.0 nm (Min) to 470.0 nm (Max)
• Bin B09: 470.0 nm (Min) to 475.0 nm (Max)

4. Performance Curve Analysis

Typical performance curves illustrate the relationship between key parameters under varying conditions. These are essential for robust circuit design.

• Relative Luminous Intensity vs. Forward Current: Shows how light output increases with current, typically in a sub-linear manner, highlighting the importance of current regulation.
• Relative Luminous Intensity vs. Ambient Temperature: Demonstrates the negative temperature coefficient of light output; intensity decreases as ambient temperature rises.
• Forward Voltage vs. Forward Current: Depicts the exponential I-V characteristic of the diode, crucial for calculating series resistor values.
• Spectral Distribution: A graph showing the relative radiant power across wavelengths, centered around the peak wavelength of ~468nm with a characteristic half-width.

5. Mechanical and Packaging Information

5.1 Outline Dimensions

The device uses a standard T-1 (3mm) LED lamp housed in a black plastic right-angle holder. Key dimensional notes include:

• All dimensions are provided in millimeters, with tolerances of ±0.25mm unless otherwise specified.
• The housing material is black plastic.
• The LED itself features a blue diffused lens.

5.2 Polarity Identification

The cathode lead is typically identified by a flat spot on the LED lens, a shorter lead (if trimmed uniformly by the user), or a marking on the housing. Always refer to the detailed outline drawing for definitive polarity identification.

5.3 Packing Specification

The LEDs are supplied in bulk packaging. The packing specification details the quantity per inner box (revised to 4,200 pieces/inner) and the overall master carton configuration, including dimensions and gross weight for logistics planning.

6. Soldering and Assembly Guidelines

6.1 Storage Conditions

For optimal shelf life, store LEDs in an environment not exceeding 30°C and 70% relative humidity. If removed from the original moisture-barrier bag, use within three months. For extended storage outside the original packaging, use a sealed container with desiccant or a nitrogen ambient.

6.2 Lead Forming

If leads need to be bent, perform this operation before soldering and at normal room temperature. Bend the leads at a point at least 3mm from the base of the LED lens. Do not use the base of the lead frame as a fulcrum. Apply minimum clinch force during PCB insertion to avoid mechanical stress.

6.3 Soldering Process

Critical: Maintain a minimum clearance of 2mm from the base of the lens/holder to the solder point. Do not immerse the lens/holder in solder.

• Hand Soldering (Iron): Maximum temperature 350°C for a maximum of 3 seconds (one time only).
• Wave Soldering: Pre-heat to a maximum of 100°C for up to 60 seconds. Solder wave temperature should be a maximum of 260°C for a maximum of 5 seconds. Ensure the device is positioned so the solder wave does not come within 2mm of the lens/holder base.
• Important Note: IR reflow soldering is not suitable for this through-hole type LED product. Excessive temperature or time can cause lens deformation or catastrophic failure.

6.4 Cleaning

If cleaning is necessary, use alcohol-based solvents such as isopropyl alcohol. Avoid harsh or abrasive cleaners.

7. Application Suggestions and Design Considerations

7.1 Drive Method

LEDs are current-operated devices. To ensure uniform brightness when using multiple LEDs, it is strongly recommended to drive each LED with its own current-limiting resistor connected in series (Circuit Model A). Connecting LEDs directly in parallel (Circuit Model B) is not recommended due to variations in forward voltage (VF) characteristics, which will cause uneven current sharing and thus uneven brightness.

7.2 Electrostatic Discharge (ESD) Protection

This LED is susceptible to damage from electrostatic discharge. Implement the following ESD control measures in the handling and assembly area:

• Personnel must wear grounded wrist straps or anti-static gloves.
• All equipment, workstations, and storage racks must be properly grounded.
• Use ionizers to neutralize static charge that may accumulate on the plastic lens during handling.
• Ensure personnel are trained in ESD prevention procedures.

7.3 Thermal Management

While the power dissipation is relatively low (78mW max), operating at the upper limit of the temperature range (+85°C) will significantly reduce light output, as shown in the temperature characteristic curve. For consistent long-term performance, design for adequate ventilation and avoid placing the LED near other heat-generating components.

8. Technical Comparison and Differentiation

This through-hole LED lamp differentiates itself through its integrated right-angle black holder, which simplifies assembly and improves optical contrast compared to standard radial LEDs mounted in separate clips or standoffs. The specified binning for both intensity and wavelength provides designers with predictable performance for applications requiring color or brightness matching across multiple indicators. Its compatibility with standard wave and hand soldering processes makes it suitable for a wide range of mainstream electronics manufacturing workflows.

9. Frequently Asked Questions (Based on Technical Parameters)

9.1 What is the difference between Peak Wavelength and Dominant Wavelength?

Peak Wavelength (λP) is the physical wavelength at which the emitted optical power is greatest. Dominant Wavelength (λd) is a colorimetric quantity derived from the CIE chromaticity diagram; it is the single wavelength that the human eye perceives as matching the color of the source. For monochromatic sources like this blue LED, they are typically very close (468nm vs. 470nm).

9.2 Can I drive this LED at 30mA for higher brightness?

No. The Absolute Maximum Rating for DC Forward Current is 20mA. Exceeding this rating risks reducing the device's lifetime or causing immediate failure due to overheating or current overstress.

9.3 How do I calculate the series resistor value?

Use Ohm's Law: R = (Vsupply - VF) / IF. For example, with a 5V supply (Vsupply), a typical VF of 3.2V, and the desired IF of 20mA (0.02A): R = (5 - 3.2) / 0.02 = 90 Ohms. Always use the maximum VF from the datasheet (3.8V) for a conservative design to ensure the current does not exceed limits: R_min = (5 - 3.8) / 0.02 = 60 Ohms. Select a standard resistor value between 60 and 90 Ohms, considering power rating (P = IF² * R).

9.4 Is this LED suitable for outdoor use?

The datasheet states the LED is good for indoor and outdoor signs. However, the operating temperature range is -30°C to +85°C. For harsh outdoor environments with direct sunlight, UV exposure, or wider temperature swings, the specific installation (enclosure, sealing) must be evaluated to ensure the local ambient temperature around the LED remains within specification and that the materials are weather-resistant.

10. Practical Design and Usage Case

Scenario: Designing a status indicator panel for industrial equipment. Multiple blue indicators are needed to show \"system active,\" \"communication link established,\" and \"fault condition.\" Using the LTL42FTBR3DH183Y LED:

1. Binning Selection: Specify Bin R for luminous intensity (1500-1900mcd) and Bin B08 for dominant wavelength (465-470nm) to ensure all indicators on the panel have consistent brightness and color.
2. Circuit Design: Design a drive circuit for a 24V DC supply. Using the max VF of 3.8V and IF=20mA, the series resistor is R = (24V - 3.8V) / 0.02A = 1010 Ohms. A 1kΩ, 1/4W resistor is suitable. Each LED has its own resistor.
3. PCB Layout: Place the LED mounting holes according to the mechanical drawing. Ensure a keep-out area of at least 2mm around the LED base for soldering clearance.
4. Assembly Process: During assembly, operators follow ESD protocols. LEDs are inserted, the leads are wave-soldered using the specified profile, ensuring the solder does not wick too high. No post-solder cleaning is required.

11. Operating Principle Introduction

This device is a Light Emitting Diode (LED). It operates on the principle of electroluminescence in a semiconductor material (InGaN - Indium Gallium Nitride for blue light). When a forward voltage is applied across the p-n junction, electrons and holes recombine, releasing energy in the form of photons (light). The specific bandgap energy of the InGaN material determines the wavelength (color) of the emitted light, which in this case is in the blue region (~470nm). The diffused lens and black housing shape and direct the emitted light.

12. Technology Trends (Objective Perspective)

The through-hole LED technology represented by this product is a mature and widely adopted solution for indicator applications. Current industry trends show a gradual shift towards surface-mount device (SMD) LEDs for most new designs due to their smaller footprint, suitability for automated pick-and-place assembly, and often lower profile. However, through-hole LEDs remain relevant in applications requiring higher mechanical robustness, easier manual assembly/rework, or where the specific optical characteristics of a lensed package in a holder are advantageous. Advances continue in the efficiency (lumens per watt) and color consistency of the semiconductor chips used across all LED package types.