LTW-42FDV6J Through Hole White LED Datasheet - 5mm Diameter - 3.0V - 90mW - English Technical Document

1. Product Overview

The LTW-42FDV6J is a high-efficiency, through-hole white LED designed for status indication and illumination in a wide range of electronic applications. It features a standard T-1 (5mm) diameter package with a diffuse lens, providing a wide viewing angle and uniform light output. This component is RoHS compliant, ensuring environmental safety and compatibility with modern manufacturing standards.

1.1 Core Advantages

• Lead-Free & RoHS Compliant: Manufactured without hazardous substances, meeting international environmental regulations.
• High Efficiency & Low Power Consumption: Delivers high luminous intensity with minimal electrical input, contributing to energy-efficient designs.
• Versatile Mounting: Suitable for both printed circuit board (PCB) and panel mounting, offering design flexibility.
• IC Compatibility: Operates at low current levels, making it directly compatible with most integrated circuit outputs without requiring complex driver stages.
• Standard Package: The popular 5mm form factor ensures easy integration and replacement in existing designs.

1.2 Target Markets

This LED is engineered for broad applicability across multiple industries, including but not limited to:

• Computer Systems: Power, hard drive, and network status indicators.
• Communication Equipment: Signal strength, link activity, and mode indicators in routers, switches, and modems.
• Consumer Electronics: Backlighting for buttons, power indicators in appliances, and decorative lighting.
• Home Appliances: Operational status lights on microwaves, washing machines, and air conditioners.
• Industrial Controls: Machine status, fault indicators, and panel illumination in control systems.

2. In-Depth Technical Parameter Analysis

This section provides a detailed breakdown of the LED's electrical, optical, and thermal characteristics, which are critical for reliable circuit design and performance prediction.

2.1 Absolute Maximum Ratings

These ratings define the limits beyond which permanent damage to the device may occur. Operation under these conditions is not guaranteed.

• Power Dissipation (Pd): 90 mW. This is the maximum amount of power the LED can dissipate as heat.
• Peak Forward Current (I_F(PEAK)): 100 mA. Permissible only under pulsed conditions (duty cycle ≤ 1/10, pulse width ≤ 10ms).
• Continuous Forward Current (I_F): 30 mA DC. The standard operating current.
• Derating Factor: 0.39 mA/°C above 30°C. The maximum allowable continuous current decreases linearly as ambient temperature increases.
• Operating Temperature Range (T_opr): -40°C to +85°C.
• Storage Temperature Range (T_stg): -40°C to +100°C.
• Lead Soldering Temperature: 260°C for a maximum of 5 seconds, measured 2.0mm from the LED body.

2.2 Electrical & Optical Characteristics

Measured at an ambient temperature (T_A) of 25°C and a forward current (I_F) of 20mA, unless otherwise specified.

• Luminous Intensity (I_V): 2500 - 8500 mcd (Typical: 4800 mcd). The light output is measured using a sensor filtered to match the human eye's photopic response (CIE curve). A ±15% testing tolerance is applied to guarantee limits.
• Viewing Angle (2θ_1/2): 60 degrees (typical). This is the full angle at which the light intensity drops to half of its peak axial value.
• Chromaticity Coordinates (x, y): Typical values are x=0.29, y=0.28, placing the white point within a specific region on the CIE 1931 chromaticity diagram. Actual bins are defined in Section 6.
• Forward Voltage (V_F): 2.8V - 3.6V (Typical: 3.0V). The voltage drop across the LED when conducting 20mA.
• Reverse Current (I_R): 10 μA maximum at a reverse voltage (V_R) of 5V. Important: This device is not designed for operation under reverse bias; this parameter is for test purposes only.

3. Binning System Specification

To ensure consistency in mass production, LEDs are sorted into bins based on key performance parameters. The LTW-42FDV6J uses a three-dimensional binning system.

3.1 Luminous Intensity Binning

LEDs are classified by their light output at I_F=20mA. The bin code is marked on the packaging.

• U1: 2500 - 4500 mcd
• V1: 4500 - 6500 mcd
• W1: 6500 - 8500 mcd

Tolerance on each bin limit is ±15%.

3.2 Forward Voltage Binning

LEDs are sorted by their forward voltage drop at I_F=20mA.

• 3E: 2.8V - 3.0V
• 4E: 3.0V - 3.2V
• 5E: 3.2V - 3.4V
• 6E: 3.4V - 3.6V

Forward voltage measurement allowance is ±0.1V.

3.3 Hue (Chromaticity) Binning

LEDs are categorized into specific regions on the CIE chromaticity diagram to control color consistency. Five hue ranks are defined (U22, U31, U32, U41, U42), each specifying a quadrilateral area of acceptable (x, y) coordinates. The typical coordinates (x=0.29, y=0.28) fall within these defined regions. The measurement allowance for color coordinates is ±0.01.

4. Performance Curve Analysis

While specific graphical curves are not detailed in the provided text, typical performance trends for such LEDs can be inferred and are crucial for design.

4.1 Forward Current vs. Forward Voltage (I-V Curve)

The relationship is exponential, typical of a diode. At the recommended 20mA operating point, the forward voltage is typically 3.0V but can vary between 2.8V and 3.6V as per the binning table. This variance necessitates the use of current-limiting resistors in series with each LED when connected in parallel to a voltage source to ensure uniform brightness.

4.2 Luminous Intensity vs. Forward Current

Light output is approximately proportional to forward current within the operating range. Operating above the absolute maximum ratings will not yield proportional increases and risks device failure.

4.3 Temperature Dependence

Luminous intensity typically decreases as the junction temperature increases. The derating factor of 0.39 mA/°C above 30°C for the forward current is implemented to manage junction temperature and maintain reliability. High-temperature operation will reduce light output and long-term lifespan.

5. Mechanical & Package Information

5.1 Outline Dimensions

The LED conforms to the standard T-1 (5mm) round through-hole package. Key dimensional notes include:

• All dimensions are in millimeters (inches provided in tolerance).
• Standard tolerance is ±0.25mm (±0.010\") unless otherwise specified.
• Maximum protrusion of resin under the flange is 1.0mm (0.04\").
• Lead spacing is measured at the point where leads emerge from the package body.

5.2 Polarity Identification

Through-hole LEDs typically have a longer anode (+) lead and a shorter cathode (-) lead. Additionally, the cathode side often has a flat spot on the plastic lens flange. Correct polarity must be observed during assembly.

6. Soldering & Assembly Guidelines

Proper handling is essential to prevent damage during manufacturing.

6.1 Storage

For long-term storage, maintain an environment not exceeding 30°C and 70% relative humidity. LEDs removed from their original moisture-barrier bags should be used within three months. For extended storage outside original packaging, use a sealed container with desiccant or a nitrogen-filled desiccator.

6.2 Lead Forming

Bend leads at a point at least 3mm away from the base of the LED lens. Do not use the lens base as a fulcrum. Lead forming must be completed before soldering and at room temperature. Apply minimal clinch force during PCB insertion to avoid mechanical stress.

6.3 Soldering Process

Critical Rule: Maintain a minimum distance of 2mm between the solder point and the base of the epoxy lens. Do not immerse the lens in solder.

• Hand Soldering (Iron): Maximum temperature 350°C for no more than 3 seconds per lead. Solder only once.
• Wave Soldering: Pre-heat to a maximum of 100°C for up to 60 seconds. Solder wave temperature should not exceed 260°C for a maximum of 5 seconds.

Warning: Excessive temperature or time will deform the lens or cause catastrophic failure. Infrared (IR) reflow soldering is not suitable for this through-hole LED product.

6.4 Cleaning

If necessary, clean only with alcohol-based solvents such as isopropyl alcohol (IPA).

7. Packaging & Ordering Information

7.1 Packaging Specification

The product is packed in anti-static bags with the bin code marked. Standard packing quantities are:

• 1000, 500, 200, or 100 pieces per packing bag.
• 10 packing bags per inner carton (total 10,000 pcs).
• 8 inner cartons per master outer carton (total 80,000 pcs).

The last pack in a shipping lot may be a non-full pack.

8. Application Design Recommendations

8.1 Drive Circuit Design

An LED is a current-driven device. To ensure uniform brightness, especially when multiple LEDs are connected in parallel, a series current-limiting resistor must be used for each LED. Connecting LEDs directly in parallel to a voltage source (without individual resistors) is not recommended, as small variances in forward voltage (V_F) will cause significant differences in current distribution and, consequently, brightness (as illustrated by Circuit B in the datasheet). The recommended circuit (Circuit A) uses a voltage source (V_CC), a series resistor (R_S), and the LED.

The resistor value can be calculated using Ohm's Law: R_S = (V_CC - V_F) / I_F, where V_F and I_F are the desired LED forward voltage and current. Use the maximum V_F from the bin table for a conservative design to ensure the current does not exceed limits even with a low-V_F LED.

8.2 Electrostatic Discharge (ESD) Protection

LEDs are sensitive to electrostatic discharge. Standard ESD precautions should be followed during handling and assembly: use grounded workstations, wrist straps, and conductive containers. Avoid touching the LED leads directly.

8.3 Thermal Management

Although power dissipation is low (90mW max), maintaining the LED within its operating temperature range is vital for longevity and stable light output. Ensure adequate airflow in the end application and adhere to the current derating guidelines for elevated ambient temperatures.

9. Technical Comparison & Differentiation

The LTW-42FDV6J positions itself as a general-purpose, high-reliability through-hole LED. Its key differentiators include a robust binning system for luminous intensity, voltage, and color, which allows designers to select parts tailored to their consistency requirements. The wide 60-degree viewing angle with a diffuse lens is ideal for applications requiring broad visibility rather than a focused beam. Its compliance with stringent soldering temperature profiles (260°C for 5s) indicates a package robust enough for standard wave soldering processes.

10. Frequently Asked Questions (FAQ)

10.1 Can I drive this LED without a series resistor?

No. Operating an LED directly from a voltage source is highly discouraged and will likely destroy the device due to uncontrolled current flow. A series resistor is mandatory for current regulation.

10.2 Why is there a ±15% tolerance on the luminous intensity bin limits?

This tolerance accounts for measurement system inaccuracies during production testing. It ensures that any LED falling within the tested bin range will meet the guaranteed minimum intensity when measured under standard conditions.

10.3 Can I use this LED for outdoor applications?

The datasheet states it is suitable for indoor and outdoor signs. However, for harsh outdoor environments, additional design considerations are necessary, such as conformal coating on the PCB to protect against moisture and UV-resistant lens materials (if the standard epoxy is not sufficient). The operating temperature range of -40°C to +85°C supports most outdoor conditions.

10.4 What does the \"U22\" or \"V1\" code on the bag mean?

This is the bin code. It tells you the performance group of the LEDs inside. For example, \"V1\" indicates luminous intensity between 4500 and 6500 mcd. You would cross-reference this with the bin tables (Section 3) to know the exact electrical and optical characteristics of that batch.

11. Practical Design Case Study

Scenario: Designing a control panel with 10 status indicators powered from a 5V rail. Uniform brightness is critical.

Design Steps:

1. Choose Operating Point: Select I_F = 20mA (standard test condition).
2. Determine Worst-Case V_F: For a conservative design, use the maximum V_F from the widest bin, 6E: V_F(max) = 3.6V.
3. Calculate Series Resistor: R_S = (V_CC - V_F(max)) / I_F = (5V - 3.6V) / 0.020A = 70 Ohms. The nearest standard value is 68 Ohms or 75 Ohms.
4. Recalculate Actual Current with 68Ω: Using typical V_F of 3.0V, I_F = (5V - 3.0V) / 68Ω ≈ 29.4mA, which is within the 30mA maximum. Using minimum V_F of 2.8V gives I_F ≈ 32.4mA, slightly over but acceptable for short periods given the peak rating. A 75Ω resistor would be safer for long-term reliability: I_F (with V_F=3.0V) ≈ 26.7mA.
5. Implement Circuit: Use one 75Ω resistor in series with each of the 10 LEDs, all connected between the 5V rail and ground.
6. Layout Consideration: Place the resistors close to the LED anodes on the PCB. Ensure the 2mm minimum solder-to-lens clearance is maintained in the footprint design.

12. Operational Principle

The LTW-42FDV6J is a semiconductor light source. It is based on an InGaN (Indium Gallium Nitride) chip that emits blue light when electrical current passes through it in the forward direction. This blue light then excites a phosphor coating inside the epoxy lens. The phosphor absorbs a portion of the blue light and re-emits it as yellow light. The combination of the remaining blue light and the emitted yellow light is perceived by the human eye as white light. The diffuse lens scatters this light, creating the wide 60-degree viewing angle.

13. Technology Trends

While through-hole LEDs like the LTW-42FDV6J remain vital for prototyping, repair, and certain industrial applications, the broader industry trend is moving towards surface-mount device (SMD) LEDs. SMD packages offer significant advantages in automated assembly, board space savings, and thermal management. However, through-hole components provide superior mechanical strength in high-vibration environments and are easier to manually solder and replace, ensuring their continued relevance in specific market segments, educational kits, and legacy system maintenance. Advances in phosphor technology and chip efficiency continue to improve the luminous efficacy and color rendering index (CRI) of white LEDs across all package types.