LTW-404M01H279 Through Hole LED Lamp Datasheet - Multi-Color Array - 30mA Max - English Technical Document

1. Product Overview

The LTW-404M01H279 is a multi-color, through-hole LED lamp designed as a Circuit Board Indicator (CBI). It consists of a black plastic right-angle housing that integrates multiple LED chips. The primary function is to provide clear, solid-state visual indication on electronic circuit boards. Its design emphasizes ease of assembly and integration into various electronic systems.

1.1 Core Advantages

• Ease of Assembly: The right-angle holder is designed for straightforward circuit board mounting and is stackable for creating arrays.
• Enhanced Contrast: The black housing material improves the contrast ratio of the emitted light, making the indicator more visible.
• Robust Construction: Utilizes solid-state light sources (InGaN chips for Blue/White/Green) for reliability and long life.
• Environmental Compliance: The product is lead-free and compliant with RoHS directives.
• Integrated Protection: Features built-in Zener diodes for ESD (Electrostatic Discharge) protection, enhancing durability during handling and operation.

1.2 Target Applications

This LED lamp is suitable for a broad range of electronic equipment requiring status indication. Key application areas include:

• Communication Equipment: Status lights on routers, switches, and modems.
• Computer Systems: Power, HDD activity, and diagnostic indicators on motherboards and peripherals.
• Consumer Electronics: Indicator lights on audio/video equipment, home appliances, and gaming devices.
• Industrial Controls: Machine status, fault, and operational mode indicators on control panels and automation systems.

2. In-Depth Technical Parameter Analysis

2.1 Absolute Maximum Ratings

These 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): Varies by color: White (102 mW), Blue (74 mW), Green (64 mW). This is the maximum allowable power the LED can dissipate as heat.
• Peak Forward Current (IFP): For pulsed operation only (duty cycle ≤ 1/10, pulse width ≤ 10ms). White/Blue: 100 mA, Green: 60 mA.
• DC Forward Current (IF): The maximum continuous forward current. White: 30 mA, Blue/Green: 20 mA.
• Temperature Ranges: Operating: -30°C to +85°C. Storage: -40°C to +100°C.
• Lead Soldering Temperature: 260°C maximum for 5 seconds, measured 2.0mm (0.079\") from the LED body.

2.2 Electrical & Optical Characteristics

These are the typical performance parameters measured at TA=25°C and IF=8mA, unless otherwise stated.

• Luminous Intensity (Iv): The light output measured in millicandelas (mcd). Typical values: White: 200 mcd, Green: 180 mcd, Blue: 30 mcd. The specification includes a ±15% testing tolerance.
• Viewing Angle (2θ1/2): The full angle at which intensity drops to half its peak value. White: 100°, Green/Blue: 120°. This indicates a relatively wide viewing cone.
• Forward Voltage (VF): The voltage drop across the LED at the test current. Typical: 2.8V for all colors, with a range from 2.4V to 3.3V depending on the specific chip and bin.
• Dominant Wavelength (λd): Defines the perceived color. Blue: 465 nm (range 460-470 nm). Green: 525 nm (range 520-530 nm).
• Chromaticity Coordinates (x, y): For the white LEDs, these coordinates define the color point on the CIE 1931 diagram. The typical value is given as (0.24, 0.20). Specific bins (D1-D4) have defined coordinate ranges detailed in the bin table.
• Reverse Current (IR): Maximum 10 μA at a reverse voltage (VR) of 5V. Important: The device is not designed for operation in reverse bias; this test condition is for characterization only.

3. Binning System Explanation

The product uses a binning system to categorize LEDs based on key optical and electrical parameters, ensuring consistency within a batch. The LTW-404M01H279 uses a three-code system.

3.1 Wavelength / Chromaticity Binning

• Blue (Code 1): Binned by Dominant Wavelength. B07: 460-465 nm, B08: 465-470 nm.
• White (Code 2): Binned by Chromaticity Coordinates (CCx,y) into four quadrants: D1, D2, D3, D4. Each quadrant has specific (x,y) coordinate boundaries as shown in the CIE diagram and table.
• Green (Code 3): Binned by Dominant Wavelength. G09: 520-525 nm, G10: 525-530 nm.

3.2 Luminous Intensity Binning

Intensity is grouped within broad ranges for each color, combined with the hue/color coordinate bin.

• White: 120-680 mcd (across all D1-D4 bins).
• Green: 110-310 mcd (across G09/G10 bins).
• Blue: 18-50 mcd (across B07/B08 bins).

3.3 Forward Voltage Binning

Forward voltage is specified as a range for each color group rather than discrete bins: White: 2.4-3.2V, Blue/Green: 2.5-3.3V.

Note: A tolerance of ±15% applies to the limits of each bin, and a measurement allowance of ±0.01 is applied to color coordinates.

4. Performance Curve Analysis

The datasheet provides typical characteristic curves for each LED color (Blue, Green, White). While the specific graphs are not detailed in the text, they typically illustrate the following relationships, crucial for circuit design:

• Current vs. Voltage (I-V Curve): Shows the exponential relationship, helping to determine the required driving voltage for a given current.
• Luminous Intensity vs. Forward Current (Iv-IF Curve): Demonstrates how light output increases with current, up to the maximum rated limits.
• Luminous Intensity vs. Ambient Temperature (Iv-TA Curve): Illustrates the decrease in light output as the junction temperature rises, which is critical for thermal management in the application.
• Forward Voltage vs. Ambient Temperature (VF-TA Curve): Shows the temperature dependence of the forward voltage, which can be used for temperature sensing in some designs.

Designers should consult these curves to optimize drive current for desired brightness and to understand thermal derating effects.

5. Mechanical & Packaging Information

5.1 Outline Dimensions

The device uses a through-hole, right-angle mounting configuration. Key mechanical notes from the datasheet:

• All dimensions are provided in millimeters, with inches in parentheses.
• Standard tolerance is ±0.25mm (±0.010\") unless otherwise specified.
• The housing is made of black plastic.
• The array consists of 10 LEDs: LEDs 1-6 are green with green diffused lenses; LEDs 7-9 are white with white diffused lenses; LED 10 is blue with a blue diffused lens.
• A critical mechanical specification is the protruded LED height, which is 0.20 ± 0.14 mm from the housing.

5.2 Polarity Identification

For through-hole LEDs, polarity is typically indicated by lead length (the longer lead is the anode) or by a flat spot on the lens or housing. The specific marking for this model should be verified on the dimensional drawing.

5.3 Packing Specification

The product is supplied in packaging suitable for automated assembly and to prevent damage during shipping and handling. The exact reel or tube packaging dimensions and quantities are defined in the packing specification section of the datasheet.

6. Soldering & Assembly Guidelines

6.1 Storage Conditions

LEDs should be stored in an environment not exceeding 30°C and 70% relative humidity. If removed from the original moisture-barrier bag, they should be used within three months. For longer storage outside the original packaging, use a sealed container with desiccant or a nitrogen-filled desiccator.

6.2 Cleaning

If cleaning is necessary, use alcohol-based solvents like isopropyl alcohol. Avoid harsh or abrasive chemicals.

6.3 Lead Forming

If leads need to be bent, this must be done before soldering and at room temperature. The bend should be made at least 3mm away from the base of the LED lens. Do not use the LED body as a fulcrum. Apply minimal force during PCB insertion to avoid stress.

6.4 Soldering Process

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

• Hand Soldering (Iron): Maximum temperature: 350°C. Maximum time: 3 seconds per joint. One soldering cycle only.
• Wave Soldering: Pre-heat: Max 120°C for up to 100 seconds. Solder Wave: Max 260°C for up to 5 seconds. Ensure the device is positioned so the solder does not wick closer than 2mm to the lens base.

Excessive temperature or time can cause permanent damage to the LED epoxy, leads, or internal die bonds.

7. Application Notes & Design Considerations

7.1 Typical Application Circuits

Each LED in the array should be driven independently with a current-limiting resistor. The resistor value (R) is calculated using the formula: R = (Vcc - VF) / IF, where Vcc is the supply voltage, VF is the forward voltage of the LED (use max value from datasheet for reliability), and IF is the desired forward current (not to exceed the DC rating).

7.2 Thermal Management

Although power dissipation is low, proper thermal design extends lifespan. Ensure adequate spacing on the PCB for heat dissipation. Operating at or near the maximum current (30mA for white) will generate more heat. If the ambient temperature is high, consider derating the operating current.

7.3 ESD Precautions

While the device has built-in Zener protection, standard ESD handling precautions should still be followed during assembly: use grounded workstations, wrist straps, and conductive containers.

8. Frequently Asked Questions (Based on Technical Parameters)

8.1 Can I drive the white LED at 30mA continuously?

Yes, 30mA is the maximum rated DC forward current. However, for optimal longevity and reliability, it is often advisable to operate at a lower current, such as 20mA, especially if thermal conditions are not ideal.

8.2 What is the difference between the D1, D2, D3, D4 white bins?

These bins represent different regions on the CIE 1931 chromaticity diagram, corresponding to slight variations in the correlated color temperature (CCT) and tint of the white light (e.g., cool white with a blueish tint vs. pure white). D1 and D2 are typically cooler/bluer, while D3 and D4 are warmer/yellower, though all fall within a defined white region.

8.3 Is a heatsink required?

For typical indicator applications at or below the recommended drive current, a dedicated heatsink is not required. The PCB itself acts as a heatsink for the leads. The primary thermal management is ensuring the device does not exceed its maximum junction temperature, which is influenced by ambient temperature, drive current, and PCB layout.

8.4 Can I use this LED outdoors?

The datasheet states it is suitable for indoor and outdoor signs. However, for prolonged outdoor use, consider additional environmental protection (conformal coating on the PCB) to guard against moisture, UV radiation, and contaminants, as the LED package itself may not be fully hermetic.

9. Technical Comparison & Trends

9.1 Comparison with SMD Alternatives

Through-hole LEDs like the LTW-404M01H279 offer advantages in prototyping, manual assembly, and applications requiring high mechanical strength or accessibility for replacement. Surface-Mount Device (SMD) LEDs, in contrast, enable higher-density PCB designs, are better suited for automated pick-and-place assembly, and often have superior thermal paths to the PCB.

9.2 Industry Trends

The general trend in indicator lighting is towards higher efficiency (more lumens per watt), which allows for the same brightness at lower currents, reducing power consumption and heat generation. There is also a move towards tighter binning tolerances for color and intensity to ensure visual consistency in multi-indicator applications. While SMD packages dominate new designs, through-hole indicators remain vital for legacy designs, repair markets, and applications where their specific mechanical benefits are required.