LTL-R42TBN4D2H229 Blue LED Lamp Datasheet - Through Hole - 20mA - 3.8V - English Technical Document

1. Product Overview

The LTL-R42TBN4D2H229 is a through-hole mounted LED lamp designed for printed circuit board (PCB) applications. It is a component within the Circuit Board Indicator (CBI) family, which utilizes a black plastic right-angle holder (housing) that mates with the LED lamp. This design facilitates easy assembly and is available in configurations that allow for stacking and the creation of horizontal or vertical arrays.

1.1 Core Advantages

• Ease of Assembly: The design is optimized for straightforward circuit board assembly processes.
• Enhanced Contrast: The black housing material improves the visual contrast ratio of the illuminated indicator.
• Material Compliance: The product features low halogen content.
• Compatibility: It is compatible with integrated circuits (I.C.) and has low current requirements.
• Optical Performance: The lamp uses a white diffused lens for a uniform light appearance.
• Efficiency: It offers low power consumption and high luminous efficiency.
• Light Source: The T-1 sized lamp utilizes an InGaN (Indium Gallium Nitride) semiconductor chip emitting blue light with a peak wavelength around 470nm.

1.2 Target Applications

This LED is suitable for a broad range of electronic equipment, including:

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

2. Technical Parameter Deep Dive

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): 117 mW maximum. This is the total power the device can safely dissipate as heat.
• Peak Forward Current (IFP): 100 mA maximum. This current can only be applied under pulsed conditions (duty cycle ≤ 1/10, pulse width ≤ 0.1ms).
• DC Forward Current (IF): 20 mA maximum. This is the recommended continuous operating current.
• Operating Temperature Range: -40°C to +85°C. The device is designed to function within this environmental temperature range.
• Storage Temperature Range: -55°C to +100°C. The device can be stored within this range when not in operation.
• Lead Soldering Temperature: 260°C for a maximum of 5 seconds, measured at a distance of 2.0mm (0.079 inches) from the body of the component. This is critical for wave or hand soldering processes.

2.2 Electrical & Optical Characteristics

These are the typical performance parameters measured at TA=25°C and IF=20mA, unless otherwise stated.

• Luminous Intensity (Iv): 180 mcd (minimum), 400 mcd (typical), 880 mcd (maximum). This is the measure of perceived light power emitted. The actual Iv value for a specific unit is determined by its bin code (see Section 4). A ±15% testing tolerance is applied to these bin limits.
• Viewing Angle (2θ1/2): 60 degrees (typical). This is the full angle at which the luminous intensity is half the value measured on the central axis.
• Peak Emission Wavelength (λP): 468 nm (typical). This is the wavelength at which the spectral emission is strongest.
• Dominant Wavelength (λd): 460 nm (minimum), 470 nm (typical), 475 nm (maximum). This is the single wavelength that best represents the perceived color of the light, derived from the CIE chromaticity diagram. Units are binned accordingly (see Section 4).
• Spectral Line Half-Width (Δλ): 25 nm (typical). This indicates the spectral purity or bandwidth of the emitted light.
• Forward Voltage (VF): 3.2 V (minimum), 3.8 V (typical). This is the voltage drop across the LED when operating at the specified forward current.
• Reverse Current (IR): 10 μA maximum when a reverse voltage (VR) of 5V is applied. Important: This device is not designed for operation under reverse bias; this test condition is for characterization only.

3. Binning System Explanation

To ensure consistency in applications, LEDs are sorted (binned) based on key optical parameters.

3.1 Luminous Intensity Binning

LEDs are classified into bins based on their measured luminous intensity at IF=20mA. The bin code is marked on the packing bag.

• H: 180 mcd to 240 mcd
• J: 240 mcd to 310 mcd
• K: 310 mcd to 400 mcd
• L: 400 mcd to 520 mcd
• M: 520 mcd to 680 mcd
• N: 680 mcd to 880 mcd

Note: Tolerance on each bin limit is ±15%.

3.2 Dominant Wavelength (Hue) Binning

LEDs are also binned by their dominant wavelength to control color consistency.

• B07: 460.0 nm to 465.0 nm
• B08: 465.0 nm to 470.0 nm
• B09: 470.0 nm to 475.0 nm

Note: Tolerance on each bin limit is ±1 nm.

4. Performance Curve Analysis

The datasheet includes typical characteristic curves which are essential for design engineers.

• Relative Luminous Intensity vs. Forward Current: This curve shows how light output increases with drive current, typically exhibiting a sub-linear relationship at higher currents.
• Relative Luminous Intensity vs. Ambient Temperature: This curve demonstrates the thermal quenching effect, where light output decreases as the junction temperature rises. Understanding this is critical for thermal management in high-temperature or high-current applications.
• Forward Voltage vs. Forward Current: This depicts the diode's I-V characteristic, showing the exponential relationship and the typical operating voltage at the recommended 20mA current.
• Spectral Distribution: A graph showing the relative radiant power as a function of wavelength, centered around the 468nm peak, with the defined half-width.

5. Mechanical & Packaging Information

5.1 Outline Dimensions

The component features a right-angle through-hole design. Key dimensional notes include:

• All dimensions are provided in millimeters, with inches in parentheses.
• Standard tolerance is ±0.25mm (±0.010\") unless otherwise specified.
• The housing material is black plastic.
• The LED lamps (LED1 and LED2 in the drawing) are blue with a white diffused lens.

5.2 Packaging Specification

The LEDs are supplied on tape-and-reel for automated assembly.

• Carrier Tape: Made of black conductive polystyrene alloy, 0.50mm ±0.06mm thick.
• Reel: Standard 13-inch reel containing 350 pieces.
• Carton Packing:
  • 2 reels (700 pieces total) are packed with a humidity indicator card and 2 desiccants in one Moisture Barrier Bag (MBB).
  • 1 MBB is packed in 1 inner carton.
  • 10 inner cartons (7,000 pieces total) are packed in 1 outer carton.

6. Soldering & Assembly Guidelines

6.1 Storage

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 longer storage outside the original packaging, use a sealed container with desiccant or a nitrogen desiccator.

6.2 Cleaning

If cleaning is necessary, use alcohol-based solvents such as isopropyl alcohol.

6.3 Lead Forming

If leads need to be bent, do so 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. Lead forming must be performed at room temperature and before the soldering process.

6.4 Soldering Process

Critical Rule: Maintain a minimum distance of 2mm from the base of the lens/holder to the soldering point. Never immerse the lens/holder into solder.

• Soldering Iron: Maximum temperature 350°C. Maximum soldering time 3 seconds per lead (one time only).
• Wave Soldering:
  • Pre-heat: Maximum 120°C for up to 100 seconds.
  • Solder Wave: Maximum 260°C.
  • Soldering Time: Maximum 5 seconds.
  • Dipping Position: No lower than 2mm from the base of the epoxy bulb.

Warning: Excessive temperature or time can deform the lens or cause catastrophic LED failure. Avoid applying mechanical stress to the leads during soldering while the LED is hot.

7. Application Design Considerations

7.1 Drive Circuit Design

LEDs are current-operated devices. To ensure uniform brightness when connecting multiple LEDs in parallel, it is strongly recommended to use a individual current-limiting resistor in series with each LED (Circuit Model A). Avoid connecting LEDs directly in parallel without individual resistors (Circuit Model B), as slight variations in the forward voltage (VF) characteristic between LEDs will cause significant current imbalance, leading to uneven brightness and potential over-current in some devices.

7.2 ESD (Electrostatic Discharge) Protection

This LED is susceptible to damage from electrostatic discharge or power surges. Implement standard ESD prevention measures during handling and assembly:

• Use conductive wrist straps and grounded workstations.
• Employ ionizers to neutralize static charge in the work area.
• Store and transport components in conductive or anti-static packaging.

8. Technical Comparison & Trends

8.1 Design Advantages

The through-hole design of the LTL-R42TBN4D2H229 offers robustness and ease of manual prototyping compared to surface-mount devices (SMDs). The integrated black right-angle holder provides mechanical stability, improves contrast, and simplifies board layout for status indicators. The binning system for intensity and wavelength provides designers with predictable performance for applications requiring visual consistency.

8.2 Industry Context

While surface-mount technology (SMT) dominates high-volume automated production, through-hole components like this one remain vital for applications requiring higher mechanical strength, easier manual assembly for low-volume or repair scenarios, and in environments with significant thermal or mechanical stress. The use of InGaN technology for blue emission represents a mature and reliable semiconductor process. The inclusion of detailed soldering and handling guidelines reflects the industry's focus on reliability and yield during the manufacturing process.

9. Frequently Asked Questions (FAQ)

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

Peak Wavelength (λP) is the single wavelength where the LED emits the most optical power. Dominant Wavelength (λd) is calculated from the CIE color coordinates and represents the perceived color of the light. For a monochromatic source like a blue LED, they are often close, but λd is the relevant parameter for color matching in applications.

9.2 Can I drive this LED with a constant voltage source?

It is not recommended. The forward voltage (VF) has a tolerance and varies with temperature. Driving with a constant voltage can lead to large variations in current and thus brightness. Always use a current-limiting method, such as a series resistor with a voltage source or a constant current driver.

9.3 Why is there a minimum distance specified for soldering?

The 2mm minimum distance prevents excessive heat from traveling up the lead and damaging the internal semiconductor die or the epoxy lens material, which can crack or become opaque from thermal shock.

9.4 How do I interpret the bin codes for my order?

Specify the required Iv (e.g., 'K' bin: 310-400 mcd) and λd (e.g., 'B08' bin: 465-470 nm) bin codes when ordering to ensure you receive LEDs with the optical characteristics suitable for your design. The bin code is marked on the packaging.

10. Practical Application Example

10.1 Designing a Panel Status Indicator

Scenario: A designer needs a bright, consistent blue power-on indicator for an industrial control panel. Multiple units must have identical appearance.

1. Component Selection: Choose the LTL-R42TBN4D2H229 for its right-angle viewing, high contrast black housing, and available brightness.
2. Binning: Specify a narrow intensity bin (e.g., 'L' or 'M') and a specific hue bin (e.g., 'B08') to ensure color and brightness uniformity across all panels.
3. Circuit Design: The panel uses a 12V rail. For an LED with a typical VF of 3.8V at 20mA, calculate the series resistor: R = (V_supply - VF) / IF = (12V - 3.8V) / 0.020A = 410 Ω. Use a standard 430 Ω, 1/4W resistor. Each indicator LED gets its own resistor.
4. PCB Layout: Place the LED footprint respecting the right-angle orientation. Ensure the solder pads are at least 2mm away from the edge of the mounting hole for the LED body.
5. Assembly: Follow the wave soldering profile specified, ensuring the pre-heat and wave contact times/temperatures are not exceeded to protect the LED.

This systematic approach, guided by the datasheet parameters, ensures a reliable and visually consistent end product.