LTL-R42NM1H229 LED Lamp Datasheet - Through Hole - Yellow/Green - 20mA - 52mW - English Technical Document

1. Product Overview

The LTL-R42NM1H229 is a through-hole LED lamp designed as a Circuit Board Indicator (CBI). It consists of a black plastic right-angle holder (housing) that mates with two distinct LED lamps. This component is engineered for straightforward assembly onto printed circuit boards (PCBs), offering a reliable and cost-effective solution for status indication.

1.1 Core Advantages

• Ease of Assembly: The design is optimized for simple and efficient mounting on circuit boards.
• Enhanced Contrast: The black housing material provides a high contrast ratio, improving the visibility of the illuminated LEDs.
• Energy Efficiency: Features low power consumption and high luminous efficiency.
• Environmental Compliance: This is a lead-free product compliant with RoHS (Restriction of Hazardous Substances) directives.
• Dual Color Option: Integrates two distinct LED colors: a standard yellow (approx. 589nm) and a green/yellow-green (approx. 569nm).

1.2 Target Applications

This LED lamp is suitable for a broad range of electronic equipment requiring clear status or indicator lights. Primary application sectors include:

• Communication Equipment
• Computer and Peripheral Devices
• Consumer Electronics
• Industrial Control Systems

2. Technical Parameter Deep Dive

This section provides a detailed, objective analysis of the key electrical, optical, and thermal parameters specified for the LTL-R42NM1H229 LED lamp.

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 (P_D): 52 mW per LED. This is the maximum power the LED can dissipate continuously at an ambient temperature (T_A) of 25°C. Exceeding this limit risks thermal damage.
• Peak Forward Current (I_FP): 60 mA. This current is permissible only under pulsed conditions (duty cycle ≤ 1/10, pulse width ≤ 0.1ms). It should not be used for DC operation.
• DC Forward Current (I_F): 20 mA. This is the recommended maximum continuous forward current for reliable long-term operation.
• Operating Temperature Range: -30°C to +85°C. The device is designed to function within this ambient temperature range.
• Storage Temperature Range: -40°C to +100°C. The device can be stored safely within these limits when not in operation.
• Lead Soldering Temperature: 260°C for a maximum of 5 seconds, measured 2.0mm (0.079\") from the LED body. This defines the thermal profile tolerance during manual or wave soldering processes.

2.2 Electrical & Optical Characteristics

These are the typical performance parameters measured at T_A=25°C and I_F=10mA, unless otherwise stated.

• Luminous Intensity (I_V): A key measure of brightness.
  • Yellow LED: Typical 11 mcd, ranging from 3.8 mcd (Min) to 30 mcd (Max).
  • Green/Yellow-Green LED: Typical 19 mcd, ranging from 8.7 mcd (Min) to 50 mcd (Max).
  • Note: Measurement includes a ±15% testing tolerance. The green LED exhibits higher typical brightness.
• Viewing Angle (2θ_1/2): 100 degrees for both colors. This wide viewing angle ensures the LED is visible from a broad range of positions relative to its axis.
• Peak Wavelength (λ_P): The wavelength at which the emitted light intensity is highest.
  • Yellow: 591 nm
  • Green: 572 nm
• Dominant Wavelength (λ_d): Represents the perceived color of the light.
  • Yellow: 589 nm (range 584-594 nm)
  • Green/Yellow-Green: 569 nm (range 566-574 nm)
• Spectral Line Half-Width (Δλ): Approximately 15 nm for both colors, indicating a relatively narrow, pure color emission.
• Forward Voltage (V_F): Typically 2.0V, with a maximum of 2.5V at I_F=10mA. This low voltage is compatible with common low-voltage logic circuits.
• Reverse Current (I_R): Maximum 100 μA at V_R=5V. Critical Note: The device is not designed for operation under reverse bias; this parameter is for test purposes only. Applying reverse voltage in-circuit can damage the LED.

3. Binning System Explanation

The product uses a binning system to categorize LEDs based on their luminous intensity (I_V) and hue (dominant wavelength). This ensures consistency within a production batch.

3.1 Luminous Intensity Binning

LEDs are sorted into bins (A, B, C, D) based on their measured light output at 10mA. The specification notes a tolerance of ±15% for each I_V bin limit. This means LEDs within the same bin will have closely matched brightness levels, which is crucial for applications requiring uniform appearance across multiple indicators.

3.2 Hue (Wavelength) Binning

LEDs are further categorized by their dominant wavelength. The tolerance for each hue bin is ±1nm. This tight control ensures minimal color variation between individual LEDs of the same nominal color (yellow or green), which is important for aesthetic consistency and color-coded indicator systems.

The bin table (e.g., codes like L2, L3, H06, 3ST) correlates specific combinations of luminous intensity and hue bins to final product codes (A, B, C, D), allowing for precise selection based on application requirements.

4. Performance Curve Analysis

While the PDF references typical characteristic curves, standard LED behavior can be inferred:

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

LEDs are diodes and exhibit a non-linear I-V relationship. The forward voltage (V_F) has a negative temperature coefficient, meaning it decreases slightly as the junction temperature increases. The specified V_F of ~2.0-2.5V at 10mA is a key parameter for designing the current-limiting resistor in the drive circuit.

4.2 Luminous Intensity vs. Forward Current

The light output (I_V) is approximately proportional to the forward current (I_F) within the recommended operating range (up to 20mA). Driving the LED above this current will increase brightness but also power dissipation and junction temperature, potentially reducing lifespan and causing color shift.

4.3 Temperature Dependence

LED performance is temperature-sensitive. Luminous intensity typically decreases as the junction temperature rises. The specified operating temperature range of -30°C to +85°C defines the ambient conditions under which the published optical characteristics are valid. Operation at higher temperatures will result in reduced light output.

5. Mechanical & Packaging Information

5.1 Outline Dimensions

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

• All dimensions are in millimeters, with a default tolerance of ±0.25mm unless specifically noted otherwise on the dimensioned drawing.
• The housing material is black plastic.
• LED1 is the green/yellow-green color with a matching green diffused lens.
• LED2 is the yellow color with a matching yellow diffused lens.

Note: The exact dimensional drawing is referenced in the datasheet but not reproduced in text form here. Designers must refer to the original drawing for precise placement and footprint details.

5.2 Polarity Identification

For through-hole LEDs, the cathode is typically identified by a flat edge on the LED lens, a shorter lead, or a marking on the housing. The datasheet's dimensional drawing should clearly indicate the polarity. Correct polarity is essential; reverse connection will prevent illumination and may damage the device if reverse voltage exceeds 5V.

5.3 Packing Specification

The product is supplied in packaging suitable for automated assembly or manual handling. The packing specification details the quantity per reel, tube, or tray, and the orientation of the components within the packaging to facilitate pick-and-place machines or prevent damage during transport and storage.

6. Soldering & Assembly Guidelines

Proper handling is critical to ensure reliability and prevent damage.

6.1 Storage Conditions

For extended storage outside the original moisture-barrier bag, it is recommended to store LEDs at ≤30°C and ≤70% relative humidity. If removed from original packaging, use within three months. For longer storage, use a sealed container with desiccant or a nitrogen ambient.

6.2 Cleaning

If cleaning is necessary, use only alcohol-based solvents such as isopropyl alcohol. Avoid aggressive or unknown chemical cleaners that may damage the plastic lens or housing.

6.3 Lead Forming

If leads need to be bent, this must be done before soldering, 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 mechanical stress on the leads or epoxy seal.

6.4 Soldering Parameters

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

• Soldering Iron: Maximum temperature 350°C. Maximum contact time 3 seconds per lead. Perform only once.
• Wave Soldering:
  • Pre-heat: Max 120°C for up to 100 seconds.
  • Solder Wave: Max 260°C.
  • Soldering Time: Max 5 seconds.
  • Dipping Position: No lower than 2mm from the lens base.
• Warning: Excessive temperature or time can melt the plastic lens, degrade the epoxy, or cause catastrophic failure of the semiconductor junction.

7. Application Design Recommendations

7.1 Drive Circuit Design

LEDs are current-driven devices. To ensure stable operation and longevity, a current-limiting resistor must be used in series with each LED. The resistor value (R) is calculated using Ohm's Law: R = (V_supply - V_F) / I_F, where V_F is the LED forward voltage (use typical or max value for design margin) and I_F is the desired forward current (≤20mA).

Circuit Model A (Recommended): Each LED has its own dedicated current-limiting resistor. This provides the best brightness uniformity and individual current control, as it compensates for minor variations in the I-V characteristics of each LED.

Circuit Model B (Not Recommended for Uniformity): Multiple LEDs connected in parallel with a single shared resistor. This can lead to significant differences in brightness between LEDs due to natural variances in their forward voltage. One LED with a slightly lower V_F will draw more current and appear brighter, potentially leading to current hogging and uneven wear.

7.2 ESD (Electrostatic Discharge) Protection

LEDs are sensitive to electrostatic discharge. Precautions must be taken during handling and assembly:

• Operators should wear grounded wrist straps or anti-static gloves.
• All workstations, tools, and equipment must be properly grounded.
• Use ionizers to neutralize static charge that may accumulate on the plastic lens.
• Implement an ESD training and certification program for personnel.

7.3 Thermal Management

While the power dissipation is low (52mW per LED), ensuring the device operates within its specified temperature range is vital for maintaining luminous output and lifespan. Avoid placing the LED near other heat-generating components. Adequate spacing on the PCB allows for some natural convection cooling.

8. Technical Comparison & Differentiation

The LTL-R42NM1H229 offers specific advantages in its niche:

• Integrated Dual Color: The inclusion of two distinct, common indicator colors (yellow and green/yellow-green) in one compact housing saves board space compared to using two separate single-color LEDs.
• Right-Angle Design: The right-angle housing directs light parallel to the PCB surface, which is ideal for front-panel or edge-lit indicator applications where the viewing direction is from the side, not above.
• Black Housing: Provides superior contrast when the LED is off, making the illuminated state more pronounced, especially in bright ambient light conditions.
• Standard Through-Hole Package: Offers mechanical robustness and ease of manual soldering for prototyping or low-volume production, compared to surface-mount devices which require more precise assembly processes.

9. Frequently Asked Questions (Based on Technical Parameters)

Q1: Can I drive this LED at 30mA for extra brightness?
A: No. The Absolute Maximum Rating for DC forward current is 20mA. Operating at 30mA exceeds this rating, which will significantly increase junction temperature, accelerate lumen depreciation, and likely cause premature failure. Always stay within the recommended operating conditions.

Q2: The forward voltage is listed as 2.0V (Typ.) to 2.5V (Max.). Which value should I use for my current-limiting resistor calculation?
A: For a robust design that ensures the current never exceeds the maximum rating even with component tolerances, use the maximum V_F value (2.5V) in your calculation. This guarantees that the actual current will be at or below your target even if the LED's V_F is at the low end of its range.

Q3: What is the difference between Peak Wavelength and Dominant Wavelength?
A: Peak Wavelength (λ_P) is the physical wavelength where the spectral power output is highest. Dominant Wavelength (λ_d) is a calculated value based on human color perception (CIE chromaticity diagram); it's the wavelength of a pure monochromatic light that would appear to have the same color as the LED. λ_d is more relevant for describing the perceived color.

Q4: Can I use this LED outdoors?
A: The datasheet states it is suitable for indoor and outdoor signs. However, for harsh outdoor environments with direct exposure to UV, moisture, and wide temperature swings, additional design considerations are needed, such as conformal coating on the PCB, a protective enclosure, and verifying performance at temperature extremes.

10. Practical Design & Usage Case

Scenario: Designing a dual-status indicator for a network router.
The LTL-R42NM1H229 is ideal. The green LED can indicate \"Power On/System Normal,\" while the yellow LED can indicate \"Network Activity\" or \"Warning.\"

Implementation:
1. Place the component on the PCB near the front panel.
2. Design two independent drive circuits, each with a current-limiting resistor calculated for a 15mA drive current (well within the 20mA limit) using a 5V supply: R = (5V - 2.5V) / 0.015A ≈ 167Ω (use a standard 180Ω or 150Ω resistor).
3. Connect the green LED's anode to a GPIO pin set high for \"Normal\" state.
4. Connect the yellow LED's anode to a different GPIO pin that toggles with data activity.
5. Ensure the PCB layout maintains the 2mm solder-to-lens clearance.
6. During assembly, follow the ESD, lead-forming, and soldering guidelines precisely.

This results in a clean, professional, and reliable status indication system using a single component footprint.

11. Operating Principle Introduction

Light Emitting Diodes (LEDs) are semiconductor devices that emit light through electroluminescence. When a forward voltage is applied across the p-n junction, electrons from the n-type material recombine with holes from the p-type material in the active region. This recombination process releases energy in the form of photons (light). The specific color (wavelength) of the emitted light is determined by the energy bandgap of the semiconductor materials used in the construction of the LED chip. The yellow and green colors in this device are achieved using different semiconductor material compositions (e.g., AlInGaP for yellow, InGaN for green). The diffused plastic lens over the chip serves to spread the light, creating the wide 100-degree viewing angle.

12. Technology Trends

The through-hole LED lamp remains a staple in electronics for its simplicity and durability, particularly in applications requiring high mechanical strength or where manual assembly is prevalent. The general industry trend, however, is toward surface-mount device (SMD) LEDs, which offer smaller footprints, lower profile, and compatibility with high-speed automated pick-and-place assembly lines, reducing manufacturing costs for high-volume products. Furthermore, advancements in LED chip technology continue to improve luminous efficacy (more light output per watt of electrical input), allowing for lower drive currents to achieve the same brightness, which improves energy efficiency and thermal performance. The principles of careful current control, thermal management, and ESD protection remain universally critical across all LED package types.