LTL-R42FTGBH229 LED Indicator Datasheet - Right Angle T-1 Package - Green 525nm & Blue 470nm - 20mA - English Technical Document

1. Product Overview

The LTL-R42FTGBH229 is a dual-color, right-angle through-hole LED indicator designed for printed circuit board (PCB) mounting. It belongs to the Circuit Board Indicator (CBI) product family, featuring a black plastic housing that provides high contrast for improved visibility. The device integrates two distinct T-1 sized LED lamps: one emitting green light with a peak wavelength of 525nm and the other emitting blue light with a peak wavelength of 470nm. This configuration allows for status indication using two different colors from a single component footprint.

1.1 Core Advantages

• Ease of Assembly: The right-angle design and stackable housing simplify PCB assembly and layout, especially in space-constrained applications.
• Enhanced Contrast: The matte black housing significantly improves the contrast ratio, making the LED light more distinct and readable under various ambient lighting conditions.
• Energy Efficiency: The device operates at low power consumption while delivering high luminous efficiency, making it suitable for power-sensitive designs.
• Environmental Compliance: This is a lead-free product fully compliant with RoHS (Restriction of Hazardous Substances) directives.
• Automated Handling: The product is supplied in tape and reel packaging, making it compatible with high-speed automated pick-and-place assembly equipment.

1.2 Target Applications

This LED indicator is versatile and finds use across multiple electronics sectors:

• Communication Equipment: Status lights for routers, switches, modems, and network interface cards.
• Computer Peripherals: Power, activity, and mode indicators on motherboards, external drives, and keyboards.
• Consumer Electronics: Indicator lights in audio/video equipment, home appliances, and gaming devices.
• Industrial Controls: Machine status panels, control system interfaces, and instrumentation.

2. In-Depth Technical Parameter Analysis

2.1 Absolute Maximum Ratings

Operating the device beyond these limits may cause permanent damage.

• Power Dissipation (P_D): 70 mW (for both Green and Blue LEDs). This defines the maximum power the LED chip can dissipate as heat.
• Peak Forward Current (I_FP): 60 mA. This is the maximum allowable pulsed current, with a duty cycle ≤ 1/10 and pulse width ≤ 10µs. It is used for brief, high-intensity flashes.
• DC Forward Current (I_F): 20 mA. This is the recommended continuous operating current for reliable long-term performance.
• Operating Temperature Range (T_opr): -30°C to +85°C. The device is guaranteed to function within this ambient temperature range.
• Storage Temperature Range (T_stg): -40°C to +100°C. The device can be stored safely within these limits when not powered.

2.2 Electro-Optical Characteristics

All parameters are specified at an ambient temperature (T_A) of 25°C and a forward current (I_F) of 10mA, unless otherwise noted.

• Luminous Intensity (I_V): A key measure of brightness.
  • Green LED: Typical value is 420 mcd (millicandela), with a range from 180 mcd (Min) to 880 mcd (Max).
  • Blue LED: Typical value is 140 mcd, with a range from 65 mcd (Min) to 310 mcd (Max).
• Viewing Angle (2θ_1/2): 100 degrees for both colors. This is the full angle at which the luminous intensity drops to half of its peak (axial) value. A 100-degree angle provides a wide viewing cone.
• Peak Wavelength (λ_P): The wavelength at which the emitted optical power is greatest.
  • Green: 526 nm (typical).
  • Blue: 468 nm (typical).
• Dominant Wavelength (λ_d): The single wavelength perceived by the human eye that defines the color.
  • Green: 525 nm (typical), range 516-535 nm.
  • Blue: 470 nm (typical), range 460-475 nm.
• Spectral Line Half-Width (Δλ): 35 nm for both. This indicates the spectral purity; a smaller value means a more monochromatic color.
• Forward Voltage (V_F): The voltage drop across the LED when conducting the specified current.
  • Green: 2.9V (typical), range 2.4-3.3V.
  • Blue: 3.1V (typical), range 2.5-3.6V.
• Reverse Current (I_R): 10 µA (max) at a reverse voltage (V_R) of 5V. Important: This device is not designed for reverse-bias operation; this parameter is for test purposes only.

3. Binning System Explanation

To ensure color and brightness consistency in production, LEDs are sorted into bins. The LTL-R42FTGBH229 uses separate binning for luminous intensity and dominant wavelength.

3.1 Green LED Binning

• Luminous Intensity Bins (@10mA):
  • HJ: 180 - 310 mcd
  • KL: 310 - 520 mcd
  • MN: 520 - 880 mcd
• Dominant Wavelength Bins (@10mA):
  • G09: 516.0 - 520.0 nm
  • G10: 520.0 - 527.0 nm
  • G11: 527.0 - 535.0 nm

3.2 Blue LED Binning

• Luminous Intensity Bins (@10mA):
  • DE: 65 - 110 mcd
  • FG: 110 - 180 mcd
  • HJ: 180 - 310 mcd
• Dominant Wavelength Bins (@10mA):
  • B07: 460.0 - 465.0 nm
  • B08: 465.0 - 470.0 nm
  • B09: 470.0 - 475.0 nm

Note: Each bin limit has a tolerance: ±15% for luminous intensity and ±1 nm for dominant wavelength. Specific bin combinations for a given order should be confirmed with the supplier.

4. Mechanical and Packaging Information

4.1 Outline Dimensions

The device features a right-angle black plastic housing. Key dimensional notes include:

• All dimensions are in millimeters, with a general tolerance of ±0.25mm unless specified otherwise.
• The housing material is black plastic.
• LED1 is the green emitter with a green diffused lens; LED2 is the blue emitter with a blue diffused lens.
• Detailed dimensional drawings are provided in the source datasheet, specifying pin length, housing size, and lens position.

4.2 Packaging Specification

The product is supplied for automated assembly:

• Tape and Reel: Components are loaded into embossed carrier tape made of black conductive polystyrene alloy (0.50mm ±0.06mm thick).
• Reel Capacity: 350 pieces per standard 13-inch (330mm) reel.
• Carton Packing:
  1. One reel is packed with a desiccant and humidity indicator card inside a Moisture Barrier Bag (MBB).
  2. Two MBBs (700 pieces total) are packed in one Inner Carton.
  3. Ten Inner Cartons (7,000 pieces total) are packed in one Outer Carton for shipment.

5. Soldering and Assembly Guidelines

Proper handling is critical to prevent damage to the LED or its plastic housing.

5.1 Lead Forming

• Bending must be performed before soldering and at room temperature.
• The bend point must be at least 3mm from the base of the LED lens/housing.
• Do not use the base of the lead frame as a fulcrum. Apply minimal clinch force during PCB insertion.

5.2 Soldering Processes

A minimum clearance of 2mm must be maintained between the solder point and the base of the lens/holder. Never immerse the lens into solder.

• Manual Soldering Iron:
  • Iron Temperature: ≤ 350°C
  • Soldering Time: ≤ 3 seconds per joint
  • Position: >2mm from lens base
• Wave Soldering:
  • Pre-heat Temperature: ≤ 120°C
  • Pre-heat Time: ≤ 100 seconds
  • Solder Wave Temperature: ≤ 260°C
  • Soldering Time: ≤ 5 seconds
  • Dipping Depth: >2mm from lens base
• Reflow Soldering: A specific reflow profile is referenced, detailing preheat, soak, and peak temperature zones. The profile must ensure the body temperature does not exceed the maximum ratings.

5.3 Storage and Cleaning

• Storage: Store in an environment not exceeding 30°C and 70% relative humidity (RH). LEDs removed from their original moisture barrier bag should be used within three months. For longer storage, use a sealed container with desiccant or a nitrogen ambient.
• Cleaning: Use only alcohol-based solvents like isopropyl alcohol (IPA). Avoid aggressive or ultrasonic cleaning that may stress the component.

6. Application Design Considerations

6.1 Current Limiting

An external current-limiting resistor is mandatory for safe operation. The resistor value (R_series) can be calculated using Ohm's Law: R_series = (V_supply - V_F) / I_F. Use the maximum V_F from the datasheet for a conservative design. For a 5V supply and the blue LED (max V_F=3.6V @20mA), R_series = (5 - 3.6) / 0.02 = 70 Ω. A standard 68 Ω or 75 Ω resistor would be suitable. Always verify power dissipation in the resistor (P = I²R).

6.2 Thermal Management

While the power dissipation is low (70mW), proper PCB layout aids longevity. Ensure adequate copper area around the LED pins to act as a heat sink. Avoid placing the LED near other significant heat sources.

6.3 Optical Design

The black housing provides built-in contrast enhancement. For applications requiring light piping or additional diffusion, ensure the chosen material is compatible with the LED's viewing angle and does not cause excessive optical loss.

7. Technical Comparison and Differentiation

The LTL-R42FTGBH229 offers specific advantages in its category:

• Dual-Color in Single Housing: Saves PCB space compared to mounting two separate single-color indicators.
• Right-Angle Design: Ideal for applications where the PCB is mounted parallel to the viewing surface (e.g., front panels of equipment), offering a direct side-view.
• Standard T-1 Lamps: Utilizes common, proven LED lamp packages, ensuring reliability and broad compatibility.
• Wide Viewing Angle: The 100-degree viewing angle ensures visibility from a broad range of positions.

8. Frequently Asked Questions (FAQ)

Q1: Can I drive the Green and Blue LEDs simultaneously at their full 20mA each?
A1: Electrically, yes, as they are separate dice. However, you must consider the total power dissipation on the small housing. Driving both at 20mA (V_F~3V) results in ~120mW total dissipation, which exceeds the 70mW per-die rating. For continuous simultaneous operation, it is advisable to derate the current, e.g., to 10-15mA each, to stay within thermal limits.

Q2: What is the difference between Peak Wavelength and Dominant Wavelength?
A2: Peak Wavelength (λ_P) is the physical peak of the emission spectrum. Dominant Wavelength (λ_d) is calculated from the CIE color coordinates and represents the single wavelength the human eye perceives the color to be. For LEDs, λ_d is often the more relevant parameter for color specification.

Q3: How do I interpret the bin codes when ordering?
A3: The bin codes (e.g., KL-G10 for Green) define the brightness and color range of the LEDs you will receive. For consistent appearance in a product, specifying tighter bins (e.g., a single bin for both parameters) is crucial. Consult with the supplier for available bin combinations.

Q4: Is this LED suitable for outdoor use?
A4: The datasheet states it is good for "indoor and outdoor sign" applications. However, for harsh outdoor environments with direct UV exposure, wide temperature swings, and moisture, additional design considerations are needed, such as conformal coating on the PCB and ensuring the housing material is UV-stable. The operating temperature range (-30°C to +85°C) supports many outdoor conditions.

9. Operational Principle

Light Emitting Diodes (LEDs) are semiconductor devices that emit light through electroluminescence. When a forward voltage exceeding the diode's junction potential is applied, electrons and holes recombine in the active region of the semiconductor material (InGaN for green and blue LEDs). This recombination releases energy in the form of photons (light). The specific wavelength (color) of the emitted light is determined by the bandgap energy of the semiconductor material. The plastic lens serves to focus the light, protect the semiconductor die, and provide color diffusion.

10. Industry Trends

While discrete through-hole indicators remain vital for legacy designs and specific applications requiring high reliability and manual assembly, the industry trend is strongly towards surface-mount device (SMD) LEDs. SMDs offer smaller footprints, lower profiles, better suitability for fully automated assembly, and often improved thermal performance. However, right-angle through-hole LEDs like the LTL-R42FTGBH229 maintain relevance in applications requiring robust mechanical mounting, high visibility from the board edge, or where through-hole connections are preferred for mechanical strength. The integration of multiple colors or functions into a single package continues to be a development focus to save space and simplify assembly.