Through Hole LED Lamp LTLR42FGAJH79Y Specification - Yellow Green 570nm - 20mA - 52mW - English Technical Document

1. Product Overview

This document details the specifications for a through-hole mounted LED lamp, designed as a Circuit Board Indicator (CBI). The device utilizes a black plastic right-angle holder (housing) that mates with the LED component. This design facilitates easy assembly onto printed circuit boards (PCBs). The primary light source is a solid-state LED, offering advantages in efficiency and longevity.

1.1 Core Advantages

• Ease of Assembly: The design is optimized for straightforward and efficient mounting onto circuit boards.
• Enhanced Contrast: The black housing material improves the visual contrast ratio of the illuminated indicator.
• Solid-State Reliability: Utilizes LED technology for a robust, long-lasting light source with no filaments to break.
• Energy Efficiency: Characterized by low power consumption and high luminous efficacy.
• Environmental Compliance: This is a lead-free product compliant with the RoHS (Restriction of Hazardous Substances) directive.
• Specific Emission: LEDs 1 and 4 emit light in the yellow-green spectrum with a peak wavelength around 570nm, using AllnGaP (Aluminum Indium Gallium Phosphide) technology.
• Moisture Sensitivity: Rated at MSL3 (Moisture Sensitivity Level 3).

1.2 Target Applications

This LED lamp is suitable for a variety of electronic equipment requiring status or indicator lighting. Typical application sectors include:

• Communication Equipment
• Computer Systems and Peripherals
• Consumer Electronics
• Home Appliances

2. Technical Parameter Deep Dive

2.1 Absolute Maximum Ratings

The following ratings must not be exceeded under any conditions, as doing so may cause permanent damage to the device. All values are specified at an ambient temperature (TA) of 25°C.

• Power Dissipation (PD): 52 mW - The maximum total power the device can safely dissipate.
• Peak Forward Current (IFP): 60 mA - This is the maximum instantaneous forward current, permissible only under pulsed conditions (duty cycle ≤ 1/10, pulse width ≤ 0.1ms).
• DC Forward Current (IF): 20 mA - The maximum continuous forward current recommended for normal operation.
• Operating Temperature Range (Topr): -40°C to +85°C - The ambient temperature range within which the device is designed to function.
• Storage Temperature Range (Tstg): -40°C to +100°C - The temperature range for non-operational storage.
• Lead Soldering Temperature: 260°C for a maximum of 5 seconds, measured 2.0mm (0.079 inches) from the body of the component.

2.2 Electrical & Optical Characteristics

These are the typical performance parameters measured at TA=25°C. The values for LEDs 1 and 4 (yellow-green) are provided.

• Luminous Intensity (Iv): Ranges from a minimum of 23 mcd to a maximum of 140 mcd, with a typical value of 80 mcd, measured at IF=20mA. This parameter is binned (see Section 3).
• Viewing Angle (2θ1/2): Approximately 100 degrees. This is the full angle at which the luminous intensity drops to half of its axial (on-center) value.
• Peak Emission Wavelength (λP): Typically 571 nm. This is the wavelength at which the spectral power distribution is at its maximum.
• Dominant Wavelength (λd): Ranges from 565 nm to 571 nm, with a typical value of 569 nm at IF=20mA. This is the single wavelength perceived by the human eye, derived from the CIE chromaticity diagram.
• Spectral Line Half-Width (Δλ): Typically 15 nm. This indicates the spectral purity; a smaller value means a more monochromatic light.
• Forward Voltage (VF): Ranges from 1.6V to 2.6V, with a typical value of 2.1V at IF=20mA.
• Reverse Current (IR): Maximum of 10 μA when a reverse voltage (VR) of 5V is applied. Important Note: The device is not designed for operation in reverse bias; this test condition is for characterization only.

3. Binning System Explanation

To ensure consistency in production, LEDs are sorted into bins based on key optical parameters. This allows designers to select components that meet specific brightness and color requirements.

3.1 Luminous Intensity Binning

LEDs are classified into three intensity bins, measured in millicandelas (mcd) at a forward current of 20mA. The tolerance for each bin limit is ±15%.

• Bin AB: Minimum 23 mcd, Maximum 50 mcd.
• Bin CD: Minimum 50 mcd, Maximum 85 mcd.
• Bin EF: Minimum 85 mcd, Maximum 140 mcd.

3.2 Dominant Wavelength Binning

LEDs are also binned by their dominant wavelength to control color consistency. The tolerance for each bin limit is ±1 nm.

• Bin 1: Minimum 565.0 nm, Maximum 568.0 nm.
• Bin 2: Minimum 568.0 nm, Maximum 571.0 nm.

The bin code for both intensity and wavelength is marked on the product packaging, enabling precise selection for application needs.

4. Performance Curve Analysis

While specific graphical curves are referenced in the datasheet, the following analysis is based on the provided tabular data and standard LED behavior.

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

The typical forward voltage (VF) of 2.1V at 20mA indicates this is a low-voltage LED, typical for AllnGaP technology. The VF will have a negative temperature coefficient, meaning it decreases slightly as the junction temperature increases. The specified range (1.6V to 2.6V) accounts for normal production variance.

4.2 Luminous Intensity vs. Forward Current

Luminous intensity is approximately proportional to the forward current within the recommended operating range (up to 20mA). Exceeding the DC current rating will increase light output non-linearly and generate excessive heat, potentially degrading the LED's lifetime and shifting its color.

4.3 Temperature Characteristics

The luminous intensity of LEDs generally decreases as the junction temperature rises. Although not graphed here, the wide operating temperature range (-40°C to +85°C) implies the device is designed to maintain functionality across harsh environments, though with potentially reduced output at the upper limit. Proper heat sinking via the PCB is crucial for maintaining performance and longevity.

5. Mechanical & Package Information

5.1 Outline and Dimensions

The device uses a through-hole package with a right-angle orientation. Key mechanical notes include:

• All dimensions are provided in millimeters, with tolerances of ±0.25mm unless otherwise specified.
• The holder (housing) is constructed from black plastic rated UL94V-0, indicating it is flame-retardant.
• LEDs 1 and 4 feature a white diffused lens, which helps to broaden the viewing angle and soften the light appearance.

5.2 Polarity Identification

For through-hole LEDs, polarity is typically indicated by lead length (the longer lead is the anode, or positive side) and/or a flat spot or notch on the lens or housing. The datasheet should be consulted for the specific marking on this component. Applying reverse voltage can damage the LED.

6. Soldering & Assembly Guidelines

6.1 Storage Conditions

Due to its MSL3 rating, proper handling is critical to prevent moisture-induced damage during reflow.

• Sealed Package: Store at ≤30°C and ≤70% RH. Use within one year of the pack date.
• Opened Package: For components removed from their moisture barrier bag (MBB), the ambient should be ≤30°C and ≤60% RH.
• Floor Life: Components exposed to ambient air should be IR-reflowed within 168 hours (7 days).
• Extended Storage/Baking: If the MBB has been open for more than 168 hours, a bake at 60°C for at least 48 hours is strongly recommended before the SMT assembly process to drive out absorbed moisture.

6.2 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.
• Do not use the base of the lead frame as a fulcrum to avoid stressing the internal die attach.
• During PCB insertion, use the minimum clinch force necessary.

6.3 Soldering Process

• Maintain a minimum clearance of 2mm from the base of the lens/holder to the solder point.
• Avoid immersing the lens or holder into solder.
• Do not apply external stress to the leads while the LED is hot from soldering.
• Recommended Hand Soldering: Iron temperature ≤ 350°C, soldering time ≤ 3 seconds per lead, applied no closer than 2mm from the epoxy bulb base. This should be performed only once.
• Warning: Excessive temperature or time can deform the lens or cause catastrophic failure. The maximum wave soldering temperature is not equivalent to the holder's heat deflection temperature (HDT).

6.4 Cleaning

If cleaning is required after soldering, use alcohol-based solvents such as isopropyl alcohol (IPA). Avoid harsh or aggressive chemicals that may damage the plastic housing or lens.

7. Application Notes & Design Considerations

7.1 Typical Application Circuits

This LED is typically driven by a constant current source or, more commonly, a current-limiting resistor in series with a voltage supply. The resistor value (R) can be calculated using Ohm's Law: R = (V_supply - VF) / IF. Using the typical VF of 2.1V and IF of 20mA with a 5V supply: R = (5V - 2.1V) / 0.02A = 145 Ohms. A standard 150 Ohm resistor would be suitable, dissipating P = I^2 * R = (0.02)^2 * 150 = 0.06W.

7.2 Design Considerations

• Current Control: Always use a current-limiting device. Connecting directly to a voltage source will cause excessive current flow and immediate failure.
• Thermal Management: Although power dissipation is low (52mW max), ensuring adequate PCB copper area around the leads helps dissipate heat, especially in high ambient temperature applications or when operating near the maximum current.
• Visual Design: The black housing and diffused lens are designed for good contrast and wide viewing angle. Consider the intended viewing angle when positioning the LED on the PCB.
• Bin Selection: For applications requiring uniform brightness or precise color, specify the required intensity (e.g., Bin EF) and wavelength (e.g., Bin 2) bins during procurement.

8. Frequently Asked Questions (Based on Technical Parameters)

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

Peak Wavelength (λP) is the literal highest point on the spectral output curve. Dominant Wavelength (λd) is the single wavelength that the human eye perceives the color to be, calculated from the CIE color coordinates. For a monochromatic source like this LED, they are often very close (571nm vs 569nm typical). Dominant wavelength is more relevant for color specification.

8.2 Can I drive this LED with a 3.3V supply?

Yes. Using the typical VF of 2.1V at 20mA, a series resistor would be: R = (3.3V - 2.1V) / 0.02A = 60 Ohms. Ensure the resistor power rating is sufficient (0.02^2 * 60 = 0.024W).

8.3 Why is there a Peak Forward Current rating much higher than the DC rating?

The 60mA peak rating (under short pulses) allows for brief periods of overdrive to achieve very high brightness for strobe or multiplexing applications. The low duty cycle (≤10%) ensures the average power and junction temperature do not exceed safe limits. For constant illumination, never exceed the 20mA DC rating.

8.4 What does MSL3 mean for my assembly process?

MSL3 indicates the component can absorb damaging levels of moisture from the air after its sealed bag is opened. To prevent "popcorning" (internal delamination) during the high-temperature reflow soldering process, you must either solder it within 168 hours of bag opening or bake it beforehand as described in section 6.1.

9. Technology Background & Trends

9.1 AllnGaP Technology

This LED uses Aluminum Indium Gallium Phosphide (AllnGaP) semiconductor material. This technology is highly efficient for producing light in the amber, yellow, and yellow-green spectrum (roughly 570nm to 620nm). It offers good luminous efficacy and stability compared to older technologies like filtered GaP.

9.2 Through-Hole vs. Surface-Mount Trends

While surface-mount device (SMD) LEDs dominate modern high-volume electronics for their size and assembly speed, through-hole LEDs like this one remain relevant. Their key advantages include superior mechanical strength (resistant to board flex), easier manual prototyping and repair, and often higher allowable power dissipation per package due to longer leads acting as heat sinks. They are commonly found in industrial controls, power supplies, automotive aftermarket products, and devices where reliability under vibration is critical.

9.3 Indicator LED Development

The trend for indicator LEDs continues toward higher efficiency (more light per mA), allowing for lower operating currents and reduced system power. There is also a focus on improving color consistency across production batches through advanced binning and tighter process controls, as evidenced by the detailed bin tables in this datasheet. The use of diffused lenses and contrast-enhancing housings, as seen here, improves readability—a constant design goal.