3.1mm Amber Diffused AlInGaP LED Lamp - Luminous Intensity 140-240mcd @20mA - Forward Voltage 2.4V - English Technical Datasheet

1. Product Overview

This document details the specifications for a high-efficiency, through-hole mounted LED lamp. The device is designed for general-purpose indicator applications, offering a balance of performance, reliability, and ease of use. Its primary function is to provide a clear, visible light signal in electronic equipment.

The core advantages of this component include its high luminous intensity output relative to its low power consumption, making it an energy-efficient choice. The package is compatible with standard printed circuit board (PCB) mounting processes and is designed to be driven by low-current circuits, often interfacing directly with integrated circuits (ICs) without the need for complex driver stages. The diffused lens provides a wide, uniform viewing angle, enhancing visibility from various positions.

The target market encompasses a broad range of consumer and industrial electronics where reliable status indication is required. This includes, but is not limited to, power indicators, mode selectors, and operational status lights in appliances, communication devices, and office equipment.

2. In-Depth Technical Parameter Analysis

2.1 Absolute Maximum Ratings

These ratings define the stress limits beyond which permanent damage to the device may occur. Operation under or at these limits is not guaranteed and should be avoided in reliable design.

• Power Dissipation (Pd): 75 mW. This is the maximum amount of power the device can dissipate as heat at an ambient temperature (T_A) of 25°C. Exceeding this can lead to thermal runaway and failure.
• DC Forward Current (I_F): 30 mA. The maximum continuous current that can be passed through the LED.
• Peak Forward Current: 60 mA, but only under pulsed conditions (1/10 duty cycle, 0.1ms pulse width). This allows for brief moments of higher brightness, such as in blinking applications.
• Derating: The DC forward current must be linearly reduced by 0.4 mA for every degree Celsius the ambient temperature rises above 50°C. This is critical for ensuring longevity in elevated temperature environments.
• Reverse Voltage (V_R): 5 V. Applying a reverse bias voltage higher than this can cause immediate and catastrophic failure of the LED junction.
• Operating & Storage Temperature: -40°C to +100°C. The device is rated for industrial temperature ranges.
• Lead Soldering Temperature: 260°C for 5 seconds, measured 1.6mm from the LED body. This defines the process window for hand or wave soldering.

2.2 Electrical & Optical Characteristics

These are the typical performance parameters measured at T_A=25°C and I_F=20mA, which is the standard test condition.

• Luminous Intensity (I_V): 140-240 mcd (millicandela). This specifies the perceived brightness of the LED as measured by a sensor filtered to match the human eye's photopic response (CIE curve). The wide range indicates a binning system is used (see Section 3).
• Viewing Angle (2θ_1/2): 75 degrees. This is the full angle at which the light intensity drops to half of its peak (on-axis) value. A 75° angle indicates a reasonably broad, diffused beam pattern suitable for wide-area indication.
• Peak Emission Wavelength (λ_P): 591 nm. This is the wavelength at which the spectral power output is highest.
• Dominant Wavelength (λ_d): 590 nm. This is a colorimetric measure derived from the CIE chromaticity diagram, representing the single wavelength that best describes the perceived color (amber) of the LED. It is the more relevant parameter for color specification.
• Spectral Line Half-Width (Δλ): 15 nm. This indicates the spectral purity or bandwidth of the emitted light. A narrower width would indicate a more monochromatic source.
• Forward Voltage (V_F): 2.4V (typical, max). The voltage drop across the LED when operating at 20mA. This is crucial for designing the current-limiting resistor in series.
• Reverse Current (I_R): 100 µA (max) at V_R=5V. A measure of the junction's leakage in the off-state.
• Capacitance (C): 40 pF (typical) at 0V bias and 1MHz. This is relevant for very high-speed switching applications, though typically negligible for indicator use.

3. Binning System Explanation

To ensure consistency in mass production, LEDs are sorted (binned) based on key optical parameters. This allows designers to select parts that meet specific brightness and color requirements.

3.1 Luminous Intensity Binning

Units: mcd @ 20mA. The provided bin code for this specific part number is 'GH', which corresponds to a minimum intensity of 140 mcd and a maximum of 240 mcd. Other available bins (JK, LM) offer higher intensity ranges (up to 680 mcd). The tolerance for each bin limit is ±15%.

3.2 Dominant Wavelength Binning

Units: nm @ 20mA. The datasheet lists bins from H14 (582-584 nm) to H20 (594-596 nm). The specific bin for the part number LTL1KHKSD is not listed in the provided excerpt, but it would fall within one of these ranges, defining its precise amber hue. The tolerance for each bin limit is ±1 nm, ensuring tight color control within a selected bin.

4. Performance Curve Analysis

While the specific graphs are not detailed in the text, typical curves for such an LED would include:

• I-V (Current-Voltage) Curve: Shows the exponential relationship between forward voltage and current. The knee voltage is around 2.0-2.1V for AlInGaP LEDs.
• Luminous Intensity vs. Forward Current (I_V vs. I_F): Generally a near-linear relationship, showing that brightness increases with current, but efficiency may drop at very high currents due to thermal effects.
• Luminous Intensity vs. Ambient Temperature: Shows the derating of light output as temperature increases. AlInGaP LEDs typically have good high-temperature performance compared to older technologies.
• Spectral Distribution: A plot of relative intensity vs. wavelength, showing a peak around 591 nm with a ~15 nm half-width, confirming the amber color.

5. Mechanical & Package Information

5.1 Package Dimensions

The LED features a 3.1 mm diameter round package. Key dimensional notes include: all dimensions are in mm; standard tolerance is ±0.25mm; maximum resin protrusion under the flange is 1.0mm; and lead spacing is measured at the exit point from the package body. The leads are designed for through-hole mounting.

5.2 Polarity Identification

For through-hole LEDs, the cathode is typically identified by a flat edge on the lens rim, a shorter lead, or a notch in the plastic flange. The specific marking should be verified on the component or its packaging.

6. Soldering & Assembly Guidelines

Proper handling is essential to prevent damage.

• Lead Forming: Must be done at room temperature, before soldering. Bend leads at a point at least 3mm from the base of the lens. Do not use the package body as a fulcrum.
• Soldering Clearance: Maintain a minimum of 2mm between the solder point and the base of the lens. Never immerse the lens in solder.
• Recommended Soldering Conditions:
  • Soldering Iron: 300°C max, 3 seconds max per lead.
  • Wave Soldering: Pre-heat to 100°C max for 60 sec max; solder wave at 260°C max for 10 sec max.
• Important: IR reflow soldering is NOT suitable for this through-hole type LED. Excessive heat or time can deform the lens or destroy the LED.
• Cleaning: Use only alcohol-based solvents like isopropyl alcohol if cleaning is necessary.

7. Packaging & Ordering Information

The standard packaging is as follows: LEDs are packed in bags of 1000, 500, or 250 pieces. Ten bags are placed in an inner carton (total 10,000 pcs). Eight inner cartons are packed into an outer shipping carton (total 80,000 pcs). Partial packs are only allowed in the final pack of a shipping lot.

8. Application Design Recommendations

8.1 Drive Circuit Design

LEDs are current-operated devices. To ensure uniform brightness and prevent over-current damage, a series current-limiting resistor is mandatory for each LED when powered from a voltage source. The resistor value (R) is calculated using Ohm's Law: R = (V_supply - V_F) / I_F. Using a common resistor for multiple LEDs in parallel (Circuit B in the datasheet) is not recommended due to variations in individual LED V_F, which can cause significant differences in brightness and current sharing.

8.2 Electrostatic Discharge (ESD) Protection

The LED is sensitive to ESD. Precautions must be taken during handling and assembly: use grounded wrist straps and work surfaces; employ ionizers to neutralize static on plastic lenses; and ensure all equipment is properly grounded.

8.3 Storage Conditions

For long-term storage outside the original sealed bag, store in a sealed container with desiccant or in a nitrogen ambient. The recommended storage environment is ≤30°C and ≤70% relative humidity. LEDs removed from their original packaging should ideally be used within three months.

9. Technical Comparison & Differentiation

This AlInGaP (Aluminum Indium Gallium Phosphide) LED represents an advancement over older technologies like GaAsP (Gallium Arsenide Phosphide). Key differentiators include:

• Higher Efficiency: AlInGaP provides more lumens per watt, leading to higher brightness for the same current or lower power consumption for the same brightness.
• Superior Temperature Stability: The luminous intensity of AlInGaP LEDs degrades less with increasing temperature compared to GaAsP.
• Better Color Saturation: The technology allows for brighter, more vivid amber and red colors.

10. Frequently Asked Questions (FAQs)

Q: Can I drive this LED directly from a 5V microcontroller pin?
A: No. The typical forward voltage is 2.4V, and a microcontroller pin cannot source 20mA reliably while also dropping ~2.6V. You must use a series resistor (e.g., (5V - 2.4V) / 0.02A = 130 Ohms) and likely a transistor switch driven by the MCU pin.

Q: Why is there a minimum luminous intensity (140 mcd) instead of just a typical value?
A: The binning system guarantees a minimum performance level. When you order from the 'GH' bin, you are assured every LED will meet or exceed 140 mcd under standard test conditions, ensuring consistency in your application.

Q: What is the difference between peak wavelength and dominant wavelength?
A> Peak wavelength is the physical peak of the emission spectrum. Dominant wavelength is a calculated value based on human color perception (CIE chart) and more accurately represents the color you actually see. For monochromatic LEDs like this amber one, they are often very close.

11. Practical Application Example

Scenario: Designing a mains-powered appliance power indicator.
The power supply provides a regulated 5V rail. The goal is to have a clearly visible, always-on amber indicator.

1. Current Selection: Choose I_F = 20mA (standard test current, ensures good brightness and longevity).
2. Resistor Calculation: Using the maximum V_F (2.4V) for a conservative design ensures brightness even with higher-V_F parts. R = (5V - 2.4V) / 0.02A = 130 Ohms. The nearest standard value is 130Ω or 120Ω.
3. Power Rating of Resistor: P = I²R = (0.02)² * 130 = 0.052W. A standard 1/8W (0.125W) or 1/4W resistor is more than sufficient.
4. PCB Layout: Place the LED near the panel cutout. Ensure the hole diameter accommodates the 3.1mm lens with clearance. Follow the 2mm minimum solder-to-body spacing rule in the footprint design.
5. Assembly: Insert LED, ensuring correct polarity. Use the recommended wave soldering profile, taking care not to overheat the component.

12. Operating Principle

An LED is a semiconductor diode. When a forward voltage exceeding its bandgap voltage is applied, electrons and holes recombine in the active region (the AlInGaP layer in this case). This recombination releases energy in the form of photons (light). The specific material composition (Al, In, Ga, P) determines the bandgap energy and thus the wavelength (color) of the emitted light. A diffused epoxy lens encapsulates the semiconductor die, providing mechanical protection, shaping the light output beam, and enhancing light extraction.

13. Technology Trends

The general trend in indicator LEDs is towards even higher efficiency and miniaturization. While through-hole packages like this 3.1mm lamp remain popular for their robustness and ease of manual assembly, surface-mount device (SMD) LEDs are dominating new designs due to their smaller size, suitability for automated pick-and-place assembly, and lower profile. However, through-hole LEDs maintain advantages in applications requiring high single-point brightness, superior heat dissipation via leads, or where mechanical strength for front-panel mounting is critical. The underlying AlInGaP material technology continues to be optimized for efficiency and reliability.