T-1-3-4-Amber-Yellow-LED-Datasheet - Through-Hole-Lamp - Voltage-2.4V - Power-75mW - English-Technical-Document

1. Product Overview

This document provides the complete technical specifications for a high-performance, through-hole mounted LED lamp. The device is designed for applications requiring reliable, visible indicator lighting with excellent luminous output and energy efficiency. Its primary function is to serve as a status indicator, backlight, or general-purpose illumination source in various electronic equipment.

The core advantages of this component include its high luminous intensity output, which ensures excellent visibility even in well-lit environments. It features low power consumption, making it suitable for battery-powered or energy-sensitive applications. The device is highly efficient, converting electrical energy into light with minimal waste heat. Its versatile mounting capability allows for easy installation on printed circuit boards (PCBs) or panels. Furthermore, it is IC-compatible, requiring only low drive currents, which simplifies circuit design. The component utilizes the popular T-1 3/4 package diameter, ensuring broad compatibility with standard PCB layouts and manufacturing processes.

The target market for this LED includes consumer electronics, industrial control panels, automotive interior lighting, instrumentation, and any application where a durable, bright, and efficient indicator light is required.

2. In-Depth Technical Parameter Analysis

2.1 Absolute Maximum Ratings

The absolute maximum ratings define the stress limits beyond which permanent damage to the device may occur. These ratings are specified at an ambient temperature (T_A) of 25°C and must not be exceeded under any operating conditions.

• Power Dissipation (P_D): 75 mW. This is the maximum amount of power the device can dissipate as heat. Exceeding this limit risks thermal runaway and failure.
• Peak Forward Current (I_FP): 60 mA. This is the maximum allowable current under pulsed conditions, defined with a 1/10 duty cycle and a 0.1ms pulse width. It is significantly higher than the continuous current rating, allowing for brief periods of high-brightness signaling.
• Continuous Forward Current (I_F): 30 mA. This is the maximum DC current that can be applied continuously without degrading the LED's performance or lifespan.
• Derating Factor: Linear from 50°C at 0.4 mA/°C. For ambient temperatures above 50°C, the maximum allowable continuous forward current must be reduced. For example, at 70°C, the maximum I_F would be 30 mA - [0.4 mA/°C * (70°C - 50°C)] = 22 mA.
• Reverse Voltage (V_R): 5 V. Applying a reverse voltage greater than this value can cause immediate and catastrophic failure of the LED junction.
• Operating Temperature Range: -40°C to +100°C. The device is guaranteed to function within this ambient temperature range.
• Storage Temperature Range: -55°C to +100°C. The device can be stored without degradation within these limits.
• Lead Soldering Temperature: 260°C for 5 seconds, measured 1.6mm (0.063") from the LED body. This defines the acceptable thermal profile for hand or wave soldering processes.

2.2 Electrical and Optical Characteristics

The electrical and optical characteristics are measured at T_A=25°C and define the typical performance of the device under normal operating conditions. These are the key parameters for circuit design and performance expectation.

• Luminous Intensity (I_V): Minimum 180 mcd, Typical 700 mcd at I_F = 20 mA. This is a measure of the perceived brightness of the LED as seen by the human eye, measured using a sensor filtered to match the CIE photopic response curve. The wide range indicates a binning process; the specific intensity for a given unit is marked on its packaging.
• Viewing Angle (2θ_1/2): 30 degrees. This is the full angle at which the luminous intensity drops to half of its value measured on-axis. A 30-degree angle indicates a relatively focused beam, suitable for directed indicator applications.
• Peak Emission Wavelength (λ_P): 595 nm. This is the wavelength at which the spectral power output of the LED is maximum. It falls within the amber-yellow region of the visible spectrum.
• Dominant Wavelength (λ_d): 592 nm. Derived from the CIE chromaticity diagram, this is the single wavelength that best represents the perceived color of the LED light. It is very close to the peak wavelength, confirming a pure amber-yellow color.
• Spectral Line Half-Width (Δλ): 15 nm. This parameter indicates the spectral purity or bandwidth of the emitted light. A value of 15 nm is typical for AlInGaP-based LEDs and results in a saturated color.
• Forward Voltage (V_F): Typical 2.4 V, Maximum 2.4 V at I_F = 20 mA. This is the voltage drop across the LED when operating. It is crucial for designing the current-limiting resistor in series with the LED. The datasheet shows a minimum of 2.05V, but the typical/max is given as 2.4V, suggesting a tight distribution around this value.
• Reverse Current (I_R): Maximum 100 µA at V_R = 5 V. This is the small leakage current that flows when the LED is reverse-biased within its maximum rating.
• Capacitance (C): 40 pF at V_F = 0V, f = 1 MHz. This is the junction capacitance, which can be relevant in high-frequency switching applications.

3. Binning System Explanation

The datasheet implies the use of a binning system, primarily for luminous intensity. Note 3 states: "I_v classification code is marked on each packing bag." This indicates that manufactured LEDs are tested and sorted (binned) based on their measured luminous intensity. The specification lists a range from 180 mcd (minimum) to 700 mcd (typical). Units are grouped into specific intensity bins (e.g., 180-250 mcd, 250-350 mcd, etc.), and the bin code is printed on the packaging. This allows designers to select LEDs with consistent brightness for their application. While not explicitly detailed for wavelength or forward voltage in this document, such parameters are also commonly binned in LED manufacturing to ensure color and electrical consistency.

4. Performance Curve Analysis

The final page of the datasheet is dedicated to "Typical Electrical / Optical Characteristics Curves." While the specific curves are not provided in the text content, standard LED datasheets typically include the following graphs, which are critical for understanding device behavior under varying conditions:

• Relative Luminous Intensity vs. Forward Current (I-V Curve): This curve shows how light output increases with drive current. It is typically linear at lower currents but may saturate at higher currents due to thermal effects and efficiency droop.
• Forward Voltage vs. Forward Current: This shows the exponential relationship, confirming the diode behavior. It is used to calculate power dissipation (V_F * I_F).
• Relative Luminous Intensity vs. Ambient Temperature: This curve demonstrates the thermal derating of light output. For most LEDs, luminous intensity decreases as junction temperature increases.
• Peak Wavelength vs. Ambient Temperature: This shows how the emitted color shifts (usually to longer wavelengths) as temperature increases.
• Spectral Distribution: A plot of relative intensity versus wavelength, showing the peak at 595 nm and the ~15 nm half-width, defining the amber-yellow color.

These curves allow designers to predict performance in real-world conditions where temperature and drive current may vary.

5. Mechanical and Package Information

5.1 Package Dimensions

The LED uses a standard "T-1 3/4" radial through-hole package. Key dimensional notes from the datasheet include:

• All dimensions are in millimeters, with inches in parentheses.
• A standard tolerance of ±0.25mm (±0.010") applies unless specified otherwise.
• The resin under the flange may protrude by a maximum of 1.0mm (0.04").
• Lead spacing is measured at the point where the leads emerge from the package body, which is critical for PCB hole spacing.

The specific dimensional drawing would show the body diameter (T-1 3/4 is approximately 5mm), lead length, lead diameter, and the position of the flange. The longer lead typically denotes the anode (positive side).

5.2 Polarity Identification

For through-hole LEDs, polarity is most commonly indicated by lead length (the longer lead is the anode) and sometimes by a flat spot on the LED lens or body near the cathode lead. The datasheet should be consulted for the specific marking, but the lead length method is almost universally applied.

6. Soldering and Assembly Guidelines

The key soldering parameter provided is the maximum allowable temperature for the leads: 260°C for 5 seconds, measured 1.6mm from the body. This is critical to prevent thermal damage to the internal wire bonds and the epoxy lens.

Recommended Practices:

• Hand Soldering: Use a temperature-controlled iron. Apply heat to the lead and PCB pad, not the LED body. Complete the solder joint within 3-5 seconds.
• Wave Soldering: Ensure the preheat and solder wave profiles do not expose the LED leads to temperatures exceeding 260°C for more than the specified time. The LED body should be above the solder wave.
• Cleaning: If cleaning is necessary, use solvents compatible with epoxy resin. Avoid ultrasonic cleaning, as it may damage the LED structure.
• Bending Leads: If lead forming is required, bend the leads at least 3mm from the body to avoid stress on the seal. Use proper tools to avoid nicking the leads.

Storage Conditions: Store in a dry, anti-static environment within the specified temperature range of -55°C to +100°C. Avoid exposure to high humidity or corrosive gases.

7. Packaging and Ordering Information

The part number for this device is LTL2R3KYK. A typical LED naming convention might break down as follows: "LTL" could indicate a through-hole lamp, "2" might relate to a series or color, "R3" could specify intensity bin or viewing angle, and "KYK" likely denotes the lens/color (Water Clear lens, Amber Yellow color from an AlInGaP source).

Packaging is typically in anti-static bags or tape-and-reel (for automated assembly), with the luminous intensity bin code marked on each bag as per Note 3. Standard quantities are often 1000 pieces per bag or reel.

8. Application Recommendations

8.1 Typical Application Circuits

The most common application is as a status indicator powered by a DC voltage source (e.g., 3.3V, 5V, 12V). A current-limiting resistor is mandatory. The resistor value (R_S) is calculated using Ohm's Law: R_S = (V_CC - V_F) / I_F.

Example for 5V supply, targeting I_F = 20mA:

V_F (typical) = 2.4V

R_S = (5V - 2.4V) / 0.020A = 130 Ω.

The nearest standard value (120Ω or 150Ω) can be used. The power rating of the resistor should be at least P = I_F² * R_S = (0.02)² * 130 = 0.052W, so a 1/8W (0.125W) resistor is sufficient.

For microcontroller GPIO pin driving, ensure the pin can source or sink the required 20mA. Many modern MCUs have lower per-pin limits (e.g., 8-10mA), so a transistor buffer might be necessary.

8.2 Design Considerations

• Thermal Management: Although power dissipation is low (max 75mW), ensure adequate spacing between LEDs and other heat sources on the PCB. Adhere to the current derating curve above 50°C ambient.
• Current Control: Always use a series resistor or constant current driver. Driving an LED directly from a voltage source will result in excessive current and rapid failure.
• Reverse Voltage Protection: If there is any possibility of a reverse voltage being applied (e.g., in AC circuits or during board testing), include a protection diode in parallel with the LED (cathode to anode) to clamp the reverse voltage to about 0.7V.
• Viewing Angle: The 30-degree viewing angle provides a directed beam. For wider area illumination, consider using a diffuser lens or selecting an LED with a wider viewing angle.

9. Technical Comparison and Differentiation

This AlInGaP-based amber-yellow LED offers distinct advantages compared to older technologies like filtered incandescent bulbs or standard GaAsP LEDs.

• vs. Incandescent Lamps: Far lower power consumption (mW vs. Watts), much longer lifespan (tens of thousands of hours vs. hundreds), higher shock and vibration resistance, and faster switching speed. The color is inherent to the semiconductor material, not a filter, so it does not fade.
• vs. Standard GaAsP Yellow LEDs: AlInGaP technology provides significantly higher luminous efficiency and brightness (mcd/mA). It also offers better temperature stability and color consistency over time and operating conditions.
• vs. SMD LEDs: The through-hole design offers superior mechanical strength for applications subject to vibration or where the LED may be physically touched or manipulated. It is also easier for prototyping and manual assembly.

10. Frequently Asked Questions (FAQs)

Q1: What resistor do I need for a 12V circuit?

A1: Using V_F = 2.4V and I_F = 20mA: R = (12 - 2.4) / 0.02 = 480 Ω. Use a standard 470 Ω resistor. Power dissipation: P = (0.02)^2 * 470 = 0.188W, so a 1/4W resistor is recommended.

Q2: Can I drive this LED with a PWM signal for dimming?

A2: Yes, LEDs are ideal for PWM dimming. Ensure the PWM frequency is high enough (typically >100Hz) to avoid visible flicker. The peak current in each pulse should not exceed the absolute maximum peak forward current of 60mA.

Q3: Why is my LED dimmer than expected?

A3: First, verify the forward current is actually 20mA by measuring the voltage drop across the series resistor. Second, check the ambient temperature; light output decreases with temperature. Third, confirm the LED's intensity bin from the packaging; you may have a unit from the lower end of the bin range.

Q4: Is a heatsink required?

A4: For continuous operation at 20mA and room temperature, a heatsink is generally not required due to the low power dissipation (approx. 48mW). However, if operating at the maximum continuous current (30mA) or in a high ambient temperature environment (>50°C), ensuring good PCB copper area around the leads can help with heat dissipation.

11. Practical Design and Usage Case

Case: Industrial Control Panel Status Indicator

An industrial machine uses a central control panel with multiple status LEDs. A green LED indicates "Power On," a red LED indicates "Fault," and this amber-yellow LED is used to indicate "Standby" or "Warning."

Implementation: The LED is mounted on the front panel. It is driven by a 24V DC supply rail common in industrial settings. A transistor switch, controlled by the machine's PLC output, turns the LED on/off. The series resistor is calculated for 20mA: R = (24V - 2.4V) / 0.02A = 1080 Ω (use 1.1kΩ). The resistor power rating needs to be P = (24-2.4)*0.02 = 0.432W, so a 0.5W resistor is selected. The 30-degree viewing angle ensures the warning light is clearly visible to the operator directly in front of the panel, without causing excessive glare from wide angles. The high luminous intensity (up to 700 mcd) guarantees visibility even in brightly lit factory environments.

12. Operating Principle Introduction

This LED is based on Aluminum Indium Gallium Phosphide (AlInGaP) semiconductor material. When a forward voltage exceeding the diode's junction potential (approximately 2.0-2.4V for AlInGaP) is applied, electrons from the n-type region and holes from the p-type region are injected into the active region. When these charge carriers (electrons and holes) recombine, they release energy in the form of photons (light). The specific wavelength of the emitted light (amber-yellow, 592-595 nm) is determined by the bandgap energy of the AlInGaP alloy composition used in the active layer. The "Water Clear" lens is made of epoxy resin that is transparent to the emitted wavelength, allowing the light to escape efficiently while also providing mechanical protection and shaping the beam pattern (30-degree viewing angle).

13. Technology Trends and Developments

While through-hole LEDs remain vital for specific applications requiring robustness and ease of manual assembly, the overall industry trend has shifted significantly towards Surface-Mount Device (SMD) packages. SMD LEDs offer advantages in automated assembly, smaller footprint, lower profile, and often better thermal management to the PCB. For AlInGaP technology itself, ongoing development focuses on increasing luminous efficacy (lumens per watt), improving high-temperature performance, and achieving even tighter color and intensity binning for applications requiring precise color matching, such as full-color displays and automotive lighting. Furthermore, the development of phosphor-converted LEDs that use a blue or violet chip to excite a phosphor to produce amber/yellow light offers alternative pathways to achieve specific color points with potentially higher efficiency or color rendering properties.