3.1mm Diffused Red LED Lamp Datasheet - 3.1mm Diameter - 2.4V Forward Voltage - 75mW Power Dissipation - English Technical Document

1. Product Overview

This document provides the complete technical specifications for a through-hole mounted, diffused lens LED lamp. The device is designed for general-purpose indicator and illumination applications where reliable performance and ease of assembly are required. The primary component material is AlInGaP (Aluminum Indium Gallium Phosphide), which is known for its high efficiency and stability in producing red light. The product is compliant with RoHS directives, indicating it is free from hazardous substances like lead (Pb).

The core advantages of this LED include its high luminous intensity output, which ensures good visibility even in moderately lit environments. It features low power consumption, making it suitable for battery-powered devices or applications where energy efficiency is a priority. The device is compatible with integrated circuits due to its low current requirement, allowing for direct drive from microcontroller GPIO pins or logic outputs with appropriate current-limiting resistors. The 3.1mm diameter package offers a versatile form factor for mounting on printed circuit boards (PCBs) or panels.

2. Technical Parameter Deep Dive

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. The maximum continuous power dissipation is 75 mW. The peak forward current, permissible under pulsed conditions (1/10 duty cycle, 0.1ms pulse width), is 90 mA. The maximum recommended continuous DC forward current is 30 mA. A derating factor of 0.4 mA/°C applies linearly from 50°C upwards, meaning the safe operating current decreases as temperature increases. The device can operate within an ambient temperature range of -40°C to +100°C and can be stored in temperatures from -55°C to +100°C. For soldering, the leads can withstand 260°C for a maximum of 5 seconds when measured 2.0 mm from the LED body.

2.2 Electrical and Optical Characteristics

The typical operating characteristics are measured at T_A=25°C and a forward current (I_F) of 20 mA, which is the standard test condition.

• Luminous Intensity (I_V): Ranges from a minimum of 85 mcd to a maximum of 310 mcd, with a typical value of 240 mcd. This measurement uses a sensor and filter approximating the CIE photopic eye-response curve.
• Viewing Angle (2θ_1/2): 60 degrees. This is the full angle at which the luminous intensity drops to half of its axial (on-axis) value, characteristic of a diffused lens which spreads light.
• Peak Emission Wavelength (λ_P): 632 nm. This is the wavelength at which the spectral power distribution is highest.
• Dominant Wavelength (λ_d): Ranges from 617 nm to 629 nm, with a typical value of 621 nm. This is the single wavelength perceived by the human eye that defines the color (red) of the LED, derived from the CIE chromaticity diagram.
• Spectral Line Half-Width (Δλ): 20 nm. This indicates the spectral purity; a smaller value would indicate a more monochromatic light source.
• Forward Voltage (V_F): Typically 2.4 V, with a maximum of 2.4 V at I_F=20mA. The minimum is 2.0 V.
• Reverse Current (I_R): Maximum of 100 μA when a reverse voltage (V_R) of 5V is applied. It is critical to note that the device is not designed for reverse operation; this test condition is for characterization only.

3. Binning System Explanation

The product is sorted into bins based on key performance parameters to ensure consistency within a production batch or for specific application needs.

3.1 Luminous Intensity Binning

LEDs are classified into three intensity bins, measured in millicandelas (mcd) at 20mA:

• Bin EF: Minimum 85 mcd, Maximum 140 mcd.
• Bin GH: Minimum 140 mcd, Maximum 240 mcd.
• Bin J: Minimum 240 mcd, Maximum 310 mcd.

The tolerance for each bin limit is ±15%.

3.2 Dominant Wavelength Binning

LEDs are also binned by their dominant wavelength to control color consistency:

• Bin H28: 617.0 nm to 621.0 nm.
• Bin H29: 621.0 nm to 625.0 nm.
• Bin H30: 625.0 nm to 629.0 nm.

The tolerance for each bin limit is ±1 nm. The specific bin codes for intensity and wavelength would typically be marked on packaging or available from the supplier to allow precise selection for color- or brightness-critical applications.

4. Performance Curve Analysis

While the PDF references typical characteristic curves, the provided text does not include the actual graphs. Based on standard LED behavior and the parameters given, one can infer the nature of these curves. The I-V (Current-Voltage) curve would show an exponential relationship, with the forward voltage being approximately 2.0-2.4V at the test current of 20mA. The Luminous Intensity vs. Forward Current (I_V-I_F) curve is generally linear in the normal operating range, indicating that light output is directly proportional to current. The Luminous Intensity vs. Ambient Temperature curve would show a negative coefficient, meaning light output decreases as junction temperature increases. The Spectral Distribution curve would be a bell-shaped curve centered around the peak wavelength of 632 nm with a half-width of 20 nm, defining the red color output.

5. Mechanical and Packaging Information

5.1 Package Dimensions

The device is housed in a 3.1mm diameter round package with a diffused lens. Key dimensional notes include: all dimensions are in millimeters (inches); standard tolerance is ±0.25mm unless specified otherwise; the maximum protrusion of resin under the flange is 1.0mm; and lead spacing is measured where the leads emerge from the package body. A detailed dimensioned drawing would typically show the body diameter, lens shape, lead length, and lead diameter.

5.2 Polarity Identification

For through-hole LEDs, polarity is usually indicated by lead length (the longer lead is the anode, positive) or by a flat spot on the lens rim or the plastic flange. The cathode (negative) is typically associated with the shorter lead or the side with the flat spot.

5.3 Packing Specification

The LEDs are packaged in anti-static bags. Standard packing quantities are 1000, 500, 200, or 100 pieces per bag. Ten of these bags are placed into an inner carton, totaling 10,000 pieces. Finally, eight inner cartons are packed into an outer shipping carton, resulting in a total of 80,000 pieces per outer carton. It is noted that in every shipping lot, only the final pack may not be a full pack.

6. Soldering and Assembly Guidelines

6.1 Storage Conditions

LEDs should be stored in an environment not exceeding 30°C and 70% relative humidity. If removed from their original moisture-barrier packaging, it is recommended to use them within three months. For longer-term storage outside the original bag, they should be kept in a sealed container with desiccant or in a nitrogen ambient desiccator to prevent moisture absorption.

6.2 Lead Forming

If leads need to be bent, this must be done at normal room temperature and before soldering. The bend should be made at a point at least 3mm away from the base of the LED lens. The base of the lead frame should not be used as a fulcrum during bending to avoid stress on the epoxy seal. During PCB assembly, minimal clinching force should be used.

6.3 Soldering Process

For this through-hole lamp type, wave soldering or hand soldering with an iron are suitable processes. Infrared (IR) reflow is not recommended. A minimum clearance of 3mm must be maintained from the base of the lens to the solder point to prevent epoxy from climbing up the leads and to avoid thermal damage. The LED lens must not be dipped into solder.

Recommended Soldering Conditions:

• Soldering Iron: Maximum temperature 350°C, maximum soldering time 3 seconds per lead (one time only).
• Wave Soldering: Maximum pre-heat temperature 100°C for up to 60 seconds. Maximum solder wave temperature 260°C, with a maximum contact time of 5 seconds.

Excessive temperature or time can cause lens deformation or catastrophic failure.

7. Application Recommendations

7.1 Intended Use and Cautions

This LED is designed for ordinary electronic equipment including office equipment, communication devices, and household applications. It is not recommended for use in safety-critical or high-reliability applications where failure could jeopardize life or health (e.g., aviation, medical life-support, transportation control) without prior consultation and qualification.

7.2 Drive Circuit Design

LEDs are current-operated devices. To ensure uniform brightness when driving multiple LEDs in parallel, it is strongly recommended to use a individual current-limiting resistor in series with each LED (Circuit Model A). Driving LEDs in parallel directly from a voltage source (Circuit Model B) is discouraged because small variations in the forward voltage (V_F) characteristic between individual LEDs can cause significant differences in current sharing and, consequently, uneven brightness. The series resistor value can be calculated using Ohm's Law: R = (V_supply - V_F) / I_F, where I_F is the desired forward current (e.g., 20mA).

7.3 Electrostatic Discharge (ESD) Protection

These LEDs are susceptible to damage from electrostatic discharge. Precautions must be taken during handling and assembly:

• Operators should wear grounded wrist straps or anti-static gloves.
• All equipment, workstations, and storage racks must be properly grounded.
• Use an ionizer to neutralize static charge that may build up on the plastic lens surface.

ESD damage can manifest as high reverse leakage current, abnormally low forward voltage, or failure to illuminate at low currents.

8. Cleaning

If cleaning is necessary after soldering, only alcohol-based solvents such as isopropyl alcohol should be used. Harsh chemicals or ultrasonic cleaning may damage the epoxy lens or the internal structure.

9. Technical Comparison and Considerations

Compared to older technologies like GaAsP (Gallium Arsenide Phosphide) red LEDs, this AlInGaP device offers significantly higher luminous efficiency, resulting in greater brightness for the same input current. The diffused lens provides a wider, more uniform viewing angle compared to a clear or water-clear lens, which is ideal for status indicators that need to be seen from various angles. The 3.1mm size is a common industry standard, offering a good balance between light output and board space consumption, compared to smaller 2mm or 3mm LEDs, or larger 5mm and 10mm types.

10. Frequently Asked Questions (FAQ)

Q: What is the difference between Peak Wavelength and Dominant Wavelength?
A: Peak Wavelength (λ_P=632nm) is the physical peak of the light spectrum the LED emits. Dominant Wavelength (λ_d=~621nm) is a calculated value based on human color perception (CIE chart) that defines the visual color. They are often different.

Q: Can I drive this LED without a series resistor?
A: No. Connecting an LED directly to a voltage source is likely to cause excessive current flow, overheating, and immediate failure. A series resistor is mandatory for current regulation.

Q: Why is there a binning system?
A: Manufacturing variations cause slight differences in performance. Binning sorts LEDs into groups with tightly controlled parameters (brightness, color), allowing designers to select the appropriate bin for applications requiring consistency.

Q: What happens if I exceed the Absolute Maximum Ratings?
A: Operating beyond these limits, even briefly, can cause irreversible damage, such as reduced light output, color shift, or complete failure. Always design with a safety margin.

11. Design and Usage Case Study

Scenario: Designing a multi-indicator panel for a consumer audio amplifier. The panel requires 10 red power/status indicators. To ensure all LEDs have identical brightness and color, the designer specifies LEDs from the same intensity bin (e.g., GH bin: 140-240 mcd) and the same wavelength bin (e.g., H29: 621-625 nm) from the supplier. A 5V rail is available on the board. Using the typical V_F of 2.4V and a target I_F of 20mA, the series resistor is calculated: R = (5V - 2.4V) / 0.020A = 130 Ohms. A standard 130Ω or 150Ω resistor is chosen. Each LED gets its own resistor connected to the 5V rail, controlled by a transistor or GPIO pin from the amplifier's microcontroller. During assembly, technicians use ESD-safe practices and hand-solder the LEDs at 320°C for less than 2 seconds per lead, ensuring the 3mm clearance from the lens is maintained.

12. Operating Principle

An LED is a semiconductor diode. When a forward voltage exceeding its bandgap 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 (AlInGaP) determines the bandgap energy, which directly defines the wavelength (color) of the emitted light—in this instance, in the red spectrum. The diffused epoxy lens contains scattering particles that randomize the direction of the emitted photons, creating a wider, softer beam pattern compared to a clear lens.

13. Technology Trends

The general trend in LED technology is toward higher efficiency (more lumens per watt), improved color rendering, and greater reliability. For indicator-type LEDs, miniaturization continues (e.g., 1.6mm, 1.0mm packages). There is also a growing emphasis on broader and more consistent viewing angles and tighter binning tolerances to meet the demands of consumer electronics and automotive applications. Furthermore, the drive for sustainability pushes for materials and processes with lower environmental impact throughout the lifecycle.