Takardar Bayani na Fasaha na SMD LED Mai Haske Raɗaɗi AlInGaP - Kallon Kusa na Digiri 120 - Ƙarfin Wutar Gaba 1.8-2.4V - Ragewar Wutar Lantarki 72mW - Takardar Bayani ta Fasaha Turanci

. Product Overview

This document details the specifications for a surface-mount device (SMD) light-emitting diode (LED) utilizing an Aluminum Indium Gallium Phosphide (AlInGaP) semiconductor material to produce a diffused yellow light output. Designed for automated printed circuit board (PCB) assembly, this component is characterized by its miniature footprint, making it suitable for space-constrained applications across a broad spectrum of electronic equipment.

.1 Core Advantages and Target Market

The primary advantages of this LED include its compliance with Restriction of Hazardous Substances (RoHS) directives, compatibility with automated pick-and-place equipment, and suitability for infrared (IR) reflow soldering processes. It is supplied in industry-standard 8mm tape on 7-inch diameter reels, facilitating high-volume manufacturing. The device is preconditioned to JEDEC Level 3 standards for moisture sensitivity. Its target applications span telecommunications infrastructure, office automation equipment, home appliances, industrial control panels, and indoor signage. Specific uses include status indicators, symbolic illumination, and front-panel backlighting.

. In-Depth Technical Parameter Analysis

A comprehensive understanding of the device's operational limits and performance under standard conditions is critical for reliable circuit design.

.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. All values are specified at an ambient temperature (Ta) of 25°C.

• Power Dissipation (Pd): mW. This is the maximum allowable power the device can dissipate as heat.
• Peak Forward Current (I_F(peak)): mA. This current is permissible only under pulsed conditions with a 1/10 duty cycle and a pulse width of 0.1ms.
• Continuous Forward Current (I_F): mA DC. This is the maximum recommended current for continuous operation.
• Operating Temperature Range:-40°C to +85°C.
• Storage Temperature Range:-40°C to +100°C.

.2 Electrical and Optical Characteristics

These parameters define the typical performance of the device under normal operating conditions, measured at Ta=25°C and a test current (I_F) of 20mA, unless otherwise stated.

• Luminous Intensity (I_V):Ranges from a minimum of 140.0 mcd to a maximum of 450.0 mcd. The typical value falls within this range. Intensity is measured using a sensor and filter combination that approximates the photopic (CIE) eye-response curve.
• Viewing Angle (2θ_/2): degrees (typical). This wide viewing angle, defined as the full angle at which luminous intensity drops to half its axial value, is a result of the diffused lens, providing a broad, even illumination pattern suitable for indicator applications.
• Peak Emission Wavelength (λ_P):Approximately 592 nm (typical). This is the wavelength at which the spectral power distribution reaches its maximum.
• Dominant Wavelength (λ_d):Specified between 584.5 nm and 594.5 nm. This is the single wavelength perceived by the human eye to define the color (yellow) and is derived from the CIE chromaticity coordinates.
• Spectral Line Half-Width (Δλ):Approximately 15 nm (typical). This indicates the spectral purity or bandwidth of the emitted light.
• Forward Voltage (V_F):Ranges from 1.8 V (min) to 2.4 V (max) at 20mA. The typical value lies within this range. This parameter is crucial for driver design and power supply selection.
• Reverse Current (I_R):Maximum of 10 μA when a reverse voltage (V_R) of 5V is applied. It is critical to note that the device is not designed for operation under reverse bias; this test condition is for characterization only.

. Binning System Explanation

To ensure consistency in production and allow designers to select LEDs with tightly grouped characteristics, the devices are sorted into bins based on key parameters.

.1 Forward Voltage (V_f) Binning

Units are in Volts (V) measured at I_F= 20mA. Each bin has a tolerance of ±0.1V.

• Bin D2:.8V (Min) to 2.0V (Max)
• Bin D3:.0V (Min) to 2.2V (Max)
• Bin D4:.2V (Min) to 2.4V (Max)

.2 Luminous Intensity (I_V) Binning

Units are in millicandelas (mcd) measured at I_F= 20mA. Tolerance on each bin is ±11%.

• Bin R2:.0 mcd to 180.0 mcd
• Bin S1:.0 mcd to 224.0 mcd
• Bin S2:.0 mcd to 280.0 mcd
• Bin T1:.0 mcd to 355.0 mcd
• Bin T2:.0 mcd to 450.0 mcd

.3 Dominant Wavelength (W_d) Binning

Units are in nanometers (nm) measured at I_F= 20mA. Tolerance for each bin is ±1nm.

• Bin H:.5 nm to 587.0 nm
• Bin J:.0 nm to 589.5 nm
• Bin K:.5 nm to 592.0 nm
• Bin L:.0 nm to 594.5 nm

. Performance Curve Analysis

The datasheet includes typical characteristic curves that illustrate the relationship between various parameters. These curves are essential for understanding device behavior under non-standard conditions.

.1 Current vs. Voltage (I-V) Characteristic

This curve shows the relationship between the forward voltage (V_F) and the forward current (I_F). For AlInGaP LEDs, this curve is typically exponential. Designers use this to determine the necessary driving voltage for a desired operating current and to calculate power dissipation (P_d= V_F* I_F).

.2 Luminous Intensity vs. Forward Current

This graph depicts how the light output (I_V) varies with the drive current (I_F). The relationship is generally linear within the recommended operating range but will saturate at higher currents. It is crucial for designing circuits where brightness control via current is required.

.3 Temperature Dependence

Curves showing the variation of forward voltage and luminous intensity with ambient temperature are typically included. Luminous intensity generally decreases as junction temperature increases, while forward voltage decreases. This information is vital for applications operating in extreme temperature environments.

. Mechanical and Package Information

.1 Package Dimensions and Polarity

The device conforms to an industry-standard SMD package outline. Detailed mechanical drawings specify the length, width, height, lead spacing, and overall tolerances (typically ±0.2mm). The package features a diffused lens to achieve the specified 120-degree viewing angle. Polarity is indicated by a cathode mark or a specific pad geometry on the device footprint.

.2 Recommended PCB Attachment Pad Layout

A land pattern design is provided to ensure reliable soldering and proper thermal management. This includes the recommended solder pad dimensions and spacing to prevent solder bridging and ensure a strong mechanical bond during reflow processes.

. Soldering and Assembly Guidelines

.1 IR Reflow Soldering Profile

A suggested temperature profile compliant with J-STD-020B for lead-free (Pb-free) soldering processes is provided. Key parameters include:

• Pre-heat Temperature:°C to 200°C.
• Pre-heat Time:Maximum 120 seconds.
• Peak Temperature:Maximum 260°C.
• Time Above Liquidus:Maximum 10 seconds (recommended not to exceed two reflow cycles).

It is emphasized that the optimal profile depends on the specific PCB design, solder paste, and oven, and should be characterized accordingly.

.2 Hand Soldering

If hand soldering is necessary, the following limits should be observed:

• Soldering Iron Temperature:Maximum 300°C.
• Soldering Time:Maximum 3 seconds per joint. This should be performed only once.

.3 Storage and Handling Conditions

Proper storage is critical to prevent moisture absorption, which can cause "popcorning" (package cracking) during reflow.

• Sealed Package:Store at ≤30°C and ≤70% Relative Humidity (RH). Use within one year.
• Opened Package:Store at ≤30°C and ≤60% RH. Components should be reflowed within 168 hours (7 days) of exposure. For longer storage, use a sealed container with desiccant or a nitrogen desiccator.
• Baking:If exposed for more than 168 hours, bake at approximately 60°C for at least 48 hours before assembly to remove moisture.

.4 Cleaning

If post-solder cleaning is required, use only specified solvents. Immersion in ethyl alcohol or isopropyl alcohol at room temperature for less than one minute is recommended. Unspecified chemicals may damage the LED package.

. Application Design Considerations

.1 Drive Method

LEDs are current-operated devices. To ensure uniform brightness when driving multiple LEDs, they should be connected in series with a current-limiting resistor or, preferably, driven by a constant current source. Connecting LEDs directly in parallel is not recommended due to variations in forward voltage (V_F), which can lead to significant current imbalance and uneven brightness.

.2 Thermal Management

While the power dissipation is relatively low (72mW max), proper thermal design on the PCB is still important, especially when operating at high ambient temperatures or near maximum current. Excessive junction temperature will reduce luminous output and shorten device lifetime. Ensuring adequate copper area around the solder pads aids in heat dissipation.

.3 Application Cautions

This product is intended for use in standard commercial and industrial electronic equipment. Special consultation is required for applications demanding exceptional reliability or where failure could jeopardize safety, such as in aviation, medical life-support, or transportation control systems. Designers must adhere to all absolute maximum ratings and recommended operating conditions.

. Packaging and Reel Specifications

The LEDs are supplied in an 8mm wide embossed carrier tape sealed with a cover tape, wound onto 7-inch (178mm) diameter reels. Each reel contains 2000 pieces. The packaging conforms to ANSI/EIA-481 specifications. Key dimensional details for the tape pocket and the reel hub/flange are provided to ensure compatibility with automated assembly equipment.

. Technical Comparison and Differentiation

The key differentiators of this AlInGaP yellow LED are its combination of a wide 120-degree viewing angle (enabled by the diffused lens) and the specific color properties of the AlInGaP material system, which typically offers high luminous efficiency and good color stability over temperature and current compared to some other yellow-emitting technologies. The detailed binning structure for V_F, I_V, and λ_dallows for precise selection in color- or brightness-critical applications.

. Frequently Asked Questions (Based on Technical Parameters)

.1 What is the difference between Peak Wavelength and Dominant Wavelength?

Peak Wavelength (λ_P) is the physical wavelength at which the LED emits the most optical power. Dominant Wavelength (λ_d) is a calculated value based on human color perception (CIE coordinates) and represents the single wavelength of the pure spectral color that matches the LED's perceived color. For design purposes, dominant wavelength is more relevant for color specification.

.2 Can I drive this LED at 30mA continuously?

Yes, 30mA DC is the maximum continuous forward current rating. However, for optimal longevity and reliability, it is often advisable to operate below the absolute maximum, for example, at the typical test current of 20mA. The actual drive current should be determined based on the required brightness and thermal conditions of the application.

.3 Why is there a strict time limit for reflow after opening the package?

SMD packages can absorb moisture from the atmosphere. During the high-temperature reflow soldering process, this trapped moisture can vaporize rapidly, creating internal pressure that may crack the package or delaminate internal interfaces—a failure known as "popcorning." The 168-hour floor life is the maximum recommended exposure time for which this risk is managed, assuming storage within the specified temperature and humidity limits.

. Design and Usage Case Study

Scenario: Designing a multi-indicator status panel for a network router.The panel requires several yellow status LEDs to be uniformly bright. The designer selects LEDs from the same Intensity bin (e.g., Bin T1: 280-355 mcd) to ensure minimal visual variation. To simplify the power supply design, LEDs from a tighter Forward Voltage bin (e.g., Bin D3: 2.0-2.2V) are chosen. The LEDs are driven in a series-string configuration from a 12V rail using a constant current driver set to 20mA, ensuring identical current through each LED and perfect brightness matching. The wide 120-degree viewing angle ensures the indicators are clearly visible from various angles in an office environment. The PCB layout includes the recommended pad geometry and a small thermal relief connection to a ground plane for heat dissipation.

. Operational Principle

This LED is based on an Aluminum Indium Gallium Phosphide (AlInGaP) semiconductor heterostructure. When a forward bias voltage exceeding the material's bandgap energy is applied, electrons and holes are injected into the active region where they recombine radiatively. The energy released during this recombination corresponds to photons in the yellow wavelength range (approximately 590 nm). The diffused epoxy lens encapsulating the semiconductor chip scatters the emitted light, broadening the radiation pattern from a narrow beam to the specified 120-degree viewing angle, creating a more diffuse and uniform appearance suitable for indicator applications.

. Technology Trends

Surface-mount LED technology continues to evolve towards higher efficiency, smaller package sizes, and improved color rendering. While AlInGaP remains a dominant material for high-efficiency red, orange, and yellow LEDs, ongoing research focuses on optimizing epitaxial structures and phosphor systems to push efficiency limits further. Trends in packaging include improved thermal management designs within the same footprint and the development of even thinner profiles for ultra-slim consumer electronics. The drive for automation and reliability continues to refine standards for tape-and-reel packaging and reflow soldering compatibility.