Yellow SMD LED 0402 Specification - Size 1.0x0.5x0.4mm - Voltage 1.7-2.4V - Power 48mW - Technical Datasheet in English

1. Product Overview

This document details the specifications for a compact, high-performance yellow Light Emitting Diode (LED) designed for surface-mount technology (SMT) applications. The device is fabricated using a yellow semiconductor chip and is housed in a miniature 0402 package footprint, making it suitable for space-constrained modern electronics.

1.1 General Description

The LED is a monochromatic light source emitting in the yellow wavelength region. Its primary construction involves a yellow chip encapsulated within a resin package. The ultra-small form factor (1.0mm x 0.5mm x 0.4mm) is a key enabler for high-density PCB designs commonly found in consumer electronics, automotive interiors, and industrial control panels.

1.2 Core Features and Advantages

• Extremely Wide Viewing Angle: The device offers a typical viewing angle (2θ1/2) of 140 degrees, ensuring uniform luminous intensity and visibility from a broad range of perspectives. This is crucial for status indicators and panel lighting.
• SMT Compatibility: The package is fully compatible with standard automated pick-and-place machines and all mainstream SMT assembly and solder reflow processes, facilitating high-volume manufacturing.
• Environmental Compliance: The product is compliant with RoHS (Restriction of Hazardous Substances) directives. It is classified with a Moisture Sensitivity Level (MSL) of Level 3, which defines specific handling and baking requirements prior to reflow to prevent popcorning or delamination.
• Robust ESD Protection: With an Electrostatic Discharge (ESD) withstand capability of 2000V (Human Body Model), the LED offers good handling robustness for typical assembly environments.

1.3 Target Applications and Market

This LED is designed as a versatile indicator and backlight component. Its primary target markets include:

• Optical Indicators: Power status, connectivity alerts, and functional mode indicators in devices such as routers, chargers, and smart home appliances.
• Switch and Symbol Illumination: Backlighting for membrane switches, keypads, and instrument panel symbols.
• General Purpose Lighting: Decorative lighting, accent lighting, and other applications where a compact yellow light source is required.

2. In-Depth Technical Parameter Analysis

The performance of the LED is characterized under specific test conditions, typically at an ambient temperature (Ts) of 25°C and a forward current (IF) of 5mA. Understanding these parameters is critical for proper circuit design and performance prediction.

2.1 Electrical and Optical Characteristics

The key performance metrics are summarized in the datasheet tables. A detailed interpretation is provided below:

• Dominant Wavelength (λD): This defines the perceived color of the LED. The device is offered in yellow bins with dominant wavelengths ranging from 585nm to 595nm. The human eye perceives light in this range as a pure yellow hue.
• Luminous Intensity (IV): Measured in millicandelas (mcd), this quantifies the perceived brightness. The product is available in multiple intensity bins, from A00 (8-12 mcd) to F00 (65-100 mcd) at 5mA. Designers must select the appropriate bin based on application brightness requirements and drive current.
• Forward Voltage (VF): The voltage drop across the LED when conducting current. It is a crucial parameter for power supply design. The VF is binned from A2 (1.7-1.8V) to D2 (2.3-2.4V) at 5mA. Higher VF bins may require a slightly higher supply voltage to achieve the same current, affecting overall system efficiency.
• Spectral Half Bandwidth (∆λ): This parameter, typically around 15nm, indicates the spectral purity of the emitted light. A smaller bandwidth means a more saturated, pure color.
• Viewing Angle (2θ1/2): The full angle at which the luminous intensity is half of the peak intensity. The specified 140° is exceptionally wide, characteristic of a lambertian or near-lambertian emission pattern.
• Reverse Current (IR): The leakage current when a reverse bias of 5V is applied. The maximum is 10µA, which is standard for such devices.
• Thermal Resistance (RθJ-S): This parameter, specified as 450°C/W, defines the temperature rise from the semiconductor junction to the solder point (or case) per watt of power dissipated. It is vital for thermal management calculations to ensure the junction temperature (Tj) does not exceed its maximum rating.

2.2 Absolute Maximum Ratings

These ratings define the stress limits beyond which permanent damage may occur. Operation under or at these limits is not guaranteed.

• Power Dissipation (Pd): Maximum allowable power dissipation is 48mW. Exceeding this limit risks thermal runaway and device failure.
• Forward Current (IF): The maximum continuous forward current is 20mA.
• Peak Forward Current (IFP): A higher pulsed current of 60mA is allowed under specific conditions (1/10 duty cycle, 0.1ms pulse width), useful for multiplexing or short-burst brightness enhancement.
• Temperature Ranges: Operating temperature (Topr) and storage temperature (Tstg) are both specified from -40°C to +85°C, making the device suitable for industrial and automotive applications.
• Maximum Junction Temperature (Tj): The absolute maximum temperature allowed at the semiconductor junction is 95°C. The designer must ensure that the combined effects of ambient temperature and self-heating do not exceed this value.

3. Binning System Explanation

To ensure consistent color and brightness in production, LEDs are sorted into bins based on key parameters. This device employs a multi-dimensional binning system.

3.1 Forward Voltage (VF) Binning

The LED is categorized into seven voltage bins (A2, B1, B2, C1, C2, D1, D2). This allows designers to select parts with tighter voltage tolerances for applications where consistent current draw or voltage matching across multiple LEDs in series is critical.

3.2 Dominant Wavelength (λD) Binning

The yellow emission is sorted into four wavelength bins (D10, D20, E10, E20). This ensures color uniformity within a single product batch. For applications demanding precise color consistency, specifying a single wavelength bin is essential.

3.3 Luminous Intensity (IV) Binning

Six intensity bins (A00 to F00) are defined. This provides flexibility: designers can choose lower-brightness bins for subtle indicators or higher-brightness bins for applications requiring high visibility. The binning tolerance (±10%) must be factored into brightness calculations.

4. Performance Curve Analysis

The provided graphs offer deeper insight into the device's behavior under varying conditions.

4.1 Forward Voltage vs. Forward Current (IV Curve)

The graph shows a non-linear relationship. The forward voltage increases with current but not linearly, typical of a diode's exponential I-V characteristic. This curve is essential for designing the current-limiting circuit, often a simple resistor, to ensure stable operation across supply voltage variations.

4.2 Forward Current vs. Relative Luminous Intensity

This curve demonstrates that light output increases with drive current, but not necessarily in a perfectly linear fashion, especially at higher currents. It helps designers choose an operating current that balances brightness with efficiency and device longevity.

4.3 Temperature Dependence

Two key graphs illustrate thermal effects: Pin Temperature vs. Relative Intensity: Shows that light output typically decreases as the ambient (or pin) temperature rises. This thermal quenching effect must be considered in high-temperature environments. Pin Temperature vs. Forward Current: Indicates how the forward voltage (implied by the current at a fixed voltage) changes with temperature. LEDs have a negative temperature coefficient for forward voltage, which can be used for temperature sensing in some applications.

4.4 Spectral Characteristics

Forward Current vs. Dominant Wavelength: Shows minimal shift in peak wavelength with changing drive current, indicating good color stability. Relative Intensity vs. Wavelength: The spectral distribution curve confirms the emission is centered in the yellow region (around 590nm) with the specified half bandwidth, showing a single, well-defined peak without significant sidebands.

5. Mechanical and Package Information

5.1 Package Dimensions and Tolerances

The physical outline is defined by top, bottom, and side views. Key dimensions include an overall length of 1.0mm, width of 0.5mm, and height of 0.4mm. Unless otherwise specified, dimensional tolerances are ±0.2mm. The land pattern (soldering footprint) recommendation is provided, featuring two pads with dimensions of 0.6mm x 0.5mm and a gap of 0.22mm between them. Adhering to this pattern is critical for proper solder joint formation and self-alignment during reflow.

5.2 Polarity Identification

The cathode (negative terminal) is clearly marked. Proper polarity identification is essential during assembly to prevent reverse biasing, which can damage the device.

6. Soldering and Assembly Guidelines

6.1 SMT Reflow Soldering Process

The LED is designed for standard infrared or convection reflow soldering processes. While specific peak temperature and time-above-liquidus (TAL) profiles are not detailed in the provided excerpt, general best practices for MSL Level 3 components apply. These include: - Using the component within its specified floor life after the dry pack is opened, or baking according to the MSL level guidelines to remove moisture. - Following a recommended reflow profile with a gradual preheat, controlled ramp to peak temperature (typically not exceeding 260°C for a few seconds), and controlled cooling to minimize thermal shock. - Ensuring the solder paste volume and stencil aperture design match the recommended land pattern to achieve reliable solder fillets without bridging or tombstoning.

6.2 Handling and Storage Precautions

• ESD Precautions: Handle in an ESD-protected environment using grounded wrist straps and conductive mats.
• Moisture Sensitivity: Store in the original moisture barrier bag with desiccant. Adhere to the MSL Level 3 floor life (168 hours at ≤ 30°C / 60% RH). If exceeded, bake at 125°C for 24 hours before use.
• Mechanical Stress: Avoid applying direct force to the LED lens. Use vacuum or soft-tipped tools for pick-and-place operations.
• Cleaning: If post-reflow cleaning is necessary, use mild, compatible solvents that do not attack the epoxy lens.

6.3 Storage Conditions

The device should be stored in a dry, cool environment within the specified storage temperature range of -40°C to +85°C. Long-term storage in high-humidity conditions should be avoided.

7. Packaging and Ordering Information

7.1 Standard Packaging Specifications

The device is supplied in tape-and-reel packaging suitable for automated assembly.

• Carrier Tape: Dimensions for the embossed carrier tape are specified, including pocket size, pitch, and tape width. This ensures compatibility with standard feeder systems.
• Reel Dimension: Details of the reel diameter, hub size, and maximum number of components per reel are provided for production planning.
• Label Specification: The reel label includes critical information such as part number, quantity, date code, and bin codes, facilitating traceability and inventory management.

7.2 Moisture-Resistant Packing

For moisture-sensitive components, the tape-and-reel is sealed inside a moisture barrier bag (MBB) with a humidity indicator card (HIC) and desiccant to maintain a low-humidity environment during storage and transit.

7.3 Outer Packaging

Multiple reels are packed in cardboard boxes for shipment, with specifications likely including box dimensions and packing density to prevent damage during logistics.

8. Application Recommendations and Design Considerations

8.1 Typical Application Circuits

The most common drive method is a series current-limiting resistor. The resistor value (R) is calculated using Ohm's Law: R = (V_supply - VF_LED) / IF, where VF_LED is the forward voltage at the desired current IF. Using the maximum VF from the bin ensures the current does not exceed limits even with component tolerances. For constant brightness across varying supply voltages or temperature, a simple constant current source (e.g., using a transistor or dedicated LED driver IC) is recommended.

8.2 Thermal Management in Design

Given the thermal resistance of 450°C/W, power dissipation must be carefully managed. For example, at the maximum continuous current of 20mA and a VF of 2.4V (max), power dissipation Pd = 0.020A * 2.4V = 48mW. The temperature rise from solder point to junction would be ΔT = Pd * RθJ-S = 0.048W * 450°C/W = 21.6°C. If the PCB temperature is 70°C, the junction temperature would be ~91.6°C, which is close to the maximum 95°C limit. Therefore, in high ambient temperature applications, derating the operating current is necessary.

8.3 Optical Design Considerations

The wide 140° viewing angle is ideal for omnidirectional indicators. For applications requiring a more directed beam, external lenses or light guides may be used. The yellow color is highly visible to the human eye and is often used for caution or attention-grabbing indicators.

9. Technical Comparison and Differentiation

While a direct side-by-side comparison with other products is not provided, key differentiating factors of this LED can be inferred from its specifications:

• Miniature Size (0402): Compared to larger packages like 0603 or 0805, this device enables higher PCB density, a critical advantage in miniaturized portable electronics.
• Comprehensive Binning: The multi-parameter binning (Vf, Wavelength, Intensity) offers designers greater control over color consistency and brightness matching in their end products compared to parts with looser or single-parameter sorting.
• Wide Viewing Angle: The 140° viewing angle is exceptionally wide for an SMD LED, providing better off-axis visibility than many competitors, which is valuable for panel-mounted indicators.
• Robust Thermal and ESD Specifications: The defined junction temperature, thermal resistance, and 2000V ESD rating provide clear design boundaries and suggest good reliability for industrial environments.

10. Frequently Asked Questions (Based on Technical Parameters)

10.1 How do I select the right current-limiting resistor?

Use the maximum forward voltage (VF) from your selected or expected bin in the calculation to ensure the current never exceeds the desired value, even with worst-case component variations. For a 5V supply and a target of 5mA using a C2 bin LED (VF max = 2.2V), R = (5V - 2.2V) / 0.005A = 560 Ohms. A standard 560Ω resistor would be suitable.

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

Yes, for most voltage bins. For example, with a VF of 2.0V (typical), a 3.3V supply provides sufficient headroom for a series resistor. The resistor value would be smaller, e.g., for 5mA: R = (3.3V - 2.0V) / 0.005A = 260 Ohms.

10.3 Why is the luminous intensity specified at 5mA instead of the maximum 20mA?

5mA is a standard test condition that allows for consistent comparison between different LED models and manufacturers. The intensity at higher currents can be estimated from the performance curves but may vary more due to thermal effects. Operating at lower currents also improves longevity and efficiency.

10.4 What happens if I exceed the maximum junction temperature?

Sustained operation above Tj max (95°C) will accelerate the degradation of the LED, leading to a permanent decrease in light output (lumen depreciation) and a possible shift in color over time. In extreme cases, it can cause catastrophic failure.

11. Practical Use Cases and Implementation Examples

11.1 Consumer Electronics: Smart Speaker Status Ring

Multiple yellow 0402 LEDs can be placed around the perimeter of a smart speaker to create a glowing status ring. The wide viewing angle ensures the light is visible from any direction in the room. The low power consumption and small size are perfect for such compact devices. Current would be set to a medium level (e.g., 10mA) using a bin with consistent intensity (e.g., D00) for uniform appearance.

11.2 Automotive Interior: Dashboard Button Backlighting

The LED's operating temperature range (-40°C to +85°C) makes it suitable for automotive interiors. It can be used to backlight climate control or infotainment buttons. The yellow color is often used for certain warning or function-specific indicators. Robustness against ESD and vibration (inherent in SMT assembly) is a key benefit here.

11.3 Industrial Control Panel: Fault Indicator

On a factory machine control panel, a cluster of these yellow LEDs could indicate a non-critical warning or standby mode. The high brightness bins (E00, F00) ensure visibility in well-lit industrial environments. The MSL Level 3 rating ensures it survives the typical SMT process used for control board manufacturing.

12. Operational Principle Introduction

Light Emitting Diodes (LEDs) are semiconductor devices that convert electrical energy directly into light through a process called electroluminescence. When a forward voltage is applied across the p-n junction, electrons from the n-type region recombine with holes from the p-type region in the active layer. This recombination releases energy in the form of photons (light particles). The specific wavelength (color) of the emitted light is determined by the energy bandgap of the semiconductor material used in the active region. For yellow light, materials like Aluminum Gallium Indium Phosphide (AlGaInP) are commonly used. The epoxy package serves to protect the delicate semiconductor chip, shape the light output beam, and provide the mechanical structure for soldering.

13. Industry Trends and Context

The market for SMD LEDs, especially in miniature packages like 0402 and smaller (e.g., 0201), continues to grow driven by the miniaturization of electronic devices. Key trends influencing components like this one include: - Increased Efficiency: Ongoing material science research aims to improve the luminous efficacy (lumens per watt) of colored LEDs, although yellow historically has lower efficacy than blue or white LEDs using phosphor conversion. - Higher Reliability Demands: As LEDs are used in more critical applications (automotive, medical), specifications for lifetime, color stability over time, and performance under harsh conditions become more stringent. - Integration and Smart Lighting: While this is a discrete component, the broader trend is towards integrated LED modules with built-in drivers and control logic. However, discrete LEDs like this one remain essential for simple indicator functions and flexible design where custom optical layouts are needed. - Tighter Color and Intensity Binning: To meet the demands of applications like large video walls or uniform backlighting, manufacturers are offering products with ever-tighter binning tolerances, a feature reflected in this component's detailed binning system.