SMD LED Yellow 120-Degree Viewing Angle - Electrical/Optical Characteristics - Automotive Accessory Applications - English Technical Document

1. Product Overview

This document provides comprehensive technical specifications for a high-performance Surface-Mount Device (SMD) Light Emitting Diode (LED). The device is engineered for reliability and performance in demanding environments, specifically targeting accessory applications within the automotive sector. Its miniature form factor and standardized package make it suitable for automated printed circuit board (PCB) assembly processes and space-constrained designs.

1.1 Core Features and Advantages

The LED incorporates several key features that contribute to its robustness and ease of integration:

• Environmental Compliance: The product is compliant with RoHS (Restriction of Hazardous Substances) directives.
• Automated Handling: It is supplied packaged in 12mm tape on 7-inch diameter reels, compatible with standard automated pick-and-place equipment.
• High-Reliability Standards: The device undergoes preconditioning accelerated to JEDEC Level 2 and is qualified according to the AEC-Q101 Rev D standard, which is the benchmark for discrete semiconductor components in automotive applications.
• Process Compatibility: It is designed to be compatible with infrared (IR) reflow soldering processes, which are standard in modern electronics manufacturing.
• Electrical Interface: The device is I.C. (Integrated Circuit) compatible, simplifying drive circuit design.

1.2 Target Market and Applications

The primary intended application is for automotive accessory systems. This includes interior and exterior lighting features that are not part of the core safety-critical lighting systems (e.g., headlights, brake lights). Examples may include dashboard indicator lights, ambient lighting, puddle lights, or status indicators for various vehicle subsystems. The combination of high brightness, a wide viewing angle, and automotive-grade qualification makes it suitable for these purposes.

2. Technical Parameters: In-Depth Objective Interpretation

This section provides a detailed breakdown of the device's electrical, optical, and thermal characteristics. All parameters are specified at an ambient temperature (Ta) of 25°C unless otherwise stated.

2.1 Absolute Maximum Ratings

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

• Power Dissipation (Pd): 530 mW. This is the maximum amount of power the device can dissipate as heat.
• Peak Forward Current (I_F(PEAK)): 400 mA. This is the maximum allowable pulsed current, typically defined under specific conditions (1/10 duty cycle, 0.1ms pulse width) to manage junction temperature.
• DC Forward Current (I_F): 5 mA to 200 mA. This is the recommended range for continuous operation. The minimum current ensures stable light output, while the maximum prevents overheating.
• Operating & Storage Temperature Range: -40°C to +110°C. This wide range is characteristic of automotive-grade components.
• Infrared Soldering Condition: Withstands 260°C for 10 seconds, which aligns with common lead-free (Pb-free) reflow soldering profiles.

2.2 Thermal Characteristics

Thermal management is critical for LED performance and longevity. These parameters define how heat travels from the semiconductor junction.

• Thermal Resistance, Junction-to-Ambient (R_θJA): Typical 50 °C/W. Measured on an FR4 PCB (1.6mm thick) with a 16mm² copper pad. This value indicates how much the junction temperature rises for every watt of power dissipated, relative to the ambient air.
• Thermal Resistance, Junction-to-Solder Point (R_θJS): Typical 30 °C/W. This is often a more useful metric as it describes the thermal path to the PCB, which is the primary heat sink. A lower value is better.
• Maximum Junction Temperature (T_J): 125 °C. The absolute upper limit for the temperature at the semiconductor junction.

2.3 Electrical and Optical Characteristics

These are the typical performance parameters under standard test conditions (I_F = 140mA, Ta=25°C).

• Luminous Intensity (I_V): 4.5 cd (Min) to 11.2 cd (Max). Measured using a sensor filtered to match the photopic (human eye) response curve (CIE). The actual value is binned (see Section 3).
• Viewing Angle (2θ_1/2): Typical 120 degrees. This is the full angle at which the luminous intensity drops to half of its peak (on-axis) value. A wide viewing angle like this provides a broad, even illumination pattern.
• Peak Emission Wavelength (λ_P): Typical 592 nm. This is the wavelength at which the spectral power output is highest.
• Dominant Wavelength (λ_d): 583 nm to 595 nm. This is the single wavelength that best represents the perceived color of the light, derived from the CIE chromaticity diagram. It is binned for consistency.
• Spectral Line Half-Width (Δλ): Typical 18 nm. This indicates the spectral purity; a narrower width means a more saturated, pure color.
• Forward Voltage (V_F): 1.90 V (Min) to 2.65 V (Max) at 140mA. This is the voltage drop across the LED when operating. It is binned to aid in circuit design.
• Reverse Current (I_R): Maximum 10 μA at V_R = 12V. The device is not designed for reverse bias operation; this parameter is for test purposes only.

3. Binning System Explanation

To ensure consistent color and performance in production, LEDs are sorted into bins based on key parameters. The batch code follows the format: Vf / Iv / Wd (e.g., D/DA/3).

3.1 Forward Voltage (Vf) Binning

Bins ensure LEDs have similar voltage drops, which is important for current-sharing in parallel circuits or for predictable driver design.

• Bin Codes: C (1.90-2.05V), D (2.05-2.20V), E (2.20-2.35V), F (2.35-2.50V), G (2.50-2.65V).
• Tolerance: ±0.1V within each bin.

3.2 Luminous Intensity (Iv) Binning

This groups LEDs by their light output brightness.

• Bin Codes: DA (4.5-5.6 cd), DB (5.6-7.1 cd), EA (7.1-9.0 cd), EB (9.0-11.2 cd).
• Tolerance: ±11% within each bin.

3.3 Dominant Wavelength (Wd) Binning

This ensures a consistent perceived yellow color across production lots.

• Bin Codes: 3 (583-586 nm), 4 (586-589 nm), 5 (589-592 nm), 6 (592-595 nm).
• Tolerance: ±1 nm within each bin.

4. Performance Curve Analysis

Graphical data provides insight into how the LED behaves under varying conditions.

4.1 Spatial Distribution (Beam Pattern)

The provided polar diagram (Fig. 2) visually represents the 120-degree viewing angle. It shows the relative luminous intensity as a function of the angle from the central axis. The pattern is typically Lambertian or near-Lambertian for such wide-viewing-angle LEDs, meaning intensity falls off with the cosine of the angle.

4.2 Forward Current vs. Forward Voltage / Luminous Intensity

While not explicitly graphed in the provided excerpt, typical curves for AlInGaP LEDs show a non-linear relationship. Forward voltage (V_F) increases logarithmically with current. Luminous intensity (I_V) is generally proportional to forward current up to a point, after which efficiency droop occurs due to increased heat and other semiconductor effects. Operating at the recommended 140mA is likely within the high-efficiency region.

4.3 Temperature Dependence

LED performance is temperature-sensitive. As junction temperature increases:

• Forward Voltage (V_F): Decreases slightly (negative temperature coefficient).
• Luminous Intensity (I_V): Decreases. The light output can drop significantly at high temperatures, which is why thermal management (low R_θJS) is crucial.
• Dominant Wavelength (λ_d): May shift slightly, potentially affecting perceived color, especially in tightly binned applications.

5. Mechanical and Package Information

5.1 Package Dimensions and Polarity Identification

The LED uses a standard EIA package outline. Critical dimensions include length, width, and height, with a typical tolerance of ±0.2mm. A key design note is that the ANODE lead frame also serves as the primary heat sink for the LED. This means the anode pad on the PCB should be designed to maximize thermal dissipation, as it is the main path for heat to leave the LED junction and enter the PCB.

5.2 Recommended PCB Attachment Pad Design

A land pattern diagram is provided for IR reflow soldering. Following this recommendation is essential for achieving proper solder joint formation, ensuring good electrical connection, and, critically, maximizing thermal transfer from the anode/heat sink pad to the PCB's copper layers. The size and shape of this pad directly influence the effective thermal resistance (R_θJS).

6. Soldering and Assembly Guidelines

6.1 IR Reflow Soldering Profile

A detailed reflow profile graph is specified, compliant with J-STD-020 for lead-free processes. Key parameters include:

• Pre-heat: Ramp-up to 150-200°C.
• Soak/Pre-heat Time: Maximum 120 seconds to allow for temperature stabilization and flux activation.
• Peak Temperature: Maximum 260°C.
• Time Above Liquidus (TAL): The time spent above the solder's melting point is critical; the profile ensures it is within limits (typically 60-90 seconds) to form reliable joints without thermal damage to the component.
• Number of Passes: Maximum of two reflow cycles.

6.2 Hand Soldering (If Necessary)

If manual rework is required:

• Soldering Iron Temperature: Maximum 300°C.
• Soldering Time: Maximum 3 seconds per joint.
• Number of Repairs: One time only for hand soldering to minimize thermal stress.

6.3 Cleaning

If post-solder cleaning is necessary, only specified solvents should be used to avoid damaging the LED package. Recommended agents are ethyl alcohol or isopropyl alcohol. The LED should be immersed at normal temperature for less than one minute.

7. Storage and Handling Cautions

7.1 Moisture Sensitivity

This product is classified as Moisture Sensitivity Level (MSL) 2 per JEDEC J-STD-020.

• Sealed Package: Store at ≤30°C and ≤70% Relative Humidity (RH). Shelf life is one year from the date code when stored in the original moisture-proof bag with desiccant.
• Opened Package: For components removed from the sealed bag, the storage environment must not exceed 30°C and 60% RH. It is recommended to complete IR reflow soldering within 365 days of opening.
• Extended Storage (Opened): Store in a sealed container with desiccant or in a nitrogen desiccator.
• Baking: If components have been exposed to ambient conditions for more than 365 days, they must be baked at approximately 60°C for at least 48 hours prior to soldering to remove absorbed moisture and prevent \"popcorning\" damage during reflow.

7.2 Application Caution

The LED is designed for ordinary electronic and automotive accessory equipment. For applications where failure could directly jeopardize life or health (e.g., aviation primary systems, medical life support, critical safety devices), a specific reliability assessment and consultation with the manufacturer are required prior to design-in.

8. Packaging and Ordering Information

8.1 Tape and Reel Specifications

The device is supplied in industry-standard embossed carrier tape.

• Tape Width: 12 mm.
• Reel Diameter: 7 inches (178 mm).
• Quantity per Reel: Standard 1000 pieces, with a minimum order quantity of 500 pieces per reel.
• Cover Tape: Empty pockets are sealed with a top cover tape.
• Missing Components: A maximum of two consecutive missing LEDs (empty pockets) is allowed per specification.
• Standard: Packaging conforms to ANSI/EIA-481 specifications.

8.2 Label Information

The reel label includes the batch description code in the format Vf_Bin/Iv_Bin/Wd_Bin (e.g., D/DA/3), allowing traceability of the electrical and optical characteristics of the lot.

9. Application Suggestions and Design Considerations

9.1 Typical Application Scenarios

• Automotive Interior: Dashboard indicator lights, gear shift position indicators, audio system status lights, ambient footwell or console lighting.
• Automotive Exterior: Puddle lights, door handle illumination, non-critical marker or accent lighting.
• General Indicator Use: Status LEDs in other transportation or industrial equipment where wide viewing angle and high brightness are beneficial.

9.2 Critical Design Considerations

1. Thermal Management: This is the most critical aspect. The PCB layout must maximize the size and thermal connectivity (using vias to inner or back-plane copper layers) of the anode pad, as it is the main thermal path. Failure to do so will lead to higher junction temperatures, reduced light output, accelerated lumen depreciation, and shorter lifespan.
2. Current Driving: Use a constant-current driver circuit, not a simple current-limiting resistor connected to a variable voltage source, for stable and consistent light output. Ensure the driver can supply the required current (5-200mA DC) and can handle the forward voltage bin of the LEDs used.
3. Optical Design: The 120-degree viewing angle provides broad, diffuse light. For focused beams, secondary optics (lenses) would be required. The \"water clear\" lens means the LED emits the native yellow color without diffusion.
4. ESD Protection: While not explicitly stated as sensitive, implementing basic ESD protection on control lines driving the LED is a good practice for robustness.

10. Technical Comparison and Differentiation

While a direct side-by-side comparison with other part numbers is not provided in this datasheet, the key differentiators of this LED can be inferred from its specifications:

• vs. Standard Commercial LEDs: The primary differentiator is AEC-Q101 qualification and the extended temperature range (-40°C to +110°C), making it suitable for automotive environments where temperature extremes and vibration are common.
• vs. Narrow-Angle LEDs: The 120-degree viewing angle is significantly wider than many indicator LEDs (which may be 30-60 degrees), making it better for area illumination or applications where the LED may be viewed from off-axis angles.
• vs. Non-Binned LEDs: The comprehensive three-parameter binning (Vf, Iv, Wd) ensures much higher consistency in brightness, color, and electrical behavior within a production run, which is essential for applications requiring uniform appearance or predictable circuit performance.

11. Frequently Asked Questions (Based on Technical Parameters)

Q1: What is the difference between Peak Wavelength and Dominant Wavelength?
A: Peak Wavelength (λ_P) is the physical wavelength where the LED emits the most optical power. Dominant Wavelength (λ_d) is a calculated value that represents the perceived color by the human eye, based on the entire emission spectrum and the CIE color matching functions. λ_d is more relevant for color specification.

Q2: Why is there a minimum forward current (5mA)?
A: At very low currents, the light output of an LED can become unstable and non-linear. Specifying a minimum ensures the device operates in a predictable and stable region of its performance curve.

Q3: Can I drive this LED with a 12V supply and a resistor?
A: Technically yes, but it is not recommended for optimal performance or reliability. The calculation R = (12V - V_F) / I_F is simple, but any variation in the supply voltage or the LED's forward voltage (due to binning or temperature) will cause a large variation in current and thus brightness. A constant-current driver is strongly preferred.

Q4: The anode is the heat sink. Does this mean the cathode pad is not thermally important?
A> Correct. The primary thermal path is intentionally designed through the anode. While the cathode connection will conduct some heat, the PCB layout should focus thermal management efforts (large copper area, thermal vias) exclusively on the anode pad for maximum effectiveness.

12. Practical Design and Usage Case

Scenario: Designing an automotive center console ambient light strip.

1. Requirements Analysis: Need uniform, soft yellow illumination across a 30cm strip, visible from various seating positions. Operating voltage is the vehicle's 12V nominal system. Temperature environment ranges from cold starts to a hot cabin.
2. Component Selection: This LED is suitable due to its automotive grade, wide viewing angle (for even diffusion), and yellow color. The high brightness allows it to be driven below its maximum current for higher efficiency and longer life.
3. Circuit Design: A switching constant-current LED driver IC is selected, configured to deliver 100mA per LED. This is below the 140mA test point, providing headroom for thermal derating. The driver's current setting is independent of the vehicle's 9-16V electrical system fluctuations.
4. PCB Layout: The design uses a linear array of LEDs. The most critical step is designing a large, solid copper pour for the anode pad of each LED, connected through multiple thermal vias to a dedicated internal ground plane that acts as a heat spreader. The cathode pads are connected with thin traces.
5. Optical Integration: The LEDs are placed behind a milky-white or textured light guide/diffuser to scatter the 120-degree beam into a perfectly even line of light, hiding individual LED \"hot spots.\"
6. Validation: The assembly is tested across the temperature range to ensure light output meets requirements when hot and that no condensation-related failures occur during humidity cycling (validating MSL-2 handling procedures were followed).

13. Technology Introduction

This LED utilizes an AlInGaP (Aluminum Indium Gallium Phosphide) semiconductor material system. This material is particularly efficient at producing light in the yellow, orange, red, and amber regions of the spectrum. Key advantages of AlInGaP include high internal quantum efficiency and good temperature stability compared to some other material systems. The \"water clear\" lens is typically made of a high-temperature epoxy or silicone that is transparent to the emitted wavelength, allowing the pure color of the semiconductor die to be seen without alteration or diffusion.

14. Industry Trends and Developments

The general trend in SMD LEDs, particularly for automotive and industrial applications, is towards:

1. Increased Efficiency (lm/W): Ongoing improvements in epitaxial growth and chip design yield more light output for the same electrical input, reducing power consumption and thermal load.
2. Higher Power Density and Improved Thermal Management: New package designs incorporate better thermal paths (like the dedicated anode heat sink here) and materials to handle higher drive currents in smaller footprints.
3. Enhanced Reliability and Stringent Qualification: Standards like AEC-Q101 are continuously revised, and components are expected to meet more rigorous testing for longer lifetimes, especially in automotive applications where 10-15 year lifespans are common.
4. Tighter Binning and Color Consistency: As applications like ambient lighting become more aesthetic, demand for LEDs with extremely consistent color coordinates (beyond simple dominant wavelength) and intensity across production batches is increasing.
5. Integration: There is a trend towards integrating multiple LED chips, control circuitry, and sometimes optics into single, smarter \"LED modules\" to simplify end-user design.