SMD LED Yellow 120-Degree Viewing Angle - Electrical/Optical Characteristics - Automotive Accessories Application - Technical Documentation

1. Product Overview

This document provides comprehensive technical specifications for a high-performance Surface Mount Device (SMD) Light Emitting Diode (LED). This device is designed for reliability and performance in harsh environments, specifically targeting automotive accessory applications. Its miniature package size and standardized footprint make it suitable for automated Printed Circuit Board (PCB) assembly processes and space-constrained designs.

1.1 Core Features and Advantages

This LED integrates several key features that contribute to its robustness and ease of integration:

• Environmental Compliance:The product complies with the RoHS (Restriction of Hazardous Substances) Directive.
• Automated Handling:The devices are supplied in 12mm carrier tape on 7-inch diameter reels, compatible with standard automated pick-and-place equipment.
• High Reliability Standard:The devices are preconditioned to JEDEC Level 2 and qualified according to the AEC-Q101 Rev D standard, which is the benchmark for discrete semiconductor components in automotive applications.
• Process Compatibility:Designed to be compatible with infrared (IR) reflow soldering processes, which are standard in modern electronics manufacturing.
• Electrical Interface:The device is compatible with integrated circuits (I.C.), simplifying the design of the driving circuit.

1.2 Target Market and Applications

The primary intended applications areAutomotive accessory systemsThis includes interior and exterior lighting functions 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 indicator lights for various vehicle subsystems. The combination of high brightness, wide viewing angle, and automotive-grade certification makes it suitable for these applications.

2. Technical Parameters: In-depth and Objective Interpretation

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

2.1 Absolute Maximum Ratings

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

• Power Dissipation (Pd):530 mW. This is the maximum power the device can dissipate as heat.
• Peak Forward Current (I_F(PEAK)):400 mA. This is the maximum allowable pulse 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 current prevents overheating.
• Operating and Storage Temperature Range:-40°C to +110°C. This wide range is typical for automotive-grade components.
• Infrared Reflow Soldering Conditions:It can withstand 260°C for 10 seconds, which is consistent with common Pb-free reflow soldering profiles.

2.2 Thermal Characteristics

Thermal management is crucial for LED performance and lifespan. These parameters define how heat is conducted from the semiconductor junction.

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

2.3 Electrical and Optical Characteristics

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

• Luminous intensity (I_V):4.5 cd (minimum) to 11.2 cd (maximum). Measured using a sensor with a filter matched to the photopic (human eye) response curve (CIE). Actual values are binned (see Section 3).
• Viewing Angle (2θ_1/2):Typical value 120 degrees. This is the full angle at which the luminous intensity drops to half of its peak (on-axis) value. Such a wide viewing angle provides a broad, uniform illumination pattern.
• Peak Emission Wavelength (λ_P):Typical value 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. Binned for consistency.
• Spectral Line Half-Width (Δλ):Typical value 18 nm. This indicates spectral purity; a narrower width means more saturated and purer color.
• Forward voltage (V_F):At 140mA, 1.90 V (minimum) to 2.65 V (maximum). This is the voltage drop across the LED during operation. Binning is performed to assist circuit design.
• Reverse current (I_R):In V_R= 12V, maximum is 10 μA. This device is not designed for reverse bias operation; this parameter is for test purposes only.

3. Grading System Description

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

3.1 Forward Voltage (Vf) Grading

Binning ensures that LEDs have similar voltage drops, which is crucial for current sharing in parallel circuits or predictable driver design.

• Gear Code: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 according to their light output brightness.

• Gear Code: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% i kowane matakin.

3.3 Dominant Wavelength (Wd) Grading

Wannan yana tabbatar da daidaiton fahimtar rawaya tsakanin nau'ikan samarwa daban-daban.

• Gear Code:3 (583-586 nm), 4 (586-589 nm), 5 (589-592 nm), 6 (592-595 nm).
• Tolerance:±1 nm within each gear.

4. Performance Curve Analysis

Graphical data provides in-depth insights into the behavior of LEDs under various conditions.

4.1 Spatial Distribution (Beam Pattern)

The provided polar plot (Figure 2) visually illustrates the 120-degree viewing angle. It shows the relative luminous intensity as a function of the angle from the central axis. For such wide-viewing-angle LEDs, the pattern is typically Lambertian or near-Lambertian, meaning the intensity decreases with the cosine of the angle.

4.2 Forward Current vs. Forward Voltage / Luminous Intensity

Although no explicit graph is provided in the excerpt, typical curves for AlInGaP LEDs show a non-linear relationship. The forward voltage (V_F) increases logarithmically with current. The luminous intensity (I_VWithin a certain range, it is usually directly proportional to the forward current. Beyond this range, efficiency decreases 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 sensitive to temperature. As the junction temperature increases:

• Forward voltage (V_F):Slightly decreases (negative temperature coefficient).
• Luminous intensity (I_V):Descent. Light output will significantly decrease at high temperatures, which is why thermal management (low R_θJS) is crucial.
• Dominant Wavelength (λ_d):A slight shift may occur, potentially affecting perceived color, especially in applications with strict binning requirements.

5. Mechanical and Packaging Information

5.1 Package Dimensions and Polarity Identification

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

5.2 Recommended PCB Mounting Pad Design

A pad pattern diagram for infrared reflow soldering is provided. Following this recommendation is crucial for achieving proper solder joint formation, ensuring good electrical connection, and (critically) maximizing heat transfer from the anode/thermal pad to the PCB copper layer. The size and shape of this pad directly affect the effective thermal resistance (R_θJS).

6. Soldering and Assembly Guide

6.1 Infrared Reflow Soldering Profile

Specifies a detailed reflow profile diagram, compliant with the J-STD-020 lead-free process standard. Key parameters include:

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

6.2 Manual Welding (if necessary)

If manual rework is required:

• Iron temperature:Maximum 300°C.
• Soldering time:Kowane ɗanɗano ya fi tsawon daƙiƙa 3.
• Adadin gyare-gyare:Yin walda da hannu ya iyakance sau ɗaya kawai, don rage matsin zafi.

6.3 Cleaning

If post-soldering cleaning is required, only specified solvents should be used to avoid damaging the LED package. Ethanol or isopropyl alcohol is recommended. The LED should be immersed at room temperature for less than one minute.

7. Storage and Handling Precautions

7.1 Moisture Sensitivity

According to JEDEC J-STD-020, this product is classified asMoisture Sensitivity Level (MSL) 2。

• Sealed packaging:Store at ≤30°C and ≤70% relative humidity (RH). When stored in the original moisture barrier bag with desiccant, the shelf life is one year from the date code.
• Opened packaging:For components removed from sealed bags, the storage environment must not exceed 30°C and 60% RH. It is recommended to complete infrared reflow soldering within 365 days after opening.
• Long-term storage (opened):Store in a sealed container with desiccant or in a nitrogen dryer.
• Baking:If components are 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 "popcorn" damage during reflow.

7.2 Application Considerations

This LED is designed for general electronic and automotive accessory equipment. For applications where failure could directly endanger life or health (e.g., aviation primary systems, medical life support, critical safety equipment), specific reliability assessments and consultation with the manufacturer are required before design adoption.

8. Packaging and Ordering Information

8.1 Carrier Tape and Reel Specifications

Devices are supplied in industry-standard embossed carrier tape format.

• Carrier tape width:12 mm.
• Reel diameter:Inchi 7 (178 mm).
• Idadi kwa kila spool:Kawaida vipande 1000, kiwango cha chini cha agizo kwa spool ni vipande 500.
• Cover Tape:The cavity is sealed with top cover tape.
• Missing Component:According to the specification, a maximum of two consecutive missing LEDs (holes) is allowed.
• Standard:Packaging complies with ANSI/EIA-481 specification.

8.2 Label Information

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

9. Application Suggestions and Design Considerations

9.1 Typical Application Scenarios

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

9.2 Key Design Considerations

1. Thermal Management:This is the most critical aspect. The PCB layout must maximizeAnode padthe size and thermal connectivity (using vias to connect to inner or backside copper layers), as it is the primary thermal path. Failure to do this will result in higher junction temperature, reduced light output, accelerated lumen depreciation, and shorter lifespan.
2. Current drive:Use a constant current drive circuit, rather than a simple current-limiting resistor connected to a variable voltage source, to achieve stable and consistent light output. Ensure the driver can provide the required current (5-200mA DC) and can handle the forward voltage bin of the LED used.
3. Optical Design:A 120-degree viewing angle provides broad, diffuse light. For a focused beam, secondary optics (lenses) are required. "Water clear" lens means the LED emits the native yellow light without diffusion.
4. ESD Protection:Although not explicitly stated as sensitive devices, implementing basic ESD protection on the control lines driving LEDs is a good practice for enhancing robustness.

10. Technical Comparison and Differentiation

Although this specification does not provide a direct side-by-side comparison with other models, the key differentiating points of this LED can be inferred from its specifications:

• Compared to standard commercial LEDs:The main differences lie inAEC-Q101 CertificationAnd an extended temperature range (-40°C to +110°C), making it suitable for automotive environments where extreme temperatures and vibrations are common.
• Compared to narrow-angle LEDs:其120-degree viewing angleMuch wider than many indicator LEDs (which may be 30-60 degrees), making it more suitable for area lighting or applications where the LED might be viewed from off-axis angles.
• Compared to unbinned LEDs:ComprehensiveThree-parameter binning (Vf, Iv, Wd)It ensures high consistency in brightness, color, and electrical behavior within a production batch, which is crucial 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 at which an LED emits the most optical power. Dominant wavelength (λ_d) is a calculated value based on the entire emission spectrum and the CIE color-matching functions, representing the color perceived by the human eye. λ_dIt is more relevant for color specification.

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

Q3: Ina iya amfani da wutar lantarki 12V da resistor don kunna wannan LED?
A: A fasaha zai yiwu, amma ba a ba da shawarar don mafi kyawun aiki ko dogaro ba. Lissafin R = (12V - V_F) / I_Fyana da sauƙi, amma kowane canji a cikin ƙarfin wutar lantarki ko ƙarfin LED na gaba (sabon rarrabuwa ko zafin jiki) zai haifar da babban canji a cikin halin yanzu da haske. Ana ba da shawarar sosai amfani da direban halin yanzu na dindindin.

Q4: The anode is the heat sink. Does this mean the cathode pad is thermally insignificant?
A: Correct. The primary thermal path is intentionally designed through the anode. Although the cathode connection also conducts some heat, the PCB layout should concentrate thermal management measures (large copper area, thermal vias) entirely on the anode pad for maximum effectiveness.

12. Practical Design and Usage Cases

Scenario: Designing the ambient light strip for the car's center console.

1. Requirements Analysis:Uniform, soft yellow lighting needs to be achieved on a 30cm long light strip, visible from different seating positions. Operating voltage is the vehicle's nominal 12V system. Temperature environment ranges from cold start to hot cabin.
2. Component Selection:This LED is suitable due to its automotive-grade, wide viewing angle (for uniform diffusion), and yellow color. High brightness allows it to be driven below maximum current for higher efficiency and longer life.
3. Circuit Design:Select a switching constant-current LED driver IC, configured to provide 100mA per LED. This is below the 140mA test point, providing margin for thermal derating. The driver's current setting is independent of fluctuations in the vehicle's 9-16V electrical system.
4. PCB Layout:The design employs a linear LED array. The most critical step is to design a large solid copper pour area for the anode pad of each LED, connected via multiple thermal vias to a dedicated internal ground plane serving as a heat sink. The cathode pads are connected using thin traces.
5. Optical Integration:LED is placed behind a milky or textured light guide plate/diffuser, scattering the 120-degree beam into completely uniform light, hiding the individual LED "hot spots".
6. Verification:Test components across the entire temperature range to ensure that light output meets requirements at high temperatures and that condensation-related failures do not occur during humidity cycling (verification followed the MSL-2 handling procedure).

13. Technical Introduction

This LED utilizesAlInGaPSemiconductor material system. This material is particularly efficient in generating light in the yellow, orange, red, and amber regions of the spectrum. The main advantages of AlInGaP include high internal quantum efficiency and good temperature stability compared to some other material systems. "Water clear" lenses are typically made from high-temperature epoxy or silicone that is transparent to the emitted wavelength, allowing the pure color of the semiconductor chip to be seen without alteration or diffusion.

14. Industry Trends and Development

The overall trend for SMD LEDs, especially for automotive and industrial applications, is moving in the following directions:

1. Improving efficiency (lm/W):Continuous improvements in epitaxial growth and chip design generate more light output from the same electrical input, thereby reducing power consumption and thermal load.
2. Higher power density and improved thermal management:The new package design integrates improved thermal pathways (such as the dedicated anode heatsink here) and materials to handle higher drive currents within a smaller footprint.
3. Enhanced reliability and stringent certification:Standards like AEC-Q101 are continuously revised, requiring components to pass more rigorous testing for longer lifespans, especially in automotive applications where 10-15 years of service life is common.
4. Stricter binning and color consistency:As applications like ambient lighting become more aesthetically focused, the 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 circuits, and sometimes optical elements into a single, smarter "LED module" to simplify end-user design.