ALFS1J-C0 LED Datasheet - SMD Ceramic Package - 425lm @1000mA - 3.25V - 120° Viewing Angle - English Technical Document

1. Product Overview

The ALFS1J-C0 is a high-power, surface-mount LED designed specifically for demanding automotive exterior lighting applications. It is housed in a robust ceramic package, offering excellent thermal management and reliability under harsh environmental conditions. The device is qualified according to AEC-Q102 standards, ensuring it meets the stringent requirements for automotive electronic components. Its primary applications include headlamps, daytime running lights (DRL), and fog lamps, where consistent performance, high luminous output, and long-term durability are critical.

The core advantages of this LED include a high typical luminous flux of 425 lumens at a drive current of 1000mA, a wide 120-degree viewing angle for good light distribution, and robust construction with ESD protection up to 8 kV (HBM). It is also compliant with RoHS, REACH, and halogen-free regulations, making it suitable for global automotive markets. The product's sulfur robustness is classified as A1, indicating high resistance to corrosive sulfur-containing atmospheres commonly found in automotive environments.

2. Technical Parameters Deep Objective Interpretation

2.1 Photometric and Electrical Characteristics

The key operational parameters are defined under a test condition of a forward current (I_F) of 1000mA with the thermal pad maintained at 25°C. The typical luminous flux (Φ_v) is 425 lm, with a minimum of 400 lm and a maximum of 500 lm, subject to a measurement tolerance of ±8%. The forward voltage (V_F) typically measures 3.25V, ranging from 2.90V to 3.80V (±0.05V tolerance). The dominant wavelength or correlated color temperature (CCT) falls within a range of 5391K to 6893K, classifying it as a cool white LED. The viewing angle is specified as 120 degrees, with a tolerance of ±5°.

2.2 Absolute Maximum Ratings and Thermal Characteristics

These ratings define the limits beyond which permanent damage may occur. The absolute maximum forward current is 1500 mA. The device is not designed for reverse voltage operation. The maximum junction temperature (T_J) is 150°C, with an operating temperature range of -40°C to +125°C. The thermal resistance from the junction to the solder point is a critical parameter for heat dissipation. The real thermal resistance (R_{th JS real}) is typ. 4.0 K/W (max 4.4 K/W), while the electrical equivalent (R_{th JS el}) is typ. 3.0 K/W (max 3.4 K/W). The maximum power dissipation is 5700 mW.

3. Binning System Explanation

To ensure color and brightness consistency in production, LEDs are sorted into bins based on key parameters.

3.1 Luminous Flux Binning

Luminous flux is binned in groups, with the provided data showing Group "C". Within this group, bins are defined: Bin 6 (400-425 lm), Bin 7 (425-450 lm), Bin 8 (450-475 lm), and Bin 9 (475-500 lm). The test is performed at the typical forward current with a 25ms pulse, and measurement tolerance is ±8%.

3.2 Forward Voltage Binning

Forward voltage is categorized into three groups: Group 1A (2.90V - 3.20V), Group 1B (3.20V - 3.50V), and Group 1C (3.50V - 3.80V). This allows designers to select LEDs with similar V_F for better current matching in multi-LED arrays. The measurement tolerance is ±0.05V.

3.3 Color (Chromaticity) Binning

The color coordinates on the CIE 1931 chromaticity diagram are binned into specific regions. The datasheet shows bins for cool white LEDs, including 63M, 61M, 58M, 56M, 65L, 65H, 61L, and 61H. Each bin is defined by a quadrilateral area on the x,y coordinate plot. For example, Bin 63M covers coordinates approximately from (0.3127, 0.3093) to (0.3212, 0.3175). The coordinate measurement tolerance is ±0.005.

4. Performance Curve Analysis

4.1 Forward Current vs. Forward Voltage (IV Curve)

The graph shows the non-linear relationship between forward current and forward voltage at 25°C. The curve is typical for a power LED, with voltage increasing logarithmically with current. This data is essential for designing the driver circuit to ensure the LED operates within its specified voltage range at the desired current.

4.2 Relative Luminous Flux vs. Forward Current

This graph illustrates light output relative to the value at 1000mA as a function of drive current. Luminous flux increases with current but may exhibit sub-linear growth at higher currents due to efficiency droop and increased junction temperature.

4.3 Thermal Performance Graphs

Several graphs depict performance versus junction temperature (T_J) at I_F=1000mA. The Relative Luminous Flux vs. Junction Temperature curve shows the light output decreasing as temperature rises, a characteristic known as thermal quenching. The Relative Forward Voltage vs. Junction Temperature curve shows V_F decreasing linearly with increasing temperature, which can be used for junction temperature estimation. The Chromaticity Coordinates Shift vs. Junction Temperature graph shows how the color point (CIE x, y) changes with temperature, which is crucial for color-critical applications.

4.4 Forward Current Derating Curve

This is a critical design graph. It plots the maximum allowable forward current against the solder pad temperature (T_S). As T_S increases, the maximum permissible current must be reduced to prevent the junction temperature from exceeding 150°C. The curve provides specific derating points: e.g., at T_S=110°C, I_F can be 1500mA; at T_S=125°C, I_F must be reduced to 1200mA. Operation below 50mA is not recommended.

4.5 Spectral Distribution

The relative spectral power distribution graph shows the intensity of light emitted across wavelengths from approximately 400nm to 800nm at 25°C and 1000mA. It characterizes the LED's cool white light, typically produced by a blue LED chip combined with a phosphor layer.

5. Mechanical and Package Information

The LED uses a surface-mount device (SMD) ceramic package. Ceramic offers superior thermal conductivity compared to plastic packages, facilitating better heat transfer from the LED junction to the printed circuit board (PCB). This is vital for maintaining performance and longevity in high-power applications like automotive lighting. The specific mechanical dimensions, including length, width, height, and pad locations, are detailed in the mechanical drawing section of the datasheet. The package includes a thermal pad for efficient soldering to a thermal land on the PCB.

6. Soldering and Assembly Guidelines

6.1 Recommended Soldering Pad Layout

A recommended land pattern (footprint) for PCB design is provided. This pattern ensures proper solder joint formation, electrical connection, and most importantly, optimal thermal transfer from the LED's thermal pad to the PCB's copper plane. Adhering to this layout is crucial for reliability.

6.2 Reflow Soldering Profile

The datasheet specifies a reflow soldering profile with a peak temperature of 260°C. This profile defines the time-temperature curve that the assembly must follow during the reflow process. Key parameters include preheat, soak, reflow, and cooling rates and durations. Following this profile prevents thermal shock to the ceramic package and ensures reliable solder joints without damaging the internal LED structure.

6.3 Precautions for Use

General handling and usage precautions are outlined. These include warnings against applying reverse voltage, exceeding absolute maximum ratings, and improper soldering techniques. It also emphasizes the importance of static discharge (ESD) protection during handling, even though the device has built-in ESD protection up to 8kV.

7. Packaging and Ordering Information

The product is supplied in tape and reel packaging suitable for automated pick-and-place assembly machines. Packaging information details the reel dimensions, tape width, pocket spacing, and orientation of the components on the tape. The part number structure (e.g., ALFS1J-C010001H-AM) encodes specific attributes such as the series, bin codes for flux and color, and other variant information. Ordering information guides the user on how to specify the desired bin combinations when placing an order.

8. Application Suggestions

8.1 Typical Application Scenarios

The primary designed applications are Automotive Exterior Lighting systems. This includes:
- Headlamps (Low/High Beam): Where high luminous intensity and precise beam control are required.
- Daytime Running Lights (DRL): Requiring high efficiency and visibility.
- Fog Lamps: Needing good penetration in adverse weather conditions.
The wide viewing angle and high flux make it suitable for both primary light sources and supplementary lighting functions.

8.2 Design Considerations

1. Thermal Management: This is the most critical aspect. The PCB must have an adequate thermal design—using thick copper layers, thermal vias, and possibly an external heatsink—to keep the solder pad temperature (T_S) as low as possible. Refer to the derating curve for current limits.
2. Drive Current: While the LED can be driven up to 1500mA, operating at or below the typical 1000mA provides a better balance of light output, efficiency, and thermal load, enhancing long-term reliability.
3. Optical Design: The 120° viewing angle requires appropriate secondary optics (lenses, reflectors) to shape the beam for the specific application (e.g., a focused beam for headlights).
4. Electrical Design: Use a constant-current LED driver compatible with the forward voltage bin. For arrays, consider bin selection and possible use of current-balancing techniques.

9. Technical Comparison and Differentiation

Compared to standard commercial or industrial LEDs, the ALFS1J-C0 offers several key differentiators essential for automotive use:
- AEC-Q102 Qualification: This is a mandatory reliability standard for automotive LEDs, involving rigorous tests for temperature cycling, humidity, solder heat resistance, and more.
- Ceramic Package: Provides better thermal performance and long-term stability under high temperature and humidity than plastic packages (e.g., PPA, PCT).
- Sulfur Robustness (Class A1): Specifically tested and guaranteed to resist corrosion from sulfur-containing gases, a common failure mode in automotive environments.
- High ESD Rating (8kV HBM): Offers greater protection against electrostatic discharge during handling and assembly.
- Extended Temperature Range (-40°C to +125°C): Guarantees operation in the extreme temperatures encountered by vehicles.

10. Frequently Asked Questions (Based on Technical Parameters)

Q: What is the actual light output I can expect from Bin C7?
A: Bin C7 specifies a luminous flux range of 425-450 lm when measured at I_F=1000mA and T_s=25°C. Considering the ±8% measurement tolerance, the actual measured value for a specific LED could be between approximately 391 lm and 486 lm under those ideal test conditions. In a real application with higher temperature, the output will be lower.

Q: How do I determine the required heatsink based on the thermal data?
A: You need to perform a thermal calculation. The key parameter is the real thermal resistance, R_{th JS real} (typ. 4.0 K/W). This is the resistance from the junction to the solder point. You must add the thermal resistance from the solder point to the ambient (through the PCB, thermal interface material, and heatsink) to calculate the total R_{th JA}. Using the formula T_J = T_A + (R_{th JA} × Power Dissipation), you can ensure T_J remains below 150°C, preferably with a safety margin. The derating curve provides a simplified guide based on solder pad temperature.

Q: Can I drive this LED with a constant voltage source?
A: It is strongly discouraged. LEDs are current-driven devices. Their forward voltage has a negative temperature coefficient and varies from unit to unit (as seen in the voltage bins). A constant voltage source could lead to thermal runaway: as the LED heats up, V_F drops, causing current to increase, which generates more heat, further dropping V_F and increasing current until failure. Always use a constant-current driver or a circuit that actively regulates the current.

11. Practical Design and Usage Case

Case: Designing a Daytime Running Light (DRL) Module
A designer is creating a DRL module for a passenger car. The design calls for 6 LEDs to achieve the desired brightness and form factor.
1. Bin Selection: To ensure uniform appearance, the designer specifies tight color bins (e.g., 61M ± 1 step) and a single luminous flux bin (e.g., C7). They may also specify a tight forward voltage bin (e.g., 1A) to improve current sharing in a simple series configuration.
2. Thermal Design: The module will be mounted in a confined space. The designer uses a metal-core PCB (MCPCB) with a 2oz copper layer. Thermal simulation is run to ensure the solder pad temperature does not exceed 110°C in the worst-case ambient temperature (e.g., 85°C inside the headlamp assembly). According to the derating curve, at T_S=110°C, the full 1500mA is permissible, but the designer chooses to drive at 1000mA for better efficacy and longevity.
3. Electrical Design: The 6 LEDs are placed in a series string. The total forward voltage at 1000mA will be approximately 6 × 3.25V = 19.5V (typ), but could range from ~17.4V to 22.8V based on binning. A buck-boost constant-current LED driver is selected to accommodate this voltage range from a 12V automotive battery system (nominal 12V, but operating from 9V to 16V).
4. Optical Design: A secondary optic (a TIR lens) is designed over each LED to collimate the 120° emission into a controlled horizontal fan beam suitable for a DRL signature.

12. Principle Introduction

The ALFS1J-C0 is a phosphor-converted white LED. The fundamental principle involves a semiconductor chip (typically made of indium gallium nitride - InGaN) that emits blue light when forward biased (electroluminescence). This blue light is partially absorbed by a cerium-doped yttrium aluminum garnet (YAG:Ce) phosphor layer deposited over the chip. The phosphor down-converts a portion of the blue photons to longer wavelengths, primarily in the yellow region. The mixture of the remaining blue light and the converted yellow light is perceived by the human eye as white light. The exact ratio of blue to yellow, and the inclusion of other phosphors, determines the correlated color temperature (CCT) and color rendering index (CRI). The ceramic package serves as a robust substrate for mounting the chip and phosphor, and as an efficient heat spreader.

13. Development Trends

The evolution of automotive LEDs like the ALFS1J-C0 follows several clear industry trends:
1. Increased Luminous Efficacy (lm/W): Ongoing improvements in chip design, phosphor efficiency, and package thermal management aim to deliver more light output for the same electrical input power, reducing energy consumption and thermal load.
2. Higher Power Density and Miniaturization: There is a push to achieve higher flux from smaller package footprints, enabling more compact and stylized lighting designs.
3. Improved Color Consistency and Stability: Advancements in phosphor technology and binning processes lead to tighter color tolerances and reduced color shift over temperature and lifetime.
4. Enhanced Reliability and Robustness: Standards like AEC-Q102 are continuously evolving, and new tests are added to address real-world failure modes, such as sulfur resistance, which has become a key requirement.
5. Integration and Smart Lighting: The future points towards integrated modules that combine LEDs, drivers, sensors, and communication interfaces for adaptive front-lighting systems (AFS) and communication via light (Li-Fi or V2X signaling).
6. Specialized Spectra: Development of spectra optimized for specific purposes, such as improved visibility in fog or reduced glare for oncoming traffic, is an active area of research.