LED Datasheet 2820-C03501H-AM Series - Dimensions 2.8x2.0mm - Voltage 3.25V - Power 1.14W - White - English Technical Document

1. Product Overview

The 2820-C03501H-AM series is a high-brightness, surface-mount device (SMD) LED designed primarily for demanding automotive lighting applications. It is built in a compact 2820 package (2.8mm x 2.0mm footprint) and emits a cool white light. A key feature of this series is its compliance with the AEC-Q102 Rev A standard, which is the stress test qualification for discrete optoelectronic semiconductors in automotive applications. This ensures reliability under harsh automotive environmental conditions. Additional qualifications include sulfur resistance (Class A1), compliance with RoHS, REACH, and halogen-free requirements, making it suitable for modern, eco-conscious designs.

1.1 Core Advantages

• Automotive-Grade Reliability: AEC-Q102 qualification ensures performance under temperature extremes, humidity, and mechanical stress.
• High Luminous Output: Delivers a typical luminous flux of 110 lumens at a drive current of 350 mA, providing excellent brightness for its size.
• Wide Viewing Angle: A 120-degree viewing angle offers broad and uniform illumination.
• Robust Construction: Features 8 kV ESD protection (HBM) and a Moisture Sensitivity Level (MSL) of 2, enhancing handling and assembly robustness.
• Environmental Compliance: Meets RoHS, REACH, and halogen-free directives, supporting green manufacturing initiatives.

1.2 Target Market

The primary application for this LED series is automotive lighting. This includes interior lighting (dome lights, reading lights, ambient lighting), exterior signal lighting (side marker lights, rear combination lamps where high brightness is required in a small package), and potentially other illumination functions within the vehicle that require a reliable, bright white light source.

2. In-Depth Technical Parameter Analysis

2.1 Photometric and Electrical Characteristics

The key operating parameters are defined at a typical forward current (I_F) of 350 mA and a thermal pad temperature of 25°C.

• Luminous Flux (I_V): 100 lm (Min), 110 lm (Typ), 130 lm (Max). Measurement tolerance is ±8%.
• Forward Voltage (V_F): 3.00 V (Min), 3.25 V (Typ), 3.75 V (Max) at 350 mA. Measurement tolerance is ±0.05V.
• Viewing Angle (φ): 120 degrees (Typical).
• Chromaticity Coordinates (CIE): x = 0.3227 (Typ), y = 0.3351 (Typ). Tolerance for both x and y is ±0.005, placing it in the cool white region.
• Forward Current (I_F): Operating range from 50 mA to 500 mA.

2.2 Thermal Characteristics

Effective thermal management is critical for LED performance and longevity.

• Thermal Resistance (R_{th JS}): Two values are provided: a real thermal resistance (junction to solder point) of 20 K/W (Typ) to 22 K/W (Max), and an electrical thermal resistance of 16 K/W (Max). The real thermal resistance is the key parameter for calculating junction temperature in thermal design.
• Junction Temperature (T_J): The maximum allowable junction temperature is 150°C.

3. Absolute Maximum Ratings

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

• Power Dissipation (P_d): 1750 mW
• Forward Current (I_F): 500 mA (Continuous), 1000 mA (Surge, t<=10 μs, 0.5% duty cycle)
• Reverse Voltage (V_R): Not designed for reverse operation.
• Operating & Storage Temperature: -40°C to +125°C
• ESD Sensitivity (HBM): 8 kV
• Reflow Soldering Temperature: 260°C peak for 30 seconds maximum.

4. Binning System Explanation

The LEDs are sorted into bins based on key performance parameters to ensure consistency in mass production.

4.1 Luminous Flux Bins

Bins are defined by minimum and maximum luminous flux values at the test condition (I_F=350mA, 25°C thermal pad).

• J1: 100 lm to 110 lm
• J2: 110 lm to 120 lm
• J3: 120 lm to 130 lm

4.2 Forward Voltage Bins

Bins are defined by the forward voltage range at the test current.

• 3032: 3.00 V to 3.25 V
• 3235: 3.25 V to 3.50 V
• 3537: 3.50 V to 3.75 V

4.3 Color (Chromaticity) Bins

The datasheet provides a detailed chromaticity diagram with defined bins for cool white (e.g., 56M, 58M, 61M, 63M). Each bin is a quadrilateral area on the CIE 1931 chromaticity chart, defined by four sets of (x, y) coordinates. This allows selection of LEDs with very tight color consistency, which is crucial for automotive lighting where color matching across multiple LEDs is often required.

5. Performance Curve Analysis

The graphs provide essential insights into the LED's behavior under different operating conditions.

5.1 Spectral Distribution

The Relative Spectral Distribution graph shows a peak in the blue wavelength region (around 450-460nm) with a broad phosphor-converted yellow emission, resulting in a cool white light. The absence of significant output in the deep red or infrared regions is typical for white phosphor-converted LEDs.

5.2 Forward Current vs. Forward Voltage (I-V Curve)

This graph shows the exponential relationship typical of a diode. At 350 mA, the forward voltage is clustered around the typical 3.25V. Designers use this curve for driver design and power dissipation calculations.

5.3 Relative Luminous Flux vs. Forward Current

The luminous output increases sub-linearly with current. While driving at higher currents yields more light, it also generates more heat, which can reduce efficiency and lifespan. The graph helps in selecting an optimal operating point.

5.4 Temperature Dependence

• Relative Luminous Flux vs. Junction Temperature: As junction temperature (T_J) increases, luminous output decreases. This graph quantifies the drop, which is critical for thermal design to maintain consistent brightness.
• Relative Forward Voltage vs. Junction Temperature: The forward voltage has a negative temperature coefficient, decreasing as temperature rises. This can be used for indirect temperature monitoring in some applications.
• Chromaticity Shift vs. Junction Temperature & Current: These graphs show how the white point (CIE x, y coordinates) shifts with changes in drive current and junction temperature. The shifts are relatively small but must be considered in color-critical applications.

5.5 Forward Current Derating Curve

This is a crucial graph for reliable operation. It shows the maximum allowable continuous forward current as a function of 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. For example, at the maximum operating T_S of 125°C, the maximum continuous current is 500 mA.

5.6 Permissible Pulse Handling Capability

This graph defines the surge current capability for pulsed operation. It shows the permissible peak pulse current (I_F) as a function of pulse width (t_p) for different duty cycles (D). It allows the use of currents higher than the 500 mA DC maximum for short durations, which is useful for applications like strobe or flashing lights.

6. Mechanical and Packaging Information

6.1 Mechanical Dimensions

The datasheet includes a detailed dimensional drawing of the 2820 SMD package. Key dimensions include a body size of 2.8mm (length) x 2.0mm (width). The drawing specifies the location of the cathode mark, lens geometry, and pad locations. All dimensions are in millimeters with a standard tolerance of ±0.1mm unless otherwise noted.

6.2 Recommended Soldering Pad Layout

A separate drawing provides the recommended footprint for PCB design. This includes the size and spacing of the electrical pads and the central thermal pad. Adhering to this layout is essential for proper soldering, thermal performance, and mechanical stability. The thermal pad is critical for heat dissipation from the LED junction to the PCB.

7. Soldering and Assembly Guidelines

7.1 Reflow Soldering Profile

The LED is rated for a maximum peak reflow temperature of 260°C for 30 seconds. A typical reflow profile with preheat, soak, reflow, and cooling stages should be followed, ensuring the temperature does not exceed the specified limit. The Moisture Sensitivity Level (MSL) is 2, meaning the device must be used within one year of factory seal break and may require baking if exposed to ambient conditions beyond its floor life.

7.2 Precautions for Use

• ESD Protection: Although rated for 8 kV HBM, standard ESD precautions should be observed during handling and assembly.
• Cleaning: Use appropriate cleaning solvents that do not damage the LED lens or packaging material.
• Mechanical Stress: Avoid applying direct force or vibration to the LED lens.
• Current Control: Always drive the LED with a constant current source, not a constant voltage source, to ensure stable operation and prevent thermal runaway.

8. Application Suggestions and Design Considerations

8.1 Typical Application Scenarios

• Automotive Interior Lighting: Overhead console lights, map reading lights, footwell illumination, and ambient lighting strips.
• Automotive Exterior Lighting: Daytime running lights (DRLs), side marker lights, center high-mount stop lights (CHMSL), and license plate lights where high brightness in a small package is needed.

8.2 Design Considerations

• Thermal Management: This is the most critical aspect. Use the thermal resistance (R_{th JS} = 20 K/W) and the derating curve to design an adequate thermal path. This involves using a PCB with sufficient copper area (thermal vias under the thermal pad are highly recommended), and possibly an aluminum core PCB (MCPCB) for high-power or high-ambient-temperature applications.
• Driver Selection: Choose an automotive-grade LED driver capable of supplying a stable 350 mA (or other desired current) from the vehicle's electrical system (typically 12V or 24V). The driver should include protections against over-voltage, reverse polarity, and load dump transients common in automotive environments.
• Optical Design: The 120° viewing angle is suitable for diffuse illumination. For focused beams, secondary optics (lenses or reflectors) will be required. The small source size of this LED is advantageous for optical control.
• Color Consistency: For applications using multiple LEDs, specify the required color bin (e.g., 61M) to ensure uniform white color across the assembly.

9. Frequently Asked Questions (Based on Technical Parameters)

9.1 What is the typical power consumption?

At the typical operating point of 350 mA and 3.25V, the electrical power input is approximately 1.14 Watts (P = I_F * V_F = 0.35A * 3.25V).

9.2 How do I calculate the junction temperature?

The junction temperature (T_J) can be estimated using the formula: T_J = T_S + (P_d * R_{th JS}), where T_S is the measured solder pad temperature, P_d is the power dissipation (in Watts), and R_{th JS} is the real thermal resistance (20 K/W). For reliable operation, T_J must be kept below 150°C, and lower is always better for longevity.

9.3 Can I drive it with a 12V source directly?

No. Connecting it directly to a 12V source would destroy the LED instantly due to excessive current. A constant current LED driver or a current-limiting circuit is mandatory.

9.4 What does AEC-Q102 qualification mean for my design?

It means the LED component has passed a rigorous set of stress tests simulating automotive environmental conditions (extended temperature cycling, high humidity with bias, high-temperature storage, etc.). Using AEC-Q102 qualified components simplifies your system-level qualification process and significantly increases confidence in the long-term reliability of the lighting module.

10. Practical Design Case Study

Scenario: Designing an interior dome light for a passenger car. The requirement is for uniform, bright white illumination.

Design Steps:

1. LED Selection: The 2820-C03501H-AM series is chosen for its brightness, automotive grade, and compact size.
2. Quantity & Arrangement: Based on the required light level (lumens), calculate the number of LEDs needed. For example, needing 500 lumens might require 5 LEDs from the J2 bin (110-120 lm each). They would be arranged linearly or in a cluster on the PCB.
3. Thermal Design: The PCB is designed with a 2-ounce copper layer. A dedicated thermal land pattern matching the datasheet recommendation is used, with an array of thermal vias connecting it to a large copper pour on the bottom layer to act as a heat spreader. The derating curve is checked: if the cabin ambient can reach 85°C, the solder pad temperature (T_S) might be estimated at 95°C. The derating curve shows the allowable current is still above 350 mA, so the design is thermally sound.
4. Electrical Design: An automotive-qualified buck LED driver IC is selected to convert the vehicle's 12V battery voltage to a constant 350 mA output for the series string of 5 LEDs. The total forward voltage of the string is approximately 16.25V (5 * 3.25V), which is within the operating range of a typical buck converter from 12V input.
5. Optical Design: A diffuser lens or cover is placed over the LED array to blend the individual sources into a uniform area light, leveraging the 120° viewing angle of each LED.

11. Operating Principle

This LED is a phosphor-converted white LED. The core is a semiconductor chip, typically made of indium gallium nitride (InGaN), that emits blue light when forward biased (electrical current flows through it). This blue light is partially absorbed by a layer of phosphor material (e.g., yttrium aluminum garnet doped with cerium, YAG:Ce) deposited on or around the chip. The phosphor absorbs some of the blue photons and re-emits light across a broad spectrum in the yellow region. The combination of the remaining blue light and the converted yellow light is perceived by the human eye as white light. The exact shade (cool white, as in this datasheet, or warm white) is determined by the composition and thickness of the phosphor layer.

12. Technology Trends

The development of LEDs for automotive lighting follows several clear trends:

• Increased Luminous Efficacy (lm/W): Ongoing improvements in chip design, phosphor efficiency, and package thermal management lead to more light output per watt of electrical input, reducing energy consumption and thermal load.
• Higher Power Density & Miniaturization: Products like the 2820 package delivering over 100 lumens represent the trend of packing more performance into smaller footprints, enabling sleeker and more compact lighting designs.
• Enhanced Reliability and Robustness: Standards like AEC-Q102 are becoming baseline requirements. Further developments focus on improving resistance to specific automotive stressors like sulfur-containing atmospheres (addressed by the Sulfur Test Class A1 in this datasheet) and galvanic corrosion.
• Smart and Adaptive Lighting: While this is a basic component LED, the industry is moving towards integrated modules with built-in drivers, controllers, and communication interfaces (like LIN or CAN) for adaptive front-lighting systems (AFS) and dynamic interior lighting.
• Color Tuning and Quality: There is a focus on achieving higher Color Rendering Index (CRI) values and more precise color point control (tighter bins) for better aesthetic quality and safety in automotive environments.