2820 Red LED Datasheet - SMD Package 2.8x2.0mm - 2.4V Typ - 70lm @ 350mA - Automotive Grade

1. Product Overview

The 2820 series represents a high-brightness, surface-mount red LED designed specifically for demanding automotive lighting applications. This component is engineered to meet stringent automotive industry standards, offering reliable performance in a compact SMD package. Its primary application is in automotive signal and interior lighting where consistent color output, high reliability, and long operational life are critical requirements.

The core advantages of this LED include its qualification according to AEC-Q102 Revision A, ensuring it meets the rigorous quality and reliability demands of the automotive sector. It is also compliant with RoHS and REACH environmental directives and is halogen-free, making it suitable for modern eco-conscious designs. The package is rated MSL 2, indicating moderate moisture sensitivity, which is standard for many SMD components.

2. Technical Parameter Deep Dive

2.1 Photometric and Electrical Characteristics

The key performance metrics are defined under a standard test condition of a forward current (I_F) of 350mA. The typical luminous flux is 70 lumens (lm), with a minimum of 60 lm and a maximum of 90 lm, subject to a measurement tolerance of ±8%. This high output is achieved with a typical forward voltage (V_F) of 2.4 volts, ranging from 2.00V to 2.75V (±0.05V tolerance). The dominant wavelength (λ_d) is typically 614 nanometers (nm), defining its red color, with a range from 612 nm to 624 nm (±1nm tolerance). The device offers a wide 120-degree viewing angle (φ), with a tolerance of ±5°, providing broad and uniform illumination.

2.2 Thermal and Absolute Maximum Ratings

Thermal management is crucial for LED longevity. The thermal resistance from the junction to the solder point (R_{th JS}) is specified through two methods: a real measurement of 12.8 K/W (typ) and an electrical method measurement of 10 K/W (typ). The absolute maximum ratings define the operational limits: a maximum power dissipation (P_d) of 1375 mW, a maximum continuous forward current (I_F) of 500 mA, and a surge current (I_FM) of 1500 mA for pulses ≤10 μs with a 0.005 duty cycle. The maximum junction temperature (T_J) is 150°C, while the operating and storage temperature range is from -40°C to +125°C, suitable for automotive environments. The device can withstand an ESD sensitivity of 2 kV (HBM, R=1.5kΩ, C=100pF) and a reflow soldering temperature of 260°C for 30 seconds.

3. Binning System Explanation

To ensure color and brightness consistency in production, LEDs are sorted into bins. This product uses a three-dimensional binning system.

3.1 Luminous Flux Bins

LEDs are categorized by their light output at 350mA:
• Bin F6: 60 lm (Min) to 70 lm (Max)
• Bin F7: 70 lm (Min) to 80 lm (Max)
• Bin F8: 80 lm (Min) to 90 lm (Max)

3.2 Forward Voltage Bins

LEDs are sorted by their electrical characteristics:
• Bin 2022: 2.00V (Min) to 2.25V (Max)
• Bin 2225: 2.25V (Min) to 2.50V (Max)
• Bin 2527: 2.50V (Min) to 2.75V (Max)

3.3 Dominant Wavelength Bins

LEDs are grouped by their precise red color point:
• Group 1215: 612 nm (Min) to 615 nm (Max)
• Group 1518: 615 nm (Min) to 618 nm (Max)
• Group 1821: 618 nm (Min) to 621 nm (Max)
• Group 2124: 621 nm (Min) to 624 nm (Max)

All binning measurements have specified tolerances: ±8% for luminous flux, ±0.05V for forward voltage, and ±1nm for dominant wavelength, using a 25ms current pulse.

4. Performance Curve Analysis

4.1 Spectral Distribution and Radiation Pattern

The relative spectral distribution graph shows a peak in the red region around 614 nm, with minimal emission in other spectral bands, confirming a pure red color. The radiation pattern diagram illustrates the typical spatial distribution of light, correlating with the 120° viewing angle specification where intensity drops to half at ±60° from the centerline.

4.2 Current-Voltage (I-V) and Current-Luminous Flux Relationships

The Forward Current vs. Forward Voltage graph exhibits the characteristic exponential curve of a diode. At the typical operating point of 350mA, the voltage is approximately 2.4V. The Relative Luminous Flux vs. Forward Current graph shows that light output increases sub-linearly with current, emphasizing the importance of constant-current drive for stable brightness.

4.3 Temperature Dependence

The Relative Forward Voltage vs. Junction Temperature graph shows a negative temperature coefficient; V_F decreases as temperature increases, which is typical for LEDs. The Relative Luminous Flux vs. Junction Temperature graph indicates that light output decreases as the junction temperature rises, highlighting the critical need for effective thermal management to maintain brightness. The Relative Wavelength Shift vs. Junction Temperature graph shows a slight shift in dominant wavelength (typically a few nanometers) with temperature, which is important for color-critical applications.

4.4 Derating and Pulse Handling

The Forward Current Derating Curve dictates the maximum allowable continuous current based on the solder pad temperature (T_S). For example, at the maximum T_S of 125°C, the maximum I_F is 500 mA. The graph also specifies a minimum operating current of 50 mA. The Permissible Pulse Handling Capability graph defines the peak pulse current (I_F) allowable for a given pulse width (t_p) and duty cycle (D) at 25°C, useful for pulsed or multiplexed driving schemes.

5. Mechanical and Package Information

5.1 Package Dimensions

The LED comes in a surface-mount device (SMD) package with the industry designation 2820, corresponding to approximate dimensions of 2.8mm in length and 2.0mm in width. The detailed mechanical drawing in the datasheet provides all critical dimensions, including overall height, lead spacing, and pad locations. All dimensions are in millimeters with a standard tolerance of ±0.1mm unless otherwise specified.

5.2 Recommended Solder Pad Layout

A dedicated land pattern diagram is provided to guide PCB design. Adhering to this recommended pad layout is essential for achieving reliable solder joints, proper thermal dissipation from the thermal pad, and correct alignment of the LED. The diagram includes dimensions for the solder mask opening and the copper pad, ensuring optimal solder fillet formation and mechanical stability.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Profile

The component is compatible with standard infrared or convection reflow soldering processes. The datasheet includes a reflow profile specifying the critical parameters: a maximum peak temperature of 260°C, which the package can withstand for up to 30 seconds. The profile details the preheat, soak, reflow, and cooling stages to prevent thermal shock and ensure reliable solder connections without damaging the LED die or package.

6.2 Precautions for Use

Key handling and usage precautions include: avoiding mechanical stress on the LED lens, preventing contamination of the optical surface, ensuring proper ESD handling procedures are followed due to the 2kV HBM rating, and respecting the moisture sensitivity level (MSL 2) by baking the components if the moisture barrier bag has been opened for longer than the specified time before reflow.

7. Packaging and Ordering Information

7.1 Part Numbering System

The part number 2820-UR3501H-AM is decoded as follows:
• 2820: Product family and package size.
• UR: Color code for Red.
• 350: Test current in milliamps (350mA).
• 1: Lead frame type (1 = Gold-plated).
• H: Brightness level (H = High).
• AM: Designates Automotive application series.

The datasheet also provides a comprehensive list of other available color codes (e.g., UB for Blue, UG for Green, UA for Amber, various white temperatures) for the 2820 platform.

7.2 Packaging Specifications

The LEDs are supplied on tape and reel for compatibility with automated pick-and-place assembly equipment. The packaging information section details the reel dimensions, tape width, pocket spacing, and orientation of the components on the tape, which is crucial for setting up assembly lines correctly.

8. Application Suggestions

8.1 Typical Application Scenarios

The primary and stated application is automotive lighting. This encompasses a wide range of uses:
• Exterior Signaling: Rear combination lamps (tail/stop lights), center high-mount stop lights (CHMSL), side marker lights.
• Interior Lighting: Dashboard backlighting, switch illumination, ambient lighting, reading lights.
• Its AEC-Q102 qualification, wide temperature range, and sulfur resistance (Class A1) make it robust for the harsh automotive environment with exposure to temperature cycles, vibration, and potential corrosive atmospheres.

8.2 Design Considerations

• Drive Circuit: Always use a constant-current driver to ensure stable light output and prevent thermal runaway. The forward voltage bin should be considered for driver design.
• Thermal Management:** The low thermal resistance (10-13 K/W) is from junction to solder point. The actual junction temperature depends heavily on the PCB's thermal design (copper area, vias, board material). Use the derating curve to design an adequate heatsinking solution via the PCB to keep T_J within safe limits, especially at high ambient temperatures.
• Optical Design: The 120° viewing angle is useful for applications requiring wide illumination. For more focused light, secondary optics (lenses) would be required.
• Sulfur Resistance: The Class A1 sulfur test criteria rating indicates a degree of resistance to sulfur-containing atmospheres, which is beneficial for applications in certain geographic regions or industrial environments, though primarily targeted at automotive.

9. Technical Comparison and Differentiation

While many SMD red LEDs exist, this 2820 series differentiates itself through its automotive-grade qualification (AEC-Q102). This is not just a marketing term; it signifies the component has passed a suite of stringent stress tests defined by the automotive industry for long-term reliability under extreme conditions. Compared to commercial-grade LEDs, this series offers guaranteed performance over the specified -40°C to +125°C range, higher surge current tolerance, and documented sulfur resistance. The combination of high luminous flux (70lm typ), a wide viewing angle, and this reliability package makes it a strong candidate for automotive designers who cannot compromise on component failure rates.

10. Frequently Asked Questions (Based on Technical Parameters)

Q: What is the recommended operating current for this LED?
A: The datasheet characterizes performance at 350mA, which is considered the typical operating point. It can be operated from 50mA to its absolute maximum of 500mA continuous current, but brightness and efficiency will vary. Always refer to the derating curve if operating at high ambient temperatures.

Q: How do I interpret the luminous flux binning (F6, F7, F8)?
A: This allows you to select the brightness grade for your application. For example, ordering from Bin F7 guarantees the LED will produce between 70 and 80 lumens when driven at 350mA under standard test conditions. This ensures consistency in the brightness of your final product.

Q: The forward voltage bin is 2225. What does this mean for my driver design?
A: It means the V_F of your LEDs will be between 2.25V and 2.50V at 350mA. Your constant-current driver must be able to provide the required current while supplying a voltage equal to or higher than the maximum V_F in the chain (considering series connections) plus any headroom for the driver itself.

Q: Is a heatsink necessary?
A> While the LED itself does not have an attached heatsink, effective thermal management is essential. The heat must be conducted away from the solder pads through the PCB. For operation at full current (350-500mA) or in high ambient temperatures, a PCB with significant thermal copper area (acting as a heatsink) is strongly recommended to maintain long-term reliability and prevent luminous flux degradation.

11. Design and Usage Case Study

Scenario: Designing a High-Brightness Automotive Stop Light.
1. Requirement: A cluster of LEDs for a stop light must meet specific photometric intensity regulations, survive automotive temperature cycles (-40°C to 85°C ambient), and have a lifespan exceeding 10,000 hours.
2. Component Selection: The 2820-UR3501H-AM is chosen for its AEC-Q102 qualification, high flux output (70lm typ), and ability to operate at 125°C junction temperature.
3. Thermal Design: The PCB is designed with a 2-ounce copper layer on the top and bottom, connected by multiple thermal vias under the LED's thermal pad. Thermal simulation is run to ensure the junction temperature remains below 110°C when the brake is applied continuously at the maximum cabin temperature.
4. Electrical Design: LEDs are arranged in a series-parallel configuration. A buck-mode constant-current LED driver IC is selected that can handle the input voltage range (9-16V) and provide a stable 350mA output, with its voltage rating exceeding the sum of the maximum V_F (Bin 2527) for the series string.
5. Result: The final assembly passes all automotive reliability tests (thermal cycling, humidity, vibration) and provides consistent, bright red light output throughout the vehicle's life.

12. Operating Principle

This device is a light-emitting diode (LED). Its operation is based on electroluminescence in a semiconductor material. When a forward voltage exceeding the diode's threshold (approximately 2.0V for this red LED) is applied, electrons and holes are injected into the active region from the n-type and p-type semiconductor layers, respectively. These charge carriers recombine, releasing energy in the form of photons (light). The specific wavelength (color) of the emitted light, in this case red around 614 nm, is determined by the bandgap energy of the semiconductor materials used in the LED chip's active region. The light is then extracted through the package's epoxy lens, which is shaped to achieve the desired 120-degree viewing angle.

13. Technology Trends

The development of LEDs for automotive lighting follows several clear trends. There is a continuous push for higher luminous efficacy (more lumens per watt) to reduce electrical load and improve energy efficiency, crucial for electric vehicles. Improved color consistency and stability over temperature and lifetime remain important, especially with the adoption of camera-based Advanced Driver Assistance Systems (ADAS) that must reliably detect signal lights. Miniaturization continues, allowing for slimmer and more stylized lamp designs. Furthermore, the integration of smart functionalities, such as adaptive lighting and communication via light (Li-Fi), is an emerging area, though it typically involves more complex packaged modules rather than discrete LEDs like the 2820. The 2820 series sits within the trend of providing robust, high-performance discrete components that serve as the reliable building blocks for these advanced lighting systems.