2820-SR3501H-AM Super Red LED Datasheet - Size 2.8x2.0mm - Voltage 2.45V - Power 0.86W - Chinese Technical Documentation

1. Product Overview

2820-SR3501H-AM serisi, zorlu otomotiv aydınlatma uygulamaları için tasarlanmış, yüksek parlaklıklı, yüzey montajlı ultra kırmızı LED'dir. Bu cihaz, katı otomotiv sınıfı güvenilirlik ve performans standartlarını karşılamak üzere tasarlanmış bir ürün ailesine aittir. Ana işlevi, araç içindeki çeşitli sinyal ve aydınlatma fonksiyonları için güvenilir, verimli ve yoğun bir kırmızı ışık kaynağı sağlamaktır.

The core advantages of this LED include compliance with the AEC-Q102 standard, ensuring its robustness in automotive environments, and a typical luminous flux output of up to 45 lumens under standard drive current. The device features a wide viewing angle of 120 degrees, making it suitable for applications requiring broad angular light distribution. It complies with RoHS, REACH, and halogen-free directives, reflecting the requirements of modern environmental and safety regulations.

The target market is specifically automotive lighting, including but not limited to interior ambient lighting, center high-mounted stop lights (CHMSL), rear combination lamps, and other signal functions where vivid red color and high reliability are critical.

2. In-depth Analysis of Technical Parameters

2.1 Luminous and Optical Characteristics

The core of luminous performance is the typical luminous flux (Φ_v) is 45 lumens. This measured value has a tolerance of ±8% and was measured with the thermal pad stabilized at 25°C. The dominant wavelength (λ_d) has a typical value of 632 nm, defining its ultra-red color point, with a specified range from 627 nm to 639 nm and a measurement tolerance of ±1 nm. The spatial light distribution is characterized by a wide viewing angle (2φ) of 120 degrees, with a tolerance of ±5 degrees. This wide beam is ideal for applications requiring good visibility from different angles.

2.2 Electrical Characteristics

Forward voltage (V_F) is a key electrical parameter, with a typical value of 2.45 V at 350 mA, ranging from 2.00 V to 2.75 V, and a measurement tolerance of ±0.05 V. The device's rated continuous forward current (I_F) can be up to 500 mA, with an absolute maximum of 1500 mA under surge conditions (pulse width ≤10 μs, duty cycle 0.005). It must be noted that this LEDis not designed for reverse operation.provides a dedicated pad pattern (package) for PCB design. This pattern is optimized for forming reliable solder joints during reflow soldering and for efficient heat transfer from the LED thermal pad to the PCB. Following this recommended layout is crucial for mechanical stability, electrical performance, and most importantly, thermal management. The pad design includes exposed thermal vias or copper pour areas to act as heat sinks.

2.3 Thermal Characteristics

Thermal management is crucial for the performance and lifespan of LEDs. The thermal resistance from junction to solder point (R_thJS) Specified by two methods: actual measurement yields a typical value of 12.8 K/W (max 16.2 K/W), electrical measurement yields a typical value of 10 K/W (max 13 K/W). Maximum allowable junction temperature (T_J) is 150°C. This device can operate and be stored within an ambient temperature range of -40°C to +125°C. Especially when operating at higher currents, proper heat dissipation is crucial to maintain the junction temperature within safe limits.

2.4 Reliability and Environmental Class

该LED满足多项关键可靠性基准。其ESD敏感度等级为2 kV（人体模型，HBM），这是汽车元件的标准。它根据汽车应用中分立光电器件的全球标准AEC-Q102修订版A进行了认证。此外，它满足硫化物测试标准A1级，表明其能抵抗腐蚀性硫环境。该元件还符合RoHS、REACH标准，且无卤素（Br<900 ppm，Cl<900 ppm，Br+Cl<1500 ppm）。其湿度敏感等级（MSL）为2级。

3. Grading System Description

To ensure color and brightness consistency in production, LEDs are sorted into different bins. The 2820-SR3501H-AM employs three independent binning criteria.

3.1 Luminous Flux Binning

LEDs are grouped based on their light output at 350 mA. The standard bin for this series is F3, with a luminous flux range of 39 lm (minimum) to 45 lm (maximum). Other available bins include F4 (45-52 lm) and F5 (52-60 lm). This allows designers to select the appropriate brightness level for their application.

3.2 Forward Voltage Binning

Binning forward voltage aids in circuit design and power supply matching. The bins include 2022 (2.00-2.25 V), 2225 (2.25-2.50 V), and 2527 (2.50-2.75 V). Understanding the V_Fbin helps in more accurately predicting power consumption and thermal load.

3.3 Dominant Wavelength Binning

Color (dominant wavelength) is strictly controlled through binning. The groups are defined as 2730 (627-630 nm), 3033 (630-633 nm), 3336 (633-636 nm), and 3639 (636-639 nm). This ensures minimal color difference between individual LEDs in the array, which is crucial for aesthetic and signaling applications.

4. Performance Curve Analysis

4.1 IV Curve and Relative Luminous Flux

The graph of forward current versus forward voltage shows a typical exponential relationship. At 350 mA, the typical V_Fis 2.45V. The curve of relative luminous flux versus forward current indicates that light output is sublinear at lower currents, becomes more linear as current increases, and tends to flatten near the maximum rated current. This highlights the importance of driving the LED at or near the recommended current for optimal efficiency.

4.2 Temperature Dependence

The performance curve clearly shows the effect of temperature. The curve of relative forward voltage versus junction temperature has a negative slope, meaning V_Fdecreases as temperature increases (typically -2 mV/°C for red LEDs). This can be used for junction temperature monitoring. The curve of relative luminous flux versus junction temperature shows that light output decreases significantly as temperature rises, a phenomenon known as thermal droop. The curve of relative wavelength versus junction temperature indicates a slight shift in dominant wavelength with temperature (typically 0.03-0.05 nm/°C for AlInGaP red LEDs), which is usually small for this material system.

4.3 Forward Current Derating and Pulse Handling Capability

The forward current derating curve is crucial for thermal design. It shows the maximum allowable continuous forward current as a function of pad temperature (T_S) function. At the maximum operating T_S125°C, the maximum I_Fis 500 mA. At higher pad temperatures, the current must be reduced to prevent exceeding the 150°C junction temperature limit. The permissible pulse handling capability diagram provides guidance for pulse operation, showing, for a given pulse width (t_FP) and the duty cycle (D) allowed peak pulse current (I_p).

4.4 Spectral Distribution

The relative spectral distribution plot confirms the monochromaticity of this ultra-red LED. The emitted light is concentrated in a narrow band around 632 nm, with almost no emission in the blue or green regions. This results in a highly saturated red color, making it ideal for automotive signal functions where color purity is specified.

5. Mechanical and Packaging Information

5.1 Physical Dimensions

LED hii inatumia ufungaji wa kifaa cha kushikilia uso (SMD) cha 2820. Jina linaonyesha ukubwa wa takriban: urefu 2.8 mm, upana 2.0 mm. Michoro halisi ya mitambo inatoa vipimo vya kina, ikiwa ni pamoja na urefu wa jumla, umbo la lenzi, na nafasi ya fremu ya waya. Isipokuwa imeelezwa vinginevyo, uvumilivu kwa kawaida ni ±0.1 mm. Ufungaji huu umeundwa kuendana na vifaa vya kukusanyika kwa kiotomatiki vya kushikilia vipande.

5.2 Recommended Land Pattern

A dedicated land pattern (footprint) is provided for PCB design. This pattern is optimized for reliable solder joint formation during reflow soldering and for effective heat transfer from the LED's thermal pad to the PCB. Adhering to this recommended layout is essential for mechanical stability, electrical performance, and most importantly, thermal management. The pad design includes exposed thermal vias or a copper pour to act as a heat sink.

5.3 Polarity Marking

The mechanical drawing in the datasheet indicates the anode and cathode terminals. Typically, there may be markings on the package, such as a notch, a dot, or a bevel, to identify the cathode. Correct polarity must be observed during assembly, as reverse connection will cause the device to malfunction and may damage it.

6. Welding and Assembly Guide

6.1 Reflow soldering temperature profile

Provides a detailed reflow soldering temperature profile to ensure reliable connections without damaging the LED. This profile specifies key parameters: preheat slope, soak time and temperature, time above liquidus (TAL), peak temperature, and cooling rate. The absolute maximum soldering temperature is 260°C for 30 seconds. Adhering to this profile is crucial to avoid thermal shock, delamination, or solder joint defects.

6.2 Precautions for use

General precautions include: avoiding mechanical stress on the lens, preventing contamination of optical surfaces, employing proper ESD handling procedures (as it is rated for 2kV HBM), and ensuring the device is stored in a dry environment according to its MSL 2 rating before use. As indicated by the derating curve, the LED should not be operated below 50 mA.

6.3 Storage Conditions

元件应储存在其原始的防潮袋中，并放入干燥剂，温度在-40°C至+125°C之间，处于非腐蚀性环境。一旦袋子打开，MSL 2等级的元件必须在特定时间范围内（通常在<30°C/60% RH下为1年）完成组装，或根据制造商的说明进行重新烘烤，以去除吸收的湿气并防止回流焊期间的“爆米花”效应。

7. Packaging and Ordering Information

7.1 Packaging Specifications

LEDs are supplied in tape and reel format, which is standard for automated SMD assembly. The packaging information details reel dimensions, carrier tape width, pocket pitch, and component orientation. This ensures compatibility with standard feeder systems on assembly lines.

7.2 Part Number System

The part number 2820-SR3501H-AM is interpreted as follows:

• 2820: Product series and package size (2.8mm x 2.0mm).
• SR: Color (Super Red).
• 350: Test current, unit milliampere (350 mA).
• 1: Lead frame type (1 = Gold-plated).
• H: Brightness grade (H = High).
• AM: Designated for automotive application grade.

This naming convention allows for precise identification of the component's key attributes.

8. Application Recommendations

8.1 Typical Application Scenarios

The main application is automotive lighting. Specific uses include:

• External SignalsRear tail lights, brake lights, high-mounted stop lamps, turn signals.
• Interior lightingInstrument cluster backlighting, switch illumination, ambient lighting, warning indicators.

Its AEC-Q102 certification and sulfur resistance make it suitable for harsh engine compartment or exterior locations, where extreme temperatures, humidity, and chemical exposure are present.

8.2 Design Considerations

Drive Circuit: It is strongly recommended to use a constant current driver instead of a constant voltage source to ensure stable light output and prevent thermal runaway. The driver design should be able to adapt to V_FGear range.

Thermal managementis the most critical aspect of the design. The PCB must provide an adequate thermal path from the LED solder pads to the heat sink or the board's ground plane. Use the provided thermal resistance (R_thJS) and derating curves to calculate the necessary thermal design to keep T_JKeep below 150°C.

Optical DesignA 120-degree viewing angle may require secondary optics (lenses, light guides) to shape the beam for specific applications, such as creating a uniform luminous appearance or a focused signal.

9. Technical Comparison and Differentiation

Compared to standard commercial-grade red LEDs, the 2820-SR3501H-AM series offers significant advantages for automotive applications:

• Reliability: AEC-Q102 certification involves rigorous stress testing (High-Temperature Operating Life, Temperature Cycling, Moisture Resistance, etc.), far exceeding commercial specifications.
• Extended Temperature RangeThe operating range of -40°C to +125°C is crucial for automotive environments, while commercial LEDs typically max out at +85°C.
• Color and Luminous Flux BinningStricter binning ensures consistency in appearance and performance of all units within vehicle lighting assemblies.
• Sulfur resistanceComplies with A1-level sulfide test standards, preventing corrosion from sulfur-containing gases present in certain automotive environments (e.g., from tires or certain seals).
• TraceabilityAutomotive-grade components typically have stricter traceability requirements throughout the supply chain.

Its primary differentiation lies in its certified robustness for the automotive ecosystem.

10. Frequently Asked Questions (FAQ)

Q: Can I drive this LED directly with a 12V car battery?
A: No. LEDs require a constant current driver. Direct connection to 12V will cause catastrophic overcurrent and immediate failure. A driver circuit (linear or switching) that regulates the current to 350 mA (or another required level within specifications) must be used.

Q: What is the purpose of the gold-plated leadframe (type "1")?
A: Gold plating provides excellent corrosion resistance and long-term superior solderability, which is crucial for long-term reliability in harsh automotive environments. It also ensures stable, low-resistance electrical connections.

Q: How to interpret the two different thermal resistance values (actual measurement vs. electrical measurement)?
A: The "actual" value (12.8 K/W) is directly measured using thermal test methods. The "electrical" value (10 K/W) is derived from the temperature-sensitive forward voltage characteristic. For conservative thermal design, it is recommended to use the higher "actual" value or the specified maximum value (16.2 K/W) in calculations.

Q: Is a heatsink always required?
A: It depends on the drive current, ambient temperature, and PCB design. At the full 500 mA current and/or high ambient temperatures, an effective thermal path (via the PCB to a heatsink or large copper area) is absolutely necessary to stay within the junction temperature limit. At lower currents and in cool environments, the PCB itself may be sufficient.

11. Practical Design Case Analysis

Scenario: Designing a Center High-Mount Stop Lamp (CHMSL) array.
The designer needs to create a CHMSL using 10 LEDs. The goals are uniform brightness and color, powered from the vehicle's 12V system, with a maximum solder joint temperature of 100°C.

Steps:

1. Electrical Design: Select a constant current driver capable of providing a total of approximately 3.5A (10 x 350mA). The driver's output voltage must be higher than the sum of the maximum V_Fin the series string. For 10 LEDs in series, V_F(max)=2.75V，驱动器需要>27.5V的输出。或者，使用带镇流电阻的并联串或单独的驱动器。
2. Thermal Design: Use derating curve, at T_S=100°C, maximum continuous I_FApproximately 520 mA, so 350 mA is safe. Calculate the required thermal impedance from junction to ambient: ΔT = T_J(max)- T_S= 150°C - 100°C = 50°C. The power P of each LED_D≈ I_F* V_F= 0.35A * 2.45V = 0.8575W. Required R_thJA≤ ΔT / P_D= 50°C / 0.8575W ≈ 58.3 K/W. Since R_thJSis approximately 12.8 K/W, the PCB and environment must provide R_thSA≤ 45.5 K/W.
3. Optical/MechanicalPlace the LED on the PCB according to the recommended pad layout. Design a light guide or diffuser to mix the light from 10 discrete sources into a single, uniform light bar as required by regulations.
4. Binning: Specify strict luminous flux (e.g., F3 or F4) and dominant wavelength (e.g., 3033) bins to ensure all 10 LEDs are tightly matched.

12. Working Principle

2820-SR3501H-AM is based on the aluminum indium gallium phosphide (AlInGaP) semiconductor material system. When a forward voltage exceeding the material's bandgap energy is applied to the p-n junction, electrons and holes are injected into the active region. Their recombination releases energy in the form of photons (light). The specific composition of the AlInGaP layer is designed to generate photons with a wavelength concentrated around 632 nm, which the human eye perceives as a saturated red color. An epoxy resin lens encapsulates the semiconductor chip, providing environmental protection and shaping the emitted light into a 120-degree viewing angle.

13. Technical Trends

The trend in automotive LED lighting (including red signal functions) is towards higher efficiency (more lumens per watt), higher power density (smaller packages, higher light output), and enhanced reliability. Simultaneously, there is a move towards integrated intelligent LED drivers (with diagnostic and communication functions, e.g., via LIN or CAN bus). Furthermore, the push for standardized, scalable lighting modules is influencing package and optical design. The 2820 package represents a mature, reliable platform, while newer designs may focus on chip-scale packaging (CSP) or integrated multi-chip modules for greater design flexibility and performance.