SMD3528 Red LED Datasheet - Size 3.5x2.8mm - Voltage 2.2V - Power 0.144W - Technical Documentation

1. Product Overview\nSMD3528 is a surface-mount light-emitting diode that utilizes a single-chip red LED chip. Its compact 3.5mm x 2.8mm package size is specifically designed for applications requiring reliable, low-power red illumination. Its main advantages include a wide viewing angle of 120 degrees, consistent performance within specified temperature ranges, and compatibility with standard surface-mount technology assembly processes. The target market encompasses a wide range of consumer electronics, indicator lights, backlighting for small displays, and decorative lighting, where space and energy efficiency are critical.

2. Detailed Technical Parameters

2.1 Electrical Parameters\nElectrical characteristics define the operating boundaries and typical performance of the LED. Absolute maximum ratings, measured at a solder point temperature of 25°C, establish the limits for safe operation. The maximum continuous forward current is 30 mA, while under specific conditions (pulse width ≤10 ms, duty cycle ≤1/10), a forward pulse current of up to 40 mA is permitted. The maximum power dissipation is rated at 144 mW. The operating and storage temperature range is specified as -40°C to +80°C, with a maximum junction temperature of 125°C. For soldering, the LED can withstand a reflow profile with a peak temperature of 230°C or 260°C for a duration of 10 seconds.

Under typical operating conditions, the typical forward voltage is 2.2V, with a maximum of 2.6V. The reverse voltage rating is a minimum of 5V, and the reverse current should not exceed 10 µA.

2.2 Optical Parameters\nOptical performance is the core of LED functionality. The dominant wavelength is 625 nm, which falls within the standard red spectrum. Luminous flux output is categorized by bin, with typical values ranging from 1.5 lm to 2.5 lm at a drive current of 20 mA, depending on the bin code. The spatial distribution of light is characterized by a wide viewing angle, with a full width at half maximum of 120 degrees._s2.3 Thermal Characteristics\nThermal management is crucial for LED lifespan and performance stability. The key parameter is the junction temperature, which must not exceed 125°C. The thermal path from the LED chip to the solder point and then to the printed circuit board must be designed to ensure the junction temperature remains within safe limits during operation, especially when driven near the maximum current. The specified operating ambient temperature range of -40°C to +80°C provides guidance for the environmental conditions the device can withstand._F3. Bin System Description\nTo ensure color and brightness consistency in production, LEDs are binned according to key parameters._FP3.1 Wavelength Binning\nThe dominant wavelength is binned to control precise red hue. The provided specification lists two bins: R1 and R2. This allows designers to select LEDs with a very specific color point for their application, which is crucial for applications where color matching is critical, such as full-color displays or signage. The tolerance of wavelength measurement is built into the binning range._D3.2 Luminous Flux Binning\nThe luminous flux output is categorized to guarantee a minimum brightness level. The bins are defined by codes A3, B1, and B2, corresponding to minimum/typical values respectively. The tolerance for luminous flux measurement is ±7%. This binning allows for predictable brightness levels in LED arrays._j3.3 Forward Voltage Binning\nThe forward voltage is binned to aid circuit design, particularly for current-limiting resistor calculation and power supply design in series LED strings. The bins are C, D, E, and F, with a measurement tolerance of ±0.08V. Matching Vf bins helps ensure current distribution and brightness uniformity in parallel LED configurations.

4. Performance Curve Analysis_s4.1 IV Characteristic Curve\nThe relationship curve between forward voltage and forward current is a fundamental characteristic of any diode, including LEDs. For this SMD3528 red LED, this curve will show the typical exponential relationship of a semiconductor p-n junction. This curve is crucial for determining the operating point and designing the drive circuit. The voltage at the typical operating current of 20mA will fall within the binned Vf range._F4.2 Relative Luminous Flux vs. Forward Current\nThis curve illustrates how the light output changes with increasing drive current. For LEDs, the output typically increases linearly with current at lower levels but may exhibit saturation or reduced efficiency at higher currents due to thermal and electrical effects. This graph helps designers optimize the drive current for the desired brightness while considering efficacy and lifetime._F4.3 Temperature Dependence\nLED performance is significantly affected by temperature. A key curve shows the relative spectral energy as a function of junction temperature. For AlInGaP-based red LEDs, the light output generally decreases with increasing temperature. This curve is crucial for applications operating in varying thermal environments, providing the basis for necessary derating or thermal compensation in the drive circuit._R4.4 Spectral Distribution\nThe spectral energy distribution curve plots the emitted light intensity at different wavelengths. For a monochromatic red LED, this curve will show a single dominant peak centered around the binned wavelength. The width of this peak determines the color purity. A narrower peak indicates a more saturated and pure color._R5. Mechanical and Packaging Information

5.1 Dimensions and Outline Drawing\nThe LED package conforms to the industry-standard 3528 package size, with a nominal length of 3.5mm and a width of 2.8mm. The precise dimensional drawing provides key measurements, including package height, lens size, and lead pitch. Tolerances are specified: dimensions marked as .X have a tolerance of ±0.10mm, while .XX dimensions have a stricter tolerance of ±0.05mm.

5.2 Recommended Pad Layout and Stencil Design\nRecommended pad layouts for PCB design are provided to ensure proper soldering and mechanical stability. This includes the dimensions, shape, and spacing of the copper pads. Corresponding stencil designs are also recommended to control the amount of solder paste deposited during assembly, which is crucial for achieving reliable solder joints without causing shorts or tombstoning._d5.3 Polarity Identification\nThe cathode is typically identified by a visual marker on the LED package, such as a green dot, a notch, or a cut corner. The datasheet should clearly indicate this marking scheme. Care must be taken to place the device on the PCB with the correct polarity to ensure proper device operation._{6. Soldering and Assembly Guide}6.1 Reflow Soldering Parameters\nThis component is suitable for infrared or convection reflow soldering processes. The maximum allowable soldering temperature measured at the LED pins is specified as 230°C or 260°C, for a maximum duration of 10 seconds. Standard lead-free reflow profiles should be followed, ensuring that the peak temperature and time above liquidus do not exceed the LED's ratings.

6.2 Handling and Storage Precautions\nLEDs are sensitive to electrostatic discharge. They should be handled in an anti-static environment, using grounded wrist straps and conductive work surfaces. Devices should be stored in their original moisture barrier bags with desiccant, under conditions not exceeding the specified storage temperature range, and at low humidity to prevent moisture absorption, which can cause "popcorn" phenomenon during reflow soldering.

6.3 Cleaning\nIf cleaning is required after soldering, use approved solvents compatible with the LED epoxy lens and plastic package. Avoid ultrasonic cleaning, as high-frequency vibrations may damage internal bond wires or die attach. Always verify chemical compatibility before proceeding with any cleaning process._j7. Packaging and Ordering Information

7.1 Tape and Reel Packaging\nSMD3528 LEDs are supplied in standard embossed carrier tape on reels, suitable for automatic placement machines. The carrier tape dimensions are clearly specified to ensure compatibility with feeders. The cover tape peel strength is defined as 0.1 to 0.7 Newtons when peeled at a 10-degree angle, ensuring it remains secure during transportation yet is easy for machines to remove.

7.2 Part Numbering System\nThe product part number follows a structured naming rule: T [Shape Code] [Chip Count] [Lens Code] [Internal Code] - [Luminous Flux Code] [Color Code]. For example, T3200SRA decodes to: Shape 32, Chip Count S, Lens Code 00, Internal Code, Luminous Flux Code, and Color A. Other color codes include Y, B, G, etc. This system allows for precise identification of all key attributes.

8. Application Suggestions

8.1 Typical Application Scenarios\nSMD3528 red LEDs are highly suitable for a variety of applications: status and indicator lights on consumer electronics, backlighting for small LCD displays, keyboards, or panels, decorative and accent lighting for appliances, automotive interiors, or architectural features, as well as signal lights and emergency lighting requiring a specific red signal.

8.2 Design Considerations\nCurrent Limiting: Always use a series current-limiting resistor or constant current driver. Calculate the resistor value using the formula R = (Supply Voltage - Vf) / If. Use the maximum Vf value from the binning to ensure current does not exceed limits even on LEDs with low Vf.\nThermal Management: For continuous operation at high current or high ambient temperatures, ensure sufficient PCB copper area or heat sinking to dissipate heat and maintain a low junction temperature.\nOptical Design: When designing light guides, lenses, or diffusers, consider the 120-degree viewing angle to achieve the desired illumination pattern.

9. Technical Comparison\nCompared to through-hole red LEDs, the SMD3528 offers significant advantages for modern electronics: a smaller footprint, a thinner profile suitable for slim devices, compatibility with high-speed automated assembly, and typically better thermal performance due to direct soldering to the PCB. Within the SMD red LED series, the 3528 package is a common and cost-effective choice. Compared to newer, higher-efficacy LED packages, the 3528 may have slightly lower luminous efficacy, but it remains highly competitive in standard brightness applications due to its wide availability and proven reliability.

10. Frequently Asked Questions (FAQ)

Q: What is the difference between luminous flux grades A3, B1, and B2? A: These grades represent different minimum and typical brightness levels at 20mA. A3 is the lowest, B1 is medium, and B2 is the highest. The choice depends on the brightness required by the application._FQ: Can I drive this LED continuously at 30mA? A: Yes, 30mA is the absolute maximum continuous forward current rating. However, for optimal lifespan and reliability, it is generally recommended to operate below the maximum, such as at 20-25mA, unless the application requires maximum brightness and the thermal design is sufficiently robust.

Q: How to identify the cathode on the LED? A: The outline drawing in the datasheet should indicate the polarity marking. Typically, for the 3528 package, the cathode is marked by a green dot or a small notch/chamfer on one corner of the plastic body.

Q: Does this LED use a lens? A: According to the model decoding and the lens code "00" in the naming rules, this specific model does not have an attached primary lens. Other models with a lens code of "01" include a lens for beam shaping.

11. Practical Application Case Scenario: Designing a status indicator panel for a network switch. The panel requires ten red LEDs to indicate port activity/link status. The designer selected SMD3528 LEDs binned as R2 and B1. A 3.3V power rail is available on the PCB. Using the maximum Vf and a 20mA target current, the current-limiting resistor is calculated: R = (3.3V - 2.6V) / 0.020A = 35 ohms. A standard 33-ohm resistor is chosen, resulting in a slightly higher current of approximately 21.2mA, which is within the safe operating area. The LEDs are placed on the PCB following the recommended pad layout. Simple microcontroller GPIO pins configured as open-drain outputs, pulled up to 3.3V, can sink current to illuminate each LED. The 120-degree wide viewing angle ensures status visibility from all angles._F12. Working Principle A light-emitting diode is a semiconductor device that converts electrical energy directly into light through a process called electroluminescence. The core of a red LED like the SMD3528 is a chip made from aluminum indium gallium phosphide material. When a forward voltage is applied across the p-n junction of this semiconductor, electrons from the n-type region and holes from the p-type region are injected into the junction area. When these charge carriers recombine, they release energy in the form of photons. The specific wavelength of the emitted light is determined by the bandgap energy of the semiconductor material. The bandgap of AlInGaP corresponds to photons in the red to yellow-orange range of the visible spectrum. The epoxy encapsulation protects the chip from environmental factors and often acts as a lens to shape the light output._F13. Reliability Testing Standards The datasheet references several industry standard tests to verify LED reliability under various stress conditions. These tests simulate years of operation or harsh environments within an accelerated timeframe._F13.1 Life Test\n室温工作寿命测试：LED在室温下以最大电流运行1008小时。失效标准包括Vf偏移>200mV、光通量下降>25%、漏电流>10µA或灾难性故障。\n高温工作寿命测试：类似于RTOL，但在85°C环境温度下进行，加速热老化。\n低温工作寿命测试：在-40°C下进行，测试极端寒冷下的性能。

13.2 Gwajin Ƙarfafawar Yanayi\nGwajin Rayuwar Aiki mai Zafi da Danshi: Ana yin gwaji na sa'o'i 1008 a 60°C/90% RH tare da ƙararrawar karkata, don kimanta juriyar lalacewa ta hanyar danshi.\nGwajin Zagayawar Yanayin Zafi da Danshi: Ana sa LED ya zagaya tsakanin -20°C, 0°C, 25°C da 60°C, tare da danshin kashi 60%, ana yin zagaye 20.\nGwajin Ƙarfafawar Zafi: Ana yin saurin zagaye 100 tsakanin -40°C da 125°C. Bayan gwajin, dole ne LED ya ci gaba da aiki da kyau.

14. Ci gaban Abubuwan da ke faruwa\nMasana'antar LED na ci gaba da zuwa ga ingantacciyar inganci, ƙaramin girma da ingantaccen aminci. Ga kayan shiryawa kamar SMD3528, abubuwan da ke faruwa sun haɗa da:\nHaɓaka ingancin haske: Ci gaba da inganta ƙirar guntu, girma na waje da fasahar phosphor, suna sa sabon tsarin samfura na girman iri ɗaya su samar da ƙarin haske a kowace wutar lantarki.\nƘarfafa daidaiton launi: Matsakaicin ƙa'idodin tsayin raƙuman ruwa, ƙarfin haske da Vf suna zama ma'auni, wanda buƙatun nuni da haske masu inganci ke motsawa.\nInganta aikin zafi: Ci gaban kayan shiryawa da fasahar haɗa guntu suna taimakawa rage juriyar zafi, suna ba da damar ƙarin ƙarfin kuzari ko inganta rayuwa.\nƘananan girma: Ko da yake 3528 har yanzu yana shahara, ana ci gaba da ƙirƙirar ƙananan kayan shiryawa, ko da yake yawanci ana yin ciniki a cikin fitar da haske da sarrafa zafi.\nHaɗa kai mai hikima: Ƙarin abubuwan da ke faruwa sun haɗa da haɗa da'irar sarrafawa, na'urori masu auna firikwensin ko guntu launi da yawa a cikin kayan shiryawa guda ɗaya, wanda ya wuce sauƙaƙan fitilun da ke keɓance.

2. Detailed Technical Parameters

2.1 Electrical Parameters\nElectrical characteristics define the operating boundaries and typical performance of the LED. Absolute maximum ratings, measured at a solder point temperature of 25°C, establish the limits for safe operation. The maximum continuous forward current is 30 mA, while under specific conditions (pulse width ≤10 ms, duty cycle ≤1/10), a forward pulse current of up to 40 mA is permitted. The maximum power dissipation is rated at 144 mW. The operating and storage temperature range is specified as -40°C to +80°C, with a maximum junction temperature of 125°C. For soldering, the LED can withstand a reflow profile with a peak temperature of 230°C or 260°C for a duration of 10 seconds.

Under typical operating conditions, the typical forward voltage is 2.2V, with a maximum of 2.6V. The reverse voltage rating is a minimum of 5V, and the reverse current should not exceed 10 µA.

2.2 Optical Parameters\nOptical performance is the core of LED functionality. The dominant wavelength is 625 nm, which falls within the standard red spectrum. Luminous flux output is categorized by bin, with typical values ranging from 1.5 lm to 2.5 lm at a drive current of 20 mA, depending on the bin code. The spatial distribution of light is characterized by a wide viewing angle, with a full width at half maximum of 120 degrees.

2.3 Thermal Characteristics\nThermal management is crucial for LED lifespan and performance stability. The key parameter is the junction temperature, which must not exceed 125°C. The thermal path from the LED chip to the solder point and then to the printed circuit board must be designed to ensure the junction temperature remains within safe limits during operation, especially when driven near the maximum current. The specified operating ambient temperature range of -40°C to +80°C provides guidance for the environmental conditions the device can withstand.

3. Bin System Description\nTo ensure color and brightness consistency in production, LEDs are binned according to key parameters.

3.1 Wavelength Binning\nThe dominant wavelength is binned to control precise red hue. The provided specification lists two bins: R1 and R2. This allows designers to select LEDs with a very specific color point for their application, which is crucial for applications where color matching is critical, such as full-color displays or signage. The tolerance of wavelength measurement is built into the binning range.

3.2 Luminous Flux Binning\nThe luminous flux output is categorized to guarantee a minimum brightness level. The bins are defined by codes A3, B1, and B2, corresponding to minimum/typical values respectively. The tolerance for luminous flux measurement is ±7%. This binning allows for predictable brightness levels in LED arrays.

3.3 Forward Voltage Binning\nThe forward voltage is binned to aid circuit design, particularly for current-limiting resistor calculation and power supply design in series LED strings. The bins are C, D, E, and F, with a measurement tolerance of ±0.08V. Matching Vf bins helps ensure current distribution and brightness uniformity in parallel LED configurations.

4. Performance Curve Analysis

4.1 IV Characteristic Curve\nThe relationship curve between forward voltage and forward current is a fundamental characteristic of any diode, including LEDs. For this SMD3528 red LED, this curve will show the typical exponential relationship of a semiconductor p-n junction. This curve is crucial for determining the operating point and designing the drive circuit. The voltage at the typical operating current of 20mA will fall within the binned Vf range.

4.2 Relative Luminous Flux vs. Forward Current\nThis curve illustrates how the light output changes with increasing drive current. For LEDs, the output typically increases linearly with current at lower levels but may exhibit saturation or reduced efficiency at higher currents due to thermal and electrical effects. This graph helps designers optimize the drive current for the desired brightness while considering efficacy and lifetime.

4.3 Temperature Dependence\nLED performance is significantly affected by temperature. A key curve shows the relative spectral energy as a function of junction temperature. For AlInGaP-based red LEDs, the light output generally decreases with increasing temperature. This curve is crucial for applications operating in varying thermal environments, providing the basis for necessary derating or thermal compensation in the drive circuit.

4.4 Spectral Distribution\nThe spectral energy distribution curve plots the emitted light intensity at different wavelengths. For a monochromatic red LED, this curve will show a single dominant peak centered around the binned wavelength. The width of this peak determines the color purity. A narrower peak indicates a more saturated and pure color.

5. Mechanical and Packaging Information

5.1 Dimensions and Outline Drawing\nThe LED package conforms to the industry-standard 3528 package size, with a nominal length of 3.5mm and a width of 2.8mm. The precise dimensional drawing provides key measurements, including package height, lens size, and lead pitch. Tolerances are specified: dimensions marked as .X have a tolerance of ±0.10mm, while .XX dimensions have a stricter tolerance of ±0.05mm.

5.2 Recommended Pad Layout and Stencil Design\nRecommended pad layouts for PCB design are provided to ensure proper soldering and mechanical stability. This includes the dimensions, shape, and spacing of the copper pads. Corresponding stencil designs are also recommended to control the amount of solder paste deposited during assembly, which is crucial for achieving reliable solder joints without causing shorts or tombstoning.

5.3 Polarity Identification\nThe cathode is typically identified by a visual marker on the LED package, such as a green dot, a notch, or a cut corner. The datasheet should clearly indicate this marking scheme. Care must be taken to place the device on the PCB with the correct polarity to ensure proper device operation.

6. Soldering and Assembly Guide

6.1 Reflow Soldering Parameters\nThis component is suitable for infrared or convection reflow soldering processes. The maximum allowable soldering temperature measured at the LED pins is specified as 230°C or 260°C, for a maximum duration of 10 seconds. Standard lead-free reflow profiles should be followed, ensuring that the peak temperature and time above liquidus do not exceed the LED's ratings.

6.2 Handling and Storage Precautions\nLEDs are sensitive to electrostatic discharge. They should be handled in an anti-static environment, using grounded wrist straps and conductive work surfaces. Devices should be stored in their original moisture barrier bags with desiccant, under conditions not exceeding the specified storage temperature range, and at low humidity to prevent moisture absorption, which can cause "popcorn" phenomenon during reflow soldering.

6.3 Cleaning\nIf cleaning is required after soldering, use approved solvents compatible with the LED epoxy lens and plastic package. Avoid ultrasonic cleaning, as high-frequency vibrations may damage internal bond wires or die attach. Always verify chemical compatibility before proceeding with any cleaning process.

7. Packaging and Ordering Information

7.1 Tape and Reel Packaging\nSMD3528 LEDs are supplied in standard embossed carrier tape on reels, suitable for automatic placement machines. The carrier tape dimensions are clearly specified to ensure compatibility with feeders. The cover tape peel strength is defined as 0.1 to 0.7 Newtons when peeled at a 10-degree angle, ensuring it remains secure during transportation yet is easy for machines to remove.

7.2 Part Numbering System\nThe product part number follows a structured naming rule: T [Shape Code] [Chip Count] [Lens Code] [Internal Code] - [Luminous Flux Code] [Color Code]. For example, T3200SRA decodes to: Shape 32, Chip Count S, Lens Code 00, Internal Code, Luminous Flux Code, and Color A. Other color codes include Y, B, G, etc. This system allows for precise identification of all key attributes.

8. Application Suggestions

8.1 Typical Application Scenarios\nSMD3528 red LEDs are highly suitable for a variety of applications: status and indicator lights on consumer electronics, backlighting for small LCD displays, keyboards, or panels, decorative and accent lighting for appliances, automotive interiors, or architectural features, as well as signal lights and emergency lighting requiring a specific red signal.

8.2 Design Considerations\nCurrent Limiting: Always use a series current-limiting resistor or constant current driver. Calculate the resistor value using the formula R = (Supply Voltage - Vf) / If. Use the maximum Vf value from the binning to ensure current does not exceed limits even on LEDs with low Vf.\nThermal Management: For continuous operation at high current or high ambient temperatures, ensure sufficient PCB copper area or heat sinking to dissipate heat and maintain a low junction temperature.\nOptical Design: When designing light guides, lenses, or diffusers, consider the 120-degree viewing angle to achieve the desired illumination pattern.9. Technical Comparison\nCompared to through-hole red LEDs, the SMD3528 offers significant advantages for modern electronics: a smaller footprint, a thinner profile suitable for slim devices, compatibility with high-speed automated assembly, and typically better thermal performance due to direct soldering to the PCB. Within the SMD red LED series, the 3528 package is a common and cost-effective choice. Compared to newer, higher-efficacy LED packages, the 3528 may have slightly lower luminous efficacy, but it remains highly competitive in standard brightness applications due to its wide availability and proven reliability._{10. Frequently Asked Questions (FAQ)}Q: What is the difference between luminous flux grades A3, B1, and B2? A: These grades represent different minimum and typical brightness levels at 20mA. A3 is the lowest, B1 is medium, and B2 is the highest. The choice depends on the brightness required by the application._FQ: Can I drive this LED continuously at 30mA? A: Yes, 30mA is the absolute maximum continuous forward current rating. However, for optimal lifespan and reliability, it is generally recommended to operate below the maximum, such as at 20-25mA, unless the application requires maximum brightness and the thermal design is sufficiently robust._FQ: How to identify the cathode on the LED? A: The outline drawing in the datasheet should indicate the polarity marking. Typically, for the 3528 package, the cathode is marked by a green dot or a small notch/chamfer on one corner of the plastic body._FQ: Does this LED use a lens? A: According to the model decoding and the lens code "00" in the naming rules, this specific model does not have an attached primary lens. Other models with a lens code of "01" include a lens for beam shaping._F device.
11. Practical Application Case Scenario: Designing a status indicator panel for a network switch. The panel requires ten red LEDs to indicate port activity/link status. The designer selected SMD3528 LEDs binned as R2 and B1. A 3.3V power rail is available on the PCB. Using the maximum Vf and a 20mA target current, the current-limiting resistor is calculated: R = (3.3V - 2.6V) / 0.020A = 35 ohms. A standard 33-ohm resistor is chosen, resulting in a slightly higher current of approximately 21.2mA, which is within the safe operating area. The LEDs are placed on the PCB following the recommended pad layout. Simple microcontroller GPIO pins configured as open-drain outputs, pulled up to 3.3V, can sink current to illuminate each LED. The 120-degree wide viewing angle ensures status visibility from all angles.12. Working Principle A light-emitting diode is a semiconductor device that converts electrical energy directly into light through a process called electroluminescence. The core of a red LED like the SMD3528 is a chip made from aluminum indium gallium phosphide material. When a forward voltage is applied across the p-n junction of this semiconductor, electrons from the n-type region and holes from the p-type region are injected into the junction area. When these charge carriers recombine, they release energy in the form of photons. The specific wavelength of the emitted light is determined by the bandgap energy of the semiconductor material. The bandgap of AlInGaP corresponds to photons in the red to yellow-orange range of the visible spectrum. The epoxy encapsulation protects the chip from environmental factors and often acts as a lens to shape the light output.
13. Reliability Testing Standards The datasheet references several industry standard tests to verify LED reliability under various stress conditions. These tests simulate years of operation or harsh environments within an accelerated timeframe.13.1 Life Test\n室温工作寿命测试：LED在室温下以最大电流运行1008小时。失效标准包括Vf偏移>200mV、光通量下降>25%、漏电流>10µA或灾难性故障。\n高温工作寿命测试：类似于RTOL，但在85°C环境温度下进行，加速热老化。\n低温工作寿命测试：在-40°C下进行，测试极端寒冷下的性能。

13.2 Gwajin Ƙarfafawar Yanayi\nGwajin Rayuwar Aiki mai Zafi da Danshi: Ana yin gwaji na sa'o'i 1008 a 60°C/90% RH tare da ƙararrawar karkata, don kimanta juriyar lalacewa ta hanyar danshi.\nGwajin Zagayawar Yanayin Zafi da Danshi: Ana sa LED ya zagaya tsakanin -20°C, 0°C, 25°C da 60°C, tare da danshin kashi 60%, ana yin zagaye 20.\nGwajin Ƙarfafawar Zafi: Ana yin saurin zagaye 100 tsakanin -40°C da 125°C. Bayan gwajin, dole ne LED ya ci gaba da aiki da kyau.

14. Ci gaban Abubuwan da ke faruwa\nMasana'antar LED na ci gaba da zuwa ga ingantacciyar inganci, ƙaramin girma da ingantaccen aminci. Ga kayan shiryawa kamar SMD3528, abubuwan da ke faruwa sun haɗa da:\nHaɓaka ingancin haske: Ci gaba da inganta ƙirar guntu, girma na waje da fasahar phosphor, suna sa sabon tsarin samfura na girman iri ɗaya su samar da ƙarin haske a kowace wutar lantarki.\nƘarfafa daidaiton launi: Matsakaicin ƙa'idodin tsayin raƙuman ruwa, ƙarfin haske da Vf suna zama ma'auni, wanda buƙatun nuni da haske masu inganci ke motsawa.\nInganta aikin zafi: Ci gaban kayan shiryawa da fasahar haɗa guntu suna taimakawa rage juriyar zafi, suna ba da damar ƙarin ƙarfin kuzari ko inganta rayuwa.\nƘananan girma: Ko da yake 3528 har yanzu yana shahara, ana ci gaba da ƙirƙirar ƙananan kayan shiryawa, ko da yake yawanci ana yin ciniki a cikin fitar da haske da sarrafa zafi.\nHaɗa kai mai hikima: Ƙarin abubuwan da ke faruwa sun haɗa da haɗa da'irar sarrafawa, na'urori masu auna firikwensin ko guntu launi da yawa a cikin kayan shiryawa guda ɗaya, wanda ya wuce sauƙaƙan fitilun da ke keɓance.

1. Product Overview\nSMD3528 is a surface-mount light-emitting diode that utilizes a single-chip red LED chip. Its compact 3.5mm x 2.8mm package size is specifically designed for applications requiring reliable, low-power red illumination. Its main advantages include a wide viewing angle of 120 degrees, consistent performance within specified temperature ranges, and compatibility with standard surface-mount technology assembly processes. The target market encompasses a wide range of consumer electronics, indicator lights, backlighting for small displays, and decorative lighting, where space and energy efficiency are critical.

2. Detailed Technical Parameters
2.1 Electrical Parameters\nElectrical characteristics define the operating boundaries and typical performance of the LED. Absolute maximum ratings, measured at a solder point temperature of 25°C, establish the limits for safe operation. The maximum continuous forward current is 30 mA, while under specific conditions (pulse width ≤10 ms, duty cycle ≤1/10), a forward pulse current of up to 40 mA is permitted. The maximum power dissipation is rated at 144 mW. The operating and storage temperature range is specified as -40°C to +80°C, with a maximum junction temperature of 125°C. For soldering, the LED can withstand a reflow profile with a peak temperature of 230°C or 260°C for a duration of 10 seconds.

Under typical operating conditions, the typical forward voltage is 2.2V, with a maximum of 2.6V. The reverse voltage rating is a minimum of 5V, and the reverse current should not exceed 10 µA.
2.2 Optical Parameters\nOptical performance is the core of LED functionality. The dominant wavelength is 625 nm, which falls within the standard red spectrum. Luminous flux output is categorized by bin, with typical values ranging from 1.5 lm to 2.5 lm at a drive current of 20 mA, depending on the bin code. The spatial distribution of light is characterized by a wide viewing angle, with a full width at half maximum of 120 degrees.

2.3 Thermal Characteristics\nThermal management is crucial for LED lifespan and performance stability. The key parameter is the junction temperature, which must not exceed 125°C. The thermal path from the LED chip to the solder point and then to the printed circuit board must be designed to ensure the junction temperature remains within safe limits during operation, especially when driven near the maximum current. The specified operating ambient temperature range of -40°C to +80°C provides guidance for the environmental conditions the device can withstand.
3. Bin System Description\nTo ensure color and brightness consistency in production, LEDs are binned according to key parameters.

3.1 Wavelength Binning\nThe dominant wavelength is binned to control precise red hue. The provided specification lists two bins: R1 and R2. This allows designers to select LEDs with a very specific color point for their application, which is crucial for applications where color matching is critical, such as full-color displays or signage. The tolerance of wavelength measurement is built into the binning range.
3.2 Luminous Flux Binning\nThe luminous flux output is categorized to guarantee a minimum brightness level. The bins are defined by codes A3, B1, and B2, corresponding to minimum/typical values respectively. The tolerance for luminous flux measurement is ±7%. This binning allows for predictable brightness levels in LED arrays.

3.3 Forward Voltage Binning\nThe forward voltage is binned to aid circuit design, particularly for current-limiting resistor calculation and power supply design in series LED strings. The bins are C, D, E, and F, with a measurement tolerance of ±0.08V. Matching Vf bins helps ensure current distribution and brightness uniformity in parallel LED configurations.

4. Performance Curve Analysis4.1 IV Characteristic Curve\nThe relationship curve between forward voltage and forward current is a fundamental characteristic of any diode, including LEDs. For this SMD3528 red LED, this curve will show the typical exponential relationship of a semiconductor p-n junction. This curve is crucial for determining the operating point and designing the drive circuit. The voltage at the typical operating current of 20mA will fall within the binned Vf range._F4.2 Relative Luminous Flux vs. Forward Current\nThis curve illustrates how the light output changes with increasing drive current. For LEDs, the output typically increases linearly with current at lower levels but may exhibit saturation or reduced efficiency at higher currents due to thermal and electrical effects. This graph helps designers optimize the drive current for the desired brightness while considering efficacy and lifetime._F4.3 Temperature Dependence\nLED performance is significantly affected by temperature. A key curve shows the relative spectral energy as a function of junction temperature. For AlInGaP-based red LEDs, the light output generally decreases with increasing temperature. This curve is crucial for applications operating in varying thermal environments, providing the basis for necessary derating or thermal compensation in the drive circuit._F4.4 Spectral Distribution\nThe spectral energy distribution curve plots the emitted light intensity at different wavelengths. For a monochromatic red LED, this curve will show a single dominant peak centered around the binned wavelength. The width of this peak determines the color purity. A narrower peak indicates a more saturated and pure color.

5. Mechanical and Packaging Information

5.1 Dimensions and Outline Drawing\nThe LED package conforms to the industry-standard 3528 package size, with a nominal length of 3.5mm and a width of 2.8mm. The precise dimensional drawing provides key measurements, including package height, lens size, and lead pitch. Tolerances are specified: dimensions marked as .X have a tolerance of ±0.10mm, while .XX dimensions have a stricter tolerance of ±0.05mm.

5.2 Recommended Pad Layout and Stencil Design\nRecommended pad layouts for PCB design are provided to ensure proper soldering and mechanical stability. This includes the dimensions, shape, and spacing of the copper pads. Corresponding stencil designs are also recommended to control the amount of solder paste deposited during assembly, which is crucial for achieving reliable solder joints without causing shorts or tombstoning.

5.3 Polarity Identification\nThe cathode is typically identified by a visual marker on the LED package, such as a green dot, a notch, or a cut corner. The datasheet should clearly indicate this marking scheme. Care must be taken to place the device on the PCB with the correct polarity to ensure proper device operation.

6. Soldering and Assembly Guide

6.1 Reflow Soldering Parameters\nThis component is suitable for infrared or convection reflow soldering processes. The maximum allowable soldering temperature measured at the LED pins is specified as 230°C or 260°C, for a maximum duration of 10 seconds. A standard lead-free reflow profile should be followed, ensuring that the peak temperature and time above liquidus do not exceed the LED'sLEDs are operated at maximum current at room temperature for 1008 hours. Failure criteria include V_Fshift >200mV, luminous flux drop >25% (for AlInGaP red LEDs), leakage current >10µA, or catastrophic failure.
High-Temperature Operating Life (HTOL):Similar to RTOL but conducted at 85°C ambient temperature, accelerating thermal aging.
Low-Temperature Operating Life (LTOL):Conducted at -40°C to test performance under extreme cold.

.2 Environmental Stress Tests

High Temperature High Humidity Operating Life (H3TRB):Tests at 60°C/90% RH with bias applied for 1008 hours, assessing resistance to moisture-induced degradation.
Temperature Humidity Bias (THB) Cycling:Subjects LEDs to cycling between -20°C, 0°C, 25°C, and 60°C at 60% RH for 20 cycles.
Thermal Shock:Rapidly cycles between -40°C and 125°C for 100 cycles (15 min dwell,< sec transfer). Post-test, the LED must still function.

. Development Trends

The LED industry continuously evolves towards higher efficiency, smaller size, and greater reliability. For packages like the SMD3528, trends include:Increased Luminous Efficacy:Ongoing improvements in chip design, epitaxial growth, and phosphor technology (for white LEDs) allow newer generations of the same package size to produce more light per watt of electrical input.Enhanced Color Consistency:Tighter binning tolerances for wavelength, flux, and V_Fare becoming standard, driven by demand from high-end display and lighting applications.Improved Thermal Performance:Advances in package materials (e.g., high-thermal-conductivity plastics, ceramic substrates) and die-attach techniques help lower thermal resistance, allowing higher drive currents or improved lifetime.Miniaturization:While 3528 remains popular, even smaller packages like 2020, 1515, and 1010 are being developed for ultra-compact devices, though often with trade-offs in light output and thermal handling.Smart Integration:The broader trend includes integrating control circuitry, sensors, or multiple color chips (RGB) into a single package, moving beyond simple discrete emitters.