1. Product Overview
The Shwo series represents a line of surface-mount, high-power LED devices engineered for demanding lighting applications. Its core design philosophy combines high luminous output with a compact form factor, making it a versatile solution for a broad spectrum of illumination needs.
1.1 Core Advantages and Positioning
A key differentiator of this series is its electrically isolated thermal pad. This feature provides significant convenience for designers by decoupling thermal management from electrical layout considerations, simplifying PCB design and enhancing reliability. The series is positioned as a promising solution to meet contemporary Solid-State Lighting requirements, offering a balance of performance, size, and design flexibility.
1.2 Target Applications
The device is suitable for a wide range of lighting applications, including but not limited to: general illumination, flash lighting, spot lighting, signal lighting, and various industrial and commercial lighting fixtures. Specific use cases mentioned are decorative and entertainment lighting, orientation marker lights (e.g., for steps, exit ways), exterior and interior automotive illumination, and agriculture lighting.
2. Key Features and Compliance
- LM-80 Certified: Provides reliable lumen maintenance data for lighting design and qualification.
- High Efficiency in Small Package: Delivers significant light output from a compact SMD footprint.
- ESD Protection: Robust electrostatic discharge protection up to 8KV (HBM).
- Soldering Method: Designed for standard Surface-Mount Technology (SMT) assembly processes.
- Comprehensive Binning: Products are binned and sorted based on Brightness (Luminous Flux), Forward Voltage, Wavelength, and Chromaticity to ensure color and performance consistency.
- Moisture Sensitivity: Rated at MSL Level 1, indicating unlimited floor life at conditions ≤30°C/85% RH, which simplifies handling and storage.
- Environmental Compliance: The product is RoHS compliant, matches ANSI binning standards for white LEDs, complies with EU REACH regulations, and is Halogen Free (Br<900ppm, Cl<900ppm, Br+Cl<1500ppm).
3. Technical Parameters: In-Depth Objective Interpretation
3.1 Absolute Maximum Ratings
The device's operational limits are defined to ensure long-term reliability. The maximum DC forward current (I_F) is 700mA when the thermal pad temperature is maintained at 25°C. For pulsed operation, a peak pulse current (I_Pulse) of 1000mA is allowed under a duty cycle of 1/10 at 1kHz. The maximum junction temperature (T_J) is 125°C, and the operating temperature range for the thermal pad (T_Opr) is from -40°C to +100°C. It is critical to note that these LEDs are not designed for reverse bias operation.
3.2 Thermal Characteristics
Thermal management is paramount for high-power LEDs. The thermal resistance (R_th) varies by color: it is 10°C/W for Blue, Green, Cool-White, Neutral-White, and Warm-White LEDs, and 12°C/W for Red, Amber, and Orange LEDs. This parameter indicates how effectively heat is transferred from the LED junction to the thermal pad. A lower value signifies better thermal performance, which is directly linked to higher light output and longer lifespan.
3.3 Photometric and Electrical Characteristics
The luminous flux or radiometric power is specified at a drive current of 350mA with the thermal pad at 25°C. The datasheet provides minimum values for various part numbers across different colors. For instance, typical minimum luminous flux values range from approximately 45 lm for Amber to 530 lm for Royal Blue (measured as radiometric power in mW). Forward voltage (V_f) for the white LED variants is binned across a range from 2.65V to 3.55V.
4. Binning System Explanation
4.1 Wavelength/Color Temperature Binning
The product nomenclature includes specific codes for color. For white LEDs, this corresponds to Correlated Color Temperature (CCT) bins. The series offers a wide CCT range from 2700K (Warm White) to 6500K (Cool White), with intermediate options like 3000K, 3500K, 4000K, 4500K, 5000K, and 5700K. Each CCT is further divided into multiple MacAdam Ellipse steps (e.g., 57K-1 to 57K-4) to ensure tight color consistency. For monochromatic LEDs, bins are defined by dominant wavelength ranges (e.g., Red: 620-630nm, Blue: 460-485nm).
4.2 Luminous Flux Binning
LEDs are sorted based on their minimum luminous flux output at standard test conditions. The part number itself encodes this minimum flux value. For example, codes like 'F51', 'F61', 'F91' in the part number indicate different minimum flux tiers for a given color and drive current.
4.3 Forward Voltage Binning
Forward voltage is another critical parameter for electrical design, particularly for driving multiple LEDs in series. The white LED part numbers specify a forward voltage bin range (e.g., 2.65-3.55V). Some ordering codes further break this down into sub-bins like U4 (2.65-2.95V), V1 (2.95-3.25V), and V2 (3.25-3.55V), allowing for more precise current matching in driver design.
5. Part Number Nomenclature and Ordering
The product naming convention follows a structured format: ELSW – ABCDE – FGHIJ – V1234.
- AB: Represents the minimum luminous flux (in lm) or radiometric power (in mW).
- C: Indicates the radiation pattern (e.g., '1' for Lambertian).
- D: Denotes the color or CCT (e.g., 'C' for Cool-White, 'M' for Warm-White, 'R' for Red).
- E: Specifies power consumption (e.g., '1' for 1W).
- F, G, H, I, J: Internal and packaging type codes (e.g., 'H' indicates packaging type, with 'P' for Tape).
- V: Forward voltage bin code.
- 1234: Color bin or CCT bin code.
This system allows for precise identification and ordering of LEDs with specific optical, electrical, and thermal characteristics.
6. White LED Specifications
The datasheet provides detailed tables for standard and high-luminous white LED variants. All white LEDs conform to ANSI binning standards. Key parameters listed for each order code include the minimum luminous flux, the specific CCT bin range, the forward voltage range, and the minimum Color Rendering Index (CRI). CRI values are typically 70 for Cool White and 75 for Neutral and Warm White variants. The typical viewing angle is 120° for the standard series.
7. Mechanical, Assembly, and Handling Guidelines
7.1 Soldering and Reflow
The device is intended for SMT assembly. The maximum soldering temperature during reflow should not exceed 260°C, and a maximum of two reflow cycles is allowable. Designers must adhere to the recommended reflow profile for the specific solder paste used.
7.2 Moisture Sensitivity and Storage
With an MSL Level 1 rating, the components have unlimited floor life under standard factory conditions (≤30°C/85% RH). This eliminates the need for baking prior to use under normal circumstances, simplifying inventory management. The storage temperature range is -40°C to +100°C.
8. Application Suggestions and Design Considerations
8.1 Thermal Design
The electrically isolated thermal pad is a significant advantage. Designers must ensure an adequate thermal path from the pad to the PCB's heat sink, using sufficient thermal vias and copper area. Proper heat sinking is essential to maintain the junction temperature below 125°C to ensure rated luminous output and longevity. The different thermal resistances for various colors should be factored into the thermal model.
8.2 Electrical Design
A constant current driver is recommended for optimal performance and stability. The forward voltage binning information should be used to calculate the appropriate driver voltage, especially when connecting multiple LEDs in series. The 8KV ESD protection is robust but standard ESD handling precautions during assembly are still advised.
8.3 Optical Design
The Lambertian radiation pattern (for most variants) provides a wide, uniform light distribution. For applications requiring secondary optics, this pattern is generally well-suited. Designers should account for the minimum luminous flux values in their system's photometric calculations.
9. Common Questions Based on Technical Parameters
Q: What is the actual power consumption of the \"1W\" LED?
A: The \"1W\" designation typically refers to a common drive condition, often around 350mA. The actual power consumed is the product of the forward voltage (V_f) and the drive current (I_f). For example, at 350mA and a V_f of 3.2V, the power is approximately 1.12W.
Q: How does thermal pad temperature affect light output?
A> Light output decreases as junction temperature increases. The datasheet specifies flux at T_pad=25°C. In real applications, effective cooling is necessary to minimize temperature rise and maintain high efficiency and consistent color.
Q: Can I drive this LED at currents higher than 350mA?
A> The Absolute Maximum Rating for DC current is 700mA. While operation up to this current is possible, it will generate significantly more heat, require more robust thermal management, and may affect lifetime and color stability. The performance data (luminous flux) is provided at 350mA.
10. Practical Use Case Example
Consider designing a high-quality downlight for residential use requiring warm white light (3000K) with good color rendering (CRI >75). A designer would select a part number like ELSW-F71M1-0LPGS-C3000 from the datasheet. This specifies a minimum flux of 70 lm at 350mA, a CCT of 3000K (within bins 30K-1 to 30K-4), a forward voltage between 2.65V and 3.55V, and a minimum CRI of 75. The designer would then:
- Design a PCB with a sufficient copper pad and thermal vias under the LED's thermal pad to dissipate heat.
- Select a constant-current driver capable of delivering 350mA with a voltage compliance that accommodates the V_f range of multiple LEDs if used in series.
- Incorporate appropriate optics (e.g., a secondary lens or reflector) to achieve the desired beam angle for the downlight.
- Use the minimum flux value of 70 lm in the system's total lumen calculation to ensure the final fixture meets its photometric targets.
11. Operating Principle Introduction
Light Emitting Diodes (LEDs) are semiconductor devices that emit light when an electric current passes through them. This phenomenon, called electroluminescence, occurs as electrons recombine with electron holes within the device, releasing energy in the form of photons. The specific wavelength (color) of the light is determined by the energy band gap of the semiconductor materials used. White LEDs are typically created by using a blue or ultraviolet LED chip coated with a phosphor material. The phosphor absorbs a portion of the chip's light and re-emits it at longer wavelengths (yellow, red), mixing with the remaining blue light to produce white light. The correlated color temperature (CCT) and Color Rendering Index (CRI) are controlled by the composition and thickness of the phosphor layer.
12. Industry Trends and Context
The Shwo series, with its SMD format, high power, and isolated thermal pad, aligns with several key trends in solid-state lighting. The industry continues to drive towards higher efficacy (lumens per watt), improved reliability, and greater design integration. SMD packages enable automated, high-volume assembly, reducing manufacturing costs. The move towards standardized binning (like ANSI) facilitates consistency and interchangeability in lighting products. Furthermore, features like LM-80 certification and halogen-free compliance address growing market demands for longevity, sustainability, and environmental responsibility. The device's suitability for diverse applications, from general lighting to automotive and agriculture, reflects the expanding role of LEDs beyond simple illumination into areas like human-centric lighting, communication (Li-Fi), and plant growth stimulation.
LED Specification Terminology
Complete explanation of LED technical terms
Photoelectric Performance
| Term | Unit/Representation | Simple Explanation | Why Important |
|---|---|---|---|
| Luminous Efficacy | lm/W (lumens per watt) | Light output per watt of electricity, higher means more energy efficient. | Directly determines energy efficiency grade and electricity cost. |
| Luminous Flux | lm (lumens) | Total light emitted by source, commonly called "brightness". | Determines if the light is bright enough. |
| Viewing Angle | ° (degrees), e.g., 120° | Angle where light intensity drops to half, determines beam width. | Affects illumination range and uniformity. |
| CCT (Color Temperature) | K (Kelvin), e.g., 2700K/6500K | Warmth/coolness of light, lower values yellowish/warm, higher whitish/cool. | Determines lighting atmosphere and suitable scenarios. |
| CRI / Ra | Unitless, 0–100 | Ability to render object colors accurately, Ra≥80 is good. | Affects color authenticity, used in high-demand places like malls, museums. |
| SDCM | MacAdam ellipse steps, e.g., "5-step" | Color consistency metric, smaller steps mean more consistent color. | Ensures uniform color across same batch of LEDs. |
| Dominant Wavelength | nm (nanometers), e.g., 620nm (red) | Wavelength corresponding to color of colored LEDs. | Determines hue of red, yellow, green monochrome LEDs. |
| Spectral Distribution | Wavelength vs intensity curve | Shows intensity distribution across wavelengths. | Affects color rendering and quality. |
Electrical Parameters
| Term | Symbol | Simple Explanation | Design Considerations |
|---|---|---|---|
| Forward Voltage | Vf | Minimum voltage to turn on LED, like "starting threshold". | Driver voltage must be ≥Vf, voltages add up for series LEDs. |
| Forward Current | If | Current value for normal LED operation. | Usually constant current drive, current determines brightness & lifespan. |
| Max Pulse Current | Ifp | Peak current tolerable for short periods, used for dimming or flashing. | Pulse width & duty cycle must be strictly controlled to avoid damage. |
| Reverse Voltage | Vr | Max reverse voltage LED can withstand, beyond may cause breakdown. | Circuit must prevent reverse connection or voltage spikes. |
| Thermal Resistance | Rth (°C/W) | Resistance to heat transfer from chip to solder, lower is better. | High thermal resistance requires stronger heat dissipation. |
| ESD Immunity | V (HBM), e.g., 1000V | Ability to withstand electrostatic discharge, higher means less vulnerable. | Anti-static measures needed in production, especially for sensitive LEDs. |
Thermal Management & Reliability
| Term | Key Metric | Simple Explanation | Impact |
|---|---|---|---|
| Junction Temperature | Tj (°C) | Actual operating temperature inside LED chip. | Every 10°C reduction may double lifespan; too high causes light decay, color shift. |
| Lumen Depreciation | L70 / L80 (hours) | Time for brightness to drop to 70% or 80% of initial. | Directly defines LED "service life". |
| Lumen Maintenance | % (e.g., 70%) | Percentage of brightness retained after time. | Indicates brightness retention over long-term use. |
| Color Shift | Δu′v′ or MacAdam ellipse | Degree of color change during use. | Affects color consistency in lighting scenes. |
| Thermal Aging | Material degradation | Deterioration due to long-term high temperature. | May cause brightness drop, color change, or open-circuit failure. |
Packaging & Materials
| Term | Common Types | Simple Explanation | Features & Applications |
|---|---|---|---|
| Package Type | EMC, PPA, Ceramic | Housing material protecting chip, providing optical/thermal interface. | EMC: good heat resistance, low cost; Ceramic: better heat dissipation, longer life. |
| Chip Structure | Front, Flip Chip | Chip electrode arrangement. | Flip chip: better heat dissipation, higher efficacy, for high-power. |
| Phosphor Coating | YAG, Silicate, Nitride | Covers blue chip, converts some to yellow/red, mixes to white. | Different phosphors affect efficacy, CCT, and CRI. |
| Lens/Optics | Flat, Microlens, TIR | Optical structure on surface controlling light distribution. | Determines viewing angle and light distribution curve. |
Quality Control & Binning
| Term | Binning Content | Simple Explanation | Purpose |
|---|---|---|---|
| Luminous Flux Bin | Code e.g., 2G, 2H | Grouped by brightness, each group has min/max lumen values. | Ensures uniform brightness in same batch. |
| Voltage Bin | Code e.g., 6W, 6X | Grouped by forward voltage range. | Facilitates driver matching, improves system efficiency. |
| Color Bin | 5-step MacAdam ellipse | Grouped by color coordinates, ensuring tight range. | Guarantees color consistency, avoids uneven color within fixture. |
| CCT Bin | 2700K, 3000K etc. | Grouped by CCT, each has corresponding coordinate range. | Meets different scene CCT requirements. |
Testing & Certification
| Term | Standard/Test | Simple Explanation | Significance |
|---|---|---|---|
| LM-80 | Lumen maintenance test | Long-term lighting at constant temperature, recording brightness decay. | Used to estimate LED life (with TM-21). |
| TM-21 | Life estimation standard | Estimates life under actual conditions based on LM-80 data. | Provides scientific life prediction. |
| IESNA | Illuminating Engineering Society | Covers optical, electrical, thermal test methods. | Industry-recognized test basis. |
| RoHS / REACH | Environmental certification | Ensures no harmful substances (lead, mercury). | Market access requirement internationally. |
| ENERGY STAR / DLC | Energy efficiency certification | Energy efficiency and performance certification for lighting. | Used in government procurement, subsidy programs, enhances competitiveness. |