1. Product Overview
The UVC3535CZ0315 series represents a high-reliability, ceramic-based LED solution engineered specifically for demanding ultraviolet (UVC) applications. This product is designed to deliver consistent performance in environments where germicidal efficacy is paramount. Its core advantage lies in the robust ceramic package, which offers superior thermal management compared to traditional plastic packages, directly contributing to longer operational lifespan and stable output. The primary target market includes manufacturers of professional and consumer-grade disinfection devices, water purification systems, and air sterilization units where reliable UVC emission is critical.
2. Technical Parameter Deep-Dive
2.1 Photometric and Electrical Characteristics
The LED operates at a forward current (IF) of 300mA. The forward voltage (VF) has a specified range of 5.0V to 8.0V, which is a critical parameter for driver design to ensure proper current regulation. The radiant flux, the measure of total optical power output, is specified with a minimum of 20mW, typical of 25mW, and maximum of 30mW under standard test conditions. The peak wavelength is centered in the 270nm to 285nm range, which is within the most effective band for disrupting the DNA/RNA of microorganisms.
2.2 Absolute Maximum Ratings and Thermal Properties
Adherence to Absolute Maximum Ratings is essential for device longevity. The maximum permissible DC forward current is 300mA. The device can withstand Electrostatic Discharge (ESD) up to 2000V (Human Body Model), which is a significant reliability feature for handling and assembly. The maximum junction temperature (TJ) is rated at 90°C. The thermal resistance from junction to solder point (Rth) is 20°C/W. This value is crucial for heatsink design; for example, at the full 300mA drive current, the power dissipation could be up to 2.4W (8.0V * 0.3A), potentially raising the junction temperature by 48°C above the solder point temperature. Therefore, maintaining a low solder point temperature is vital to keep TJ within safe limits.
The operating temperature range is from -40°C to +85°C, and the storage temperature range is from -40°C to +100°C, indicating suitability for a wide variety of environmental conditions.
3. Binning System Explanation
The product is classified into bins to ensure consistency in application. Understanding these bins is key for design and procurement.
3.1 Radiant Flux Binning
Radiant flux is binned into two categories: Q4 (20-25mW) and Q5 (25-30mW). Designers must select the appropriate bin based on the required irradiance dose for their application.
3.2 Peak Wavelength Binning
The peak wavelength is tightly controlled and binned as follows: U27A (270-275nm), U27B (275-280nm), and U28 (280-285nm). The germicidal effectiveness can vary slightly across this range, so bin selection may be important for optimized system performance.
3.3 Forward Voltage Binning
Forward voltage is binned in 0.5V increments from 5.0V to 8.0V (e.g., 5055 for 5.0-5.5V, 5560 for 5.5-6.0V, etc.). This is primarily for driver efficiency considerations and to group LEDs with similar electrical characteristics when used in arrays.
4. Performance Curve Analysis
4.1 Spectrum and Relative Radiant Flux vs. Current
The spectrum curve shows a narrow emission peak centered around the specified wavelength (e.g., 270-285nm), with minimal sideband emission, confirming its purity as a UVC source. The Relative Radiant Flux vs. Forward Current curve is nearly linear up to the rated 300mA, indicating good efficiency and predictable output scaling with current.
4.2 Forward Current vs. Forward Voltage & Peak Wavelength vs. Current
The I-V curve exhibits the typical exponential characteristic of a diode. The forward voltage increases with current, which must be accounted for in constant-current driver design. The Peak Wavelength vs. Current curve shows minimal shift (typically only a few nanometers) over the operating current range, indicating stable spectral performance.
4.3 Thermal Derating and Relative Radiant Flux vs. Temperature
The Relative Radiant Flux vs. Ambient Temperature curve demonstrates the negative temperature coefficient of LED output. Radiant flux decreases as ambient (and thus junction) temperature rises. The Derating Curve graphically defines the maximum allowable forward current as a function of ambient temperature. To prevent exceeding TJ(max), the drive current must be reduced when operating at high ambient temperatures. For instance, at an ambient temperature of 85°C, the maximum allowed current is significantly lower than 300mA.
5. Mechanical and Package Information
5.1 Dimensions and Pad Configuration
The package dimensions are 3.5mm (L) x 3.5mm (W) x 0.99mm (H), with a tolerance of ±0.2mm. The pad configuration is clearly defined: Pad 1 is the Anode (+), Pad 2 is the Cathode (-), and Pad 3 is a dedicated Thermal Pad. The thermal pad is essential for efficient heat transfer from the LED die to the printed circuit board (PCB). The PCB layout must have a corresponding thermally conductive pad connected to a ground plane or heatsink to maximize heat dissipation.
6. Soldering and Assembly Guidelines
The device is suitable for Surface-Mount Technology (SMT) processes. Reflow soldering should not be performed more than twice to avoid thermal stress on the ceramic package and internal bonds. During the reflow process, mechanical stress on the LED body must be avoided. After soldering, the PCB should not be bent, as this can crack the ceramic package or solder joints. Standard lead-free reflow profiles are applicable, but the peak temperature and time above liquidus must be controlled according to the ceramic package's specifications (refer to general IPC/JEDEC guidelines for ceramic components if a specific profile is not provided).
7. Packaging and Ordering Information
7.1 Emitter Tape and Reel
The LEDs are supplied on embossed carrier tape wound onto reels. The standard packing quantity is 1000 pieces per reel. The reel and tape dimensions are provided for automated pick-and-place machine setup.
7.2 Moisture Sensitivity and Labeling
The reels are sealed in aluminum moisture-proof bags with desiccant to maintain dryness, as the ceramic package may be moisture-sensitive. The product label on the reel contains critical information including the Part Number (P/N), quantity (QTY), and the specific bin codes for Radiant Flux (CAT), Wavelength (HUE), and Forward Voltage (REF).
7.3 Product Nomenclature Decoding
The full order code, e.g., UVC3535CZ0315-HUC7085020X80300-1T, is a detailed descriptor: UVC (UVC type), 3535 (3.5x3.5mm package), C (Ceramic material), Z (Zener diode for ESD protection integrated), 03 (3 chips), 15 (150° viewing angle), H (Horizontal chip), UC (UVC color), 7085 (270-285nm wavelength), 020 (20mW min. radiant flux), X80 (5.0-8.0V forward voltage), 300 (300mA forward current), 1 (1K pcs packaging), T (Tape packaging).
8. Application Suggestions
8.1 Typical Application Scenarios
The primary application is UV sterilization and disinfection. This includes: stationary air purifiers, HVAC coil treatment, water disinfection units for point-of-use or small-scale systems, surface sanitizers for consumer electronics or medical equipment, and germicidal fixtures. The 150° wide viewing angle makes it suitable for applications requiring area coverage rather than a focused beam.
8.2 Design Considerations
Driver Design: A constant-current driver is mandatory. The driver must be capable of delivering up to 300mA and accommodating the VF range of 5.0-8.0V. Over-current or voltage spikes will severely degrade the LED's lifespan.
Thermal Management: This is the most critical aspect of design. Use a PCB with a thick copper layer (e.g., 2oz) and thermal vias under the thermal pad connected to a large ground plane or an external heatsink. Actively monitor the solder point temperature and use the derating curve to adjust drive current if necessary.
Optical Design: UVC radiation is harmful to human eyes and skin. The end-product must have proper shielding to prevent any direct exposure. The housing material must be UVC-transparent (e.g., fused quartz, special UVC-grade glass) as standard glass and many plastics block UVC.
Safety Compliance: Products using this LED must comply with relevant laser product and radiation safety standards.
9. Technical Comparison and Differentiation
Compared to traditional low-power UVC LEDs or mercury lamps, the UVC3535CZ0315 series offers a solid-state, instant-on, and mercury-free solution. The ceramic package provides a key differentiation from plastic 3535 LEDs by enabling higher power density and better long-term reliability under high-temperature operation. The integrated Zener diode for ESD protection up to 2KV adds robustness not always found in competing products, simplifying supply chain handling and assembly.
10. Frequently Asked Questions (FAQ)
Q: What is the typical lifetime of this LED?
A: LED lifetime is typically defined as the operating hours until the radiant flux degrades to 70% of its initial value (L70). For UVC LEDs, this is highly dependent on drive current and junction temperature. Operating at or below the recommended conditions with excellent thermal management can yield lifetimes of thousands of hours.
Q: Can I drive this LED with a constant voltage source?
A: No. LEDs are current-driven devices. A constant voltage source will lead to thermal runaway and rapid failure due to the negative temperature coefficient of VF. Always use a constant-current driver or a circuit that actively regulates current.
Q: How do I interpret the bin codes on the label?
A: The label shows the specific bins for the LEDs on that reel. For example, CAT:Q5, HUE:U27B, REF:6570 means the LEDs have a radiant flux in the 25-30mW (Q5) bin, a peak wavelength of 275-280nm (U27B), and a forward voltage of 6.5-7.0V (6570).
11. Practical Design Case Study
Consider designing a compact water disinfection module. The goal is to achieve a 3-log (99.9%) reduction of E. coli in a flow-through chamber. The required UVC dose is calculated based on water flow rate, UV transmittance of water, and pathogen susceptibility. Based on the dose, the number of LEDs and their drive current are determined. For example, using 4 LEDs from the Q5 bin (25mW min each) driven at 250mA (slightly derated for reliability) might provide the necessary irradiance. A 4-layer PCB with an internal 2oz copper plane dedicated as a thermal spreader is used. The LEDs are arranged around a quartz sleeve through which water flows. A constant-current driver delivering 1A (250mA x 4 LEDs in parallel, each with its own current-limiting resistor for balance) is selected, with input voltage accommodating the sum of the highest VF bin plus driver overhead. A temperature sensor on the PCB near the LEDs provides feedback to the microcontroller, which can reduce drive current if a high temperature is detected, ensuring long-term reliability.
12. Principle Introduction
UVC light, specifically in the 260-280nm range, is absorbed by the nucleic acids (DNA and RNA) of microorganisms. This absorption causes the formation of thymine dimers in DNA, which disrupts the microorganism's ability to replicate and synthesize vital proteins, effectively inactivating (killing) it. This LED generates this UVC radiation through electroluminescence in a semiconductor material (typically aluminum gallium nitride - AlGaN). When a forward voltage is applied, electrons and holes recombine in the active region of the semiconductor chip, releasing energy in the form of photons. The specific wavelength is determined by the bandgap energy of the semiconductor material.
13. Development Trends
The UVC LED market is driven by the global demand for mercury-free, compact, and instant disinfection solutions. Key trends include: Increasing Wall-Plug Efficiency (WPE): Ongoing research aims to reduce the electrical-to-optical power conversion losses, leading to lower power consumption and heat generation for the same optical output. Higher Output Power: Continuous improvement in chip design and packaging technology enables single-die LEDs with higher radiant flux, reducing the number of LEDs needed per system. Longer Lifetimes: Advancements in materials and packaging are steadily improving device reliability and longevity, especially under high-temperature operation. Reduced Cost: As manufacturing volumes increase and processes mature, the cost per milliwatt of UVC output is decreasing, making the technology viable for more consumer applications. Improved Wavelength Stability: Research focuses on minimizing wavelength shift over temperature and lifetime for more predictable germicidal performance.
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. |