UVC LED LTPL-G35UVC275GC Datasheet - 3.5x3.5mm - 5.7V Typ - 275nm - 19mW Typ - English Technical Document

1. Product Overview

The LTPL-G35UVC product series represents an advanced, energy-efficient solid-state light source engineered for sterilization and medical applications. This technology merges the long operational lifetime and high reliability inherent to Light Emitting Diodes (LEDs) with effective germicidal output, challenging conventional ultraviolet light sources. It provides design flexibility and enables new possibilities for UVC disinfection solutions.

1.1 Core Advantages and Target Market

This UVC LED is designed for applications requiring effective microbial inactivation. Its primary advantages include significantly lower operating and maintenance costs compared to traditional mercury-vapor lamps, driven by higher energy efficiency and a longer lifespan. The device is RoHS compliant and lead-free, aligning with global environmental regulations. It is also IC compatible, facilitating integration into modern electronic control systems. The target markets encompass medical device sterilization, water and air purification systems, and surface disinfection equipment.

2. Technical Parameters: In-Depth Objective Interpretation

2.1 Absolute Maximum Ratings

Operating the device beyond these limits may cause permanent damage. The maximum power dissipation (Po) is 1.1 W. The absolute maximum DC forward current (IF) is 150 mA. The device can operate within an ambient temperature (Topr) range of -40°C to +80°C and be stored (Tstg) from -40°C to +100°C. The maximum allowable junction temperature (Tj) is 105°C. Prolonged operation under reverse bias conditions is not advised as it may lead to component failure.

2.2 Electro-Optical Characteristics at Ta=25°C

Key performance parameters are measured at a standard test current of 120mA. The forward voltage (Vf) has a typical value of 5.7V, with a minimum of 5.0V and a maximum of 7.5V. The radiant flux (Φe), representing the total optical power output, is typically 19 mW, with a minimum of 14 mW. The peak wavelength (λp) is centered in the UVC spectrum, ranging from 265 nm to 280 nm, targeting the DNA/RNA absorption peak for effective disinfection. The thermal resistance from junction to solder point (Rth j-s) is typically 24 K/W, indicating the need for proper thermal management. The viewing angle (2θ1/2) is typically 120 degrees. The device can withstand electrostatic discharge (ESD) up to 2000V (Human Body Model).

2.3 Thermal Characteristics

Effective heat sinking is critical for performance and longevity. The specified thermal resistance (Rth j-s) of 24 K/W is measured using a 2.0 x 2.0 x 0.17 cm aluminum Metal Core Printed Circuit Board (MCPCB). Exceeding the maximum junction temperature of 105°C will accelerate lumen depreciation and can lead to catastrophic failure. Designers must calculate the necessary heatsinking based on the applied power and ambient conditions to maintain the junction within safe limits.

3. Binning System Explanation

To ensure consistency in application design, LEDs are sorted into performance bins.

3.1 Forward Voltage (Vf) Binning

LEDs are categorized into five voltage bins (V1 to V5) at 120mA, each spanning 0.5V from 5.0V to 7.5V. The tolerance for each bin is ±0.1V. This allows designers to select LEDs with similar voltage drops for stable operation in parallel configurations or to predict driver requirements accurately.

3.2 Radiant Flux (Φe) Binning

Optical output is sorted into four flux bins (X1 to X4) at 120mA. X1 covers 14-17 mW, X2 covers 17-20 mW, X3 covers 20-23 mW, and X4 includes devices with 23 mW and above. The tolerance is ±7%. This binning is crucial for applications requiring precise dosage control, as the radiant flux directly impacts the sterilization efficacy.

3.3 Peak Wavelength (Wp) Binning

All devices fall within a single wavelength bin, W1, which spans from 265 nm to 280 nm, with a measurement tolerance of ±3 nm. The bin code is marked on the packaging bag for traceability.

4. Performance Curve Analysis

4.1 Relative Radiant Flux vs. Forward Current

The optical output increases super-linearly with current. While driving at higher currents (up to the absolute maximum of 150mA) yields more output, it also generates significantly more heat, which must be managed to avoid thermal runaway and accelerated degradation.

4.2 Relative Spectral Distribution

The spectral output curve shows a narrow emission band centered in the UVC range. The exact peak wavelength within the 265-280 nm bin affects the microbial inactivation efficiency, as different pathogens have slightly varying absorption spectra.

4.3 Forward Current vs. Forward Voltage (I-V Curve)

This curve demonstrates the diode's exponential relationship between voltage and current. It is essential for designing constant-current drivers, as a small change in voltage can cause a large change in current, affecting both light output and device temperature.

4.4 Relative Radiant Flux vs. Junction Temperature

UVC LED efficiency is highly temperature-sensitive. The radiant flux decreases as the junction temperature rises. This graph quantifies the derating, emphasizing the critical importance of maintaining a low junction temperature for consistent optical performance over the device's lifetime.

4.5 Radiation Pattern

The polar diagram illustrates the typical 120-degree viewing angle, showing the spatial distribution of the emitted UVC radiation. This is important for designing optics or reflectors to direct the germicidal light effectively onto the target surface or volume.

4.6 Forward Current Derating Curve

This curve defines the maximum allowable forward current as a function of the ambient temperature. As ambient temperature increases, the maximum safe operating current must be reduced to prevent the junction temperature from exceeding 105°C.

4.7 Forward Voltage vs. Junction Temperature

The forward voltage has a negative temperature coefficient; it decreases as the junction temperature increases. This property can sometimes be used for indirect temperature monitoring in closed-loop thermal management systems.

5. Mechanical and Package Information

5.1 Outline Dimensions

The package has a footprint of approximately 3.5mm x 3.5mm. All dimensions have a tolerance of ±0.2mm unless otherwise specified. The exact mechanical drawing should be referenced for PCB land pattern design.

5.2 Polarity Identification and Pad Design

The recommended printed circuit board attachment pad layout is provided to ensure reliable soldering and thermal connection. The anode and cathode pads are clearly designated. Adherence to this land pattern is critical for proper alignment, electrical connection, and heat transfer from the LED junction to the PCB.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Profile

A lead-free reflow profile is recommended. Key parameters include: a peak temperature (Tp) of 260°C maximum (245°C recommended), with time above 217°C (tL) between 60-150 seconds. The preheat temperature should be between 150-200°C for 60-120 seconds. The ramp-up rate should not exceed 3°C/second, and the ramp-down rate should not exceed 6°C/second. The total time from 25°C to peak temperature should be under 8 minutes. A rapid cooling process is not recommended.

6.2 Hand Soldering and General Notes

If hand soldering is necessary, the iron tip temperature should not exceed 300°C, and contact time should be limited to 2 seconds maximum, for only one operation. Reflow soldering should not be performed more than three times. All temperature references are for the top side of the package body. The use of dip soldering is not guaranteed. The soldering profile may need adjustment based on the specific solder paste used.

6.3 Cleaning

If cleaning is required after soldering, only alcohol-based solvents like isopropyl alcohol should be used. Unspecified chemical cleaners may damage the LED package material and optical properties.

7. Packaging and Ordering Information

7.1 Tape and Reel Specifications

The LEDs are supplied on embossed carrier tape sealed with a cover tape, wound onto 7-inch reels. A standard reel contains a maximum of 500 pieces, with a minimum packing quantity of 100 pieces for remainders. The packaging conforms to EIA-481-1-B specifications. A maximum of two consecutive missing components in the tape is allowed.

8. Application Suggestions

8.1 Typical Application Scenarios

This UVC LED is suitable for a variety of germicidal applications, including: disinfection of surfaces in medical and laboratory equipment, sterilization of tools, water purification systems for point-of-use or small-scale applications, and air purification in HVAC systems or portable devices. Its solid-state nature makes it ideal for battery-powered or compact designs where mercury lamps are impractical.

8.2 Design Considerations

Drive Method: LEDs are current-operated devices. A constant-current driver is mandatory to ensure stable light output and prevent thermal runaway. When connecting multiple LEDs, series connection is preferred for current uniformity. If parallel connection is unavoidable, individual current-limiting resistors or separate drivers for each branch are strongly recommended to compensate for slight Vf variations between devices.
Thermal Management: This is the single most critical design factor. Use an appropriate MCPCB or other effective heatsinking method to keep the junction temperature as low as possible, ideally below 85°C for maximum lifetime and output stability. The thermal path from the solder point to the ambient must be carefully designed.
Optical Design: Consider the 120-degree viewing angle. For focused applications, secondary optics (lenses or reflectors) made from UVC-transparent materials like quartz or specialized plastics may be required. Ensure all materials in the optical path are resistant to UVC degradation.
Safety: UVC radiation is harmful to human skin and eyes. Enclosures must prevent any leakage of UVC light during operation. Incorporate safety interlocks and warning labels as necessary.

9. Reliability and Lifetime

9.1 Reliability Test Plan

The product undergoes a comprehensive reliability testing regimen including: Room Temperature Operating Life (RTOL) at 120mA for 3000 hours and at 150mA for 1000 hours; High and Low Temperature Storage Life (HTSL/LTSL) at 100°C and -40°C for 1000 hours each; High Temperature & Humidity Storage (WHTSL) at 60°C/90% RH for 1000 hours; and Non-Operating Thermal Shock (TS) from -30°C to 85°C for 100 cycles. Life tests are conducted with the LED mounted on a 90x70x4mm metal heat sink.

9.2 Failure Criteria

A device is considered to have failed if, after testing, the forward voltage (Vf) at 120mA changes by more than ±10% from its initial value, or if the radiant flux (Φe) at 120mA drops below 50% of its initial value.

10. Frequently Asked Questions (Based on Technical Parameters)

Q: What is the typical optical power output?
A: At a drive current of 120mA and 25°C, the typical radiant flux is 19 mW, with devices binned from 14 mW (min) to 23 mW and above.

Q: How do I drive this LED?
A: You must use a constant-current driver. The absolute maximum current is 150mA. A typical operating point is 120mA, yielding 5.7V typical forward voltage. Never connect it directly to a voltage source without current limiting.

Q: Why is thermal management so important?
A: UVC LED efficiency drops significantly with temperature (see Relative Radiant Flux vs. Junction Temperature curve). High junction temperatures also drastically reduce the device's operational lifetime. Proper heatsinking is non-negotiable for reliable performance.

Q: Can I use this for water sterilization?
A: Yes, it is suitable for water purification. The 265-280 nm wavelength is effective against bacteria, viruses, and protozoa. The design must ensure the UVC light penetrates the water effectively, and the LED package must be properly sealed from the environment.

Q: How many times can I reflow solder this component?
A: The recommended maximum is three reflow cycles. Hand soldering should be performed only once, with strict limits on time and temperature.

11. Design and Use Case Example

Scenario: Designing a portable surface disinfection wand.
1. Electrical Design: Use a lithium-ion battery (3.7V nominal) with a boost constant-current driver circuit set to 120mA. The driver must efficiently convert the battery voltage to the ~5.7V required by the LED. 2. Thermal Design: Mount the LED on a small, finned aluminum heatsink. The thermal resistance of the entire path (junction-to-solder, solder-to-heatsink, heatsink-to-ambient) must be calculated to ensure Tj remains below 85°C during the typical 30-60 second operation cycle. Consider active cooling (a small fan) if the wand is intended for prolonged use. 3. Mechanical/Optical Design: House the LED and heatsink in a wand head. Use a quartz lens to focus the 120-degree beam onto a smaller spot for higher irradiance on the target surface. The housing must completely block any UVC leakage to the user. 4. Safety Features: Incorporate a proximity sensor or a physical guard that must be in contact with a surface before the LED turns on. Include a timer to limit exposure duration per activation.

12. Technology Introduction and Trends

12.1 Operating Principle

UVC LEDs are semiconductor devices that emit light in the 200-280 nanometer range when electrical current passes through them. This emission occurs when electrons recombine with electron holes within the device's active region, releasing energy in the form of photons. The specific wavelength is determined by the bandgap energy of the semiconductor materials used, typically aluminum gallium nitride (AlGaN) based compounds for UVC. The emitted UVC radiation inactivates microorganisms by damaging their DNA and RNA, preventing replication.

12.2 Development Trends

The UVC LED market is focused on increasing wall-plug efficiency (optical power output per electrical power input), which historically has been lower than for visible LEDs. Improvements in epitaxial growth, chip design, and package extraction efficiency are steadily driving efficacy higher. Another key trend is increasing output power per chip and per package, enabling more compact and powerful disinfection systems. Research is also ongoing to improve device lifetime and reliability under high-current, high-temperature operating conditions. Cost reduction through manufacturing scale and yield improvement remains a critical driver for broader market adoption against conventional mercury lamp technology.