LTPL-C036UVG365 UV LED Datasheet - 3.6x3.0x1.6mm - 3.6V - 2.94W - 365nm - English Technical Documentation

1. Product Overview

The LTPL-C036UVG365 is a high-performance, energy-efficient ultraviolet (UV) light-emitting diode (LED) designed primarily for UV curing applications and other common UV processes. This product represents a solid-state lighting solution that combines the long operational lifetime and reliability inherent to LED technology with a high level of radiant output, challenging conventional UV light sources. It offers designers significant freedom in system integration, enabling new opportunities to replace older UV technologies like mercury-vapor lamps in various industrial and commercial settings.

1.1 Key Features and Advantages

The device incorporates several features that make it suitable for modern electronic and industrial applications:

• Integrated Circuit (IC) Compatibility: The LED is designed to be easily driven and controlled by standard electronic circuits, facilitating integration into automated systems.
• Environmental Compliance: The product is compliant with the Restriction of Hazardous Substances (RoHS) directive and is manufactured using lead-free (Pb-free) materials, aligning with global environmental standards.
• Operational Efficiency: It offers lower operating costs compared to traditional UV sources due to higher electrical-to-optical conversion efficiency and reduced power consumption.
• Reduced Maintenance: The solid-state nature and long lifespan of LEDs significantly lower maintenance frequency and associated costs, minimizing system downtime.

2. Technical Specifications Deep Dive

2.1 Absolute Maximum Ratings

These ratings define the limits beyond which permanent damage to the device may occur. They are specified at an ambient temperature (Ta) of 25°C.

• DC Forward Current (If): 700 mA (maximum)
• Power Consumption (Po): 2.94 W (maximum)
• Operating Temperature Range (Topr): -40°C to +85°C
• Storage Temperature Range (Tstg): -55°C to +100°C
• Junction Temperature (Tj): 110°C (maximum)

Important Note: Operating the LED under reverse bias conditions for extended periods can lead to component failure.

2.2 Electro-Optical Characteristics

These are the typical performance parameters measured at Ta=25°C and a forward current (If) of 500mA, which is a common test and operating condition.

• Forward Voltage (Vf): Typical value is 3.6V, with a range from 2.8V (Min) to 4.4V (Max).
• Radiant Flux (Φe): This is the total optical power output in the UV spectrum. The typical value is 905 mW, ranging from a minimum of 762 mW to a maximum of 1123 mW. It is measured using an integrating sphere.
• Peak Wavelength (λp): The wavelength at which the LED emits the most optical power. For this model, it is centered around 365nm, with a range from 360nm to 370nm.
• Viewing Angle (2θ1/2): The full angle at which the radiant intensity is half of the maximum intensity (typically measured at 0°). This LED has a typical viewing angle of 55°.
• Thermal Resistance (Rthjs): This parameter, typically 5.0 °C/W, indicates the resistance to heat flow from the semiconductor junction to the solder point. A lower value signifies better heat dissipation capability.

3. Bin Code System Explanation

The LEDs are sorted into performance bins based on key parameters to ensure consistency in application. The bin code is marked on each packaging bag.

3.1 Forward Voltage (Vf) Binning

LEDs are categorized into three voltage bins (V1, V2, V3) when driven at 500mA. This helps in designing power supplies and current-limiting circuits for consistent performance across multiple LEDs, especially when connected in parallel.

3.2 Radiant Flux (mW) Binning

The optical output power is binned into five categories (NO, OP, PR, RS, ST), each representing a specific range of minimum and maximum radiant flux at 500mA. This allows designers to select LEDs with the desired brightness level for their application.

3.3 Peak Wavelength (Wp) Binning

The UV emission wavelength is binned into two groups: P3M (360-365nm) and P3N (365-370nm). This is critical for applications like UV curing, where specific wavelengths are required to initiate photochemical reactions in resins and inks.

4. Performance Curve Analysis

The datasheet provides several characteristic curves that illustrate the device's behavior under different conditions.

4.1 Relative Radiant Flux vs. Forward Current

This curve shows how the optical output increases with the drive current. It is typically non-linear, and operating beyond the recommended current may not yield proportional increases in output while generating excessive heat.

4.2 Relative Spectral Distribution

This graph depicts the intensity of light emitted across different wavelengths, confirming the narrowband UV emission centered around 365nm.

4.3 Radiation Pattern

The polar diagram illustrates the spatial distribution of light, showing the 55° viewing angle characteristic. This is important for designing optics to direct the UV light onto the target area.

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

This fundamental curve shows the exponential relationship between current and voltage. It is essential for designing the driver circuit to ensure stable operation.

4.5 Relative Radiant Flux vs. Junction Temperature

This critical curve demonstrates the negative impact of rising junction temperature on light output. As temperature increases, the radiant flux decreases. This underscores the importance of effective thermal management in the application to maintain performance and longevity.

5. Mechanical and Package Information

5.1 Outline Dimensions

The LTPL-C036UVG365 is a surface-mount device (SMD). Key package dimensions are approximately 3.6mm in length, 3.0mm in width, and 1.6mm in height (including lens). The lens height and ceramic substrate dimensions have tighter tolerances (±0.1mm) compared to other body dimensions (±0.2mm). The device features a thermal pad that is electrically isolated (neutral) from the anode and cathode electrical pads, allowing it to be used for heat sinking without creating an electrical short.

5.2 Recommended PCB Attachment Pad Layout

A detailed land pattern (footprint) is provided for printed circuit board (PCB) design. This includes the size and spacing for the two electrical pads (anode and cathode) and the central thermal pad. Proper pad design is crucial for reliable soldering and optimal heat transfer from the LED junction to the PCB.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Profile

A detailed temperature-time profile for reflow soldering is provided. Key parameters include:

• Preheat: Ramp from 150°C to 200°C at a maximum rate of 3°C/second.
• Soak/Reflow: Maintain between 200°C and 250°C for 60-120 seconds, then ramp to a peak temperature of 260°C (maximum) for 10-30 seconds.
• Cooling: Cool down to below 150°C. A rapid cooling process is not recommended.

6.2 Hand Soldering

If hand soldering is necessary, the iron tip temperature should not exceed 300°C, and contact time should be limited to a maximum of 2 seconds per solder joint. Reflow soldering is preferred and should not be performed more than three times on the same device.

6.3 Cleaning

If cleaning is required after soldering, only alcohol-based solvents like isopropyl alcohol (IPA) should be used. Unspecified chemical cleaners may damage the LED package material (e.g., the lens or encapsulant).

7. Packaging and Handling

7.1 Tape and Reel Specifications

The LEDs are supplied in embossed carrier tape on reels for automated pick-and-place assembly. The tape dimensions and reel specifications (7-inch reel holding up to 500 pieces) conform to the EIA-481-1-B standard. The tape pockets are sealed with a cover tape to protect the components.

8. Reliability Testing

The device has undergone a comprehensive suite of reliability tests to ensure robust performance under various stress conditions. Tests include Low/High Temperature Operating Life (LTOL/HTOL), Room Temperature Operating Life (RTOL), Wet High Temperature Operating Life (WHTOL), Thermal Shock (TMSK), and High Temperature Storage. All tests reported zero failures out of ten samples, indicating high reliability. The pass/fail criteria are based on changes in forward voltage (within ±10%) and radiant flux (within ±15%) after testing.

9. Application Notes and Design Considerations

9.1 Drive Circuit Design

LEDs are current-operated devices. To ensure uniform intensity when connecting multiple LEDs in parallel, it is strongly recommended to use a dedicated current-limiting resistor in series with each LED. This compensates for minor variations in the forward voltage (Vf) between individual devices, preventing current hogging where one LED draws more current than others, leading to uneven brightness and potential overstress.

9.2 Thermal Management

Effective heat sinking is paramount. The 5.0 °C/W thermal resistance from junction to solder point means that for every watt of power dissipated (not just optical power, but electrical power converted to heat), the junction temperature will rise 5°C above the solder point temperature. The PCB should be designed with adequate thermal vias and copper pours connected to the thermal pad to conduct heat away. Maintaining a low junction temperature is critical for achieving rated luminous output, long lifespan, and preventing premature failure.

9.3 Typical Application Scenarios

• UV Curing: Curing of adhesives, inks, coatings, and resins in manufacturing, printing, and 3D printing.
• Medical and Scientific: Sterilization equipment, fluorescence analysis, and phototherapy devices.
• Forensics and Authentication: Revealing security markings, counterfeit detection.
• Industrial Inspection: Detecting flaws or contaminants using fluorescence.

10. Technical Comparison and Advantages

Compared to traditional UV sources like mercury arc lamps, the LTPL-C036UVG365 UV LED offers distinct advantages:

• Instant On/Off: No warm-up or cool-down time required.
• Long Lifetime: Tens of thousands of hours vs. thousands for traditional lamps.
• Narrowband Emission: Targeted 365nm output reduces unwanted heat and ozone generation.
• Compact Size and Design Flexibility: Enables smaller, more efficient system designs.
• Lower Total Cost of Ownership: Due to higher efficiency, less maintenance, and longer life.

11. Frequently Asked Questions (FAQs)

11.1 What is the difference between Radiant Flux and Luminous Flux?

Radiant Flux (Φe), measured in watts (mW here), is the total optical power emitted across all wavelengths. Luminous Flux, measured in lumens, is weighted by the sensitivity of the human eye. Since this is a UV LED invisible to humans, its performance is specified in Radiant Flux.

11.2 Can I drive this LED at 700mA continuously?

The Absolute Maximum Rating for forward current is 700mA. For reliable, long-term operation, it is advisable to operate below this maximum, typically at or below the test condition of 500mA, with appropriate thermal management. Exceeding maximum ratings voids reliability guarantees.

11.3 How do I interpret the Bin Code?

Select a bin that meets your application's requirements for voltage consistency (for parallel strings) and minimum radiant output. For wavelength-sensitive applications like curing, choose the appropriate P3M or P3N bin to match your photo-initiator's activation spectrum.

12. Design and Usage Case Study

Scenario: Designing a UV Curing Station for PCB Conformal Coating. A designer needs to cure a UV-sensitive acrylic coating on assembled PCBs. They select the LTPL-C036UVG365 in the PR flux bin and P3M wavelength bin to match the coating's cure spectrum. An array of 20 LEDs is planned. To ensure even curing, each LED is driven by a constant current driver set to 500mA, with a series resistor for each LED as per the datasheet recommendation. The LEDs are mounted on an aluminum core PCB with a designed thermal pad layout to dissipate the approximately 30W of total heat. The reflow profile from the datasheet is used for assembly. This setup provides fast, reliable curing with low energy consumption and maintenance.

13. Operating Principle

A Light Emitting Diode (LED) is a semiconductor device that emits light when an electric current passes through it. In a UV LED like the LTPL-C036UVG365, electrons recombine with electron holes within the device's active region, releasing energy in the form of photons. The specific semiconductor materials (typically based on aluminum gallium nitride - AlGaN) are engineered so that the energy bandgap corresponds to ultraviolet light, resulting in emission at a peak wavelength of approximately 365 nanometers.

14. Technology Trends

The UV LED market is experiencing significant growth, driven by the phase-out of mercury-based lamps and demand for more efficient, compact solutions. Key trends include:

• Increasing Output Power and Efficiency: Ongoing materials and packaging research continues to push the radiant flux per device higher while improving wall-plug efficiency.
• Shorter Wavelengths: Development of LEDs emitting in the UVC band (200-280nm) for germicidal applications is a major focus area.
• Improved Thermal Management: Advanced package designs with lower thermal resistance are critical for enabling higher power densities.
• Cost Reduction: As manufacturing volumes increase and yields improve, the cost per milliwatt of UV output is steadily decreasing, broadening the adoption of UV LED technology across industries.