LTPL-C034UVG365 UV LED Datasheet - 365nm Peak Wavelength - 3.8V Typ. - 4.4W Max. - English Technical Document

1. Product Overview

The product is a high-power ultraviolet (UV) light-emitting diode (LED) designed for demanding applications requiring a solid-state UV light source. It represents an energy-efficient alternative to conventional UV technologies, combining the long operational lifetime and reliability inherent to LED technology with significant radiant output.

Core Advantages:

• IC Compatibility: Designed for easy integration into electronic circuits and control systems.
• Environmental Compliance: The product is RoHS compliant and manufactured using lead-free processes.
• Operational Efficiency: Offers lower operating costs compared to traditional UV sources like mercury lamps.
• Reduced Maintenance: The solid-state nature and long lifespan significantly decrease maintenance requirements and associated costs.
• Design Freedom: Enables new form factors and application designs previously constrained by conventional UV lamp technology.

Target Market: This LED is primarily targeted at applications such as UV curing for inks, adhesives, and coatings, as well as other common UV applications in industrial, medical, and analytical equipment where a reliable, long-lasting 365nm UV source is required.

2. Technical Specifications Deep Dive

2.1 Absolute Maximum Ratings

These ratings define the stress limits beyond which permanent damage to the device may occur. Operation at or near these limits is not recommended for extended periods.

• DC Forward Current (If): 1000 mA (Maximum continuous current).
• Power Consumption (Po): 4.4 W (Maximum power dissipation).
• Operating Temperature Range (Topr): -40°C to +85°C (Ambient temperature range for normal operation).
• Storage Temperature Range (Tstg): -55°C to +100°C (Temperature range for non-operational storage).
• Junction Temperature (Tj): 125°C (Maximum temperature allowed at the semiconductor junction).

Important Note: Prolonged operation under reverse bias conditions can lead to component failure.

2.2 Electro-Optical Characteristics (Ta=25°C)

These are the typical performance parameters measured under standard test conditions (Forward Current, If = 700mA).

• Forward Voltage (Vf): 3.8 V (Typical), with a range from 3.2 V (Min.) to 4.4 V (Max.). This parameter is crucial for driver design.
• Radiant Flux (Φe): 1300 mW (Typical), with a range from 1050 mW (Min.) to 1545 mW (Max.). This measures the total optical power output in the UV spectrum.
• Peak Wavelength (λp): Centered in the 365nm region, with a bin range from 360nm to 370nm. This defines the primary UV emission peak.
• Viewing Angle (2θ_1/2): 130° (Typical). This indicates a wide radiation pattern.
• Thermal Resistance (R_thjs): 5.1 °C/W (Typical, Junction-to-Solder point). A lower value indicates better heat transfer from the chip to the board, which is critical for maintaining performance and longevity.

2.3 Thermal Characteristics

Effective thermal management is paramount for LED performance and reliability. The thermal resistance of 5.1°C/W specifies how much the junction temperature will rise for every watt of power dissipated. To keep the junction temperature within safe limits (below 125°C), proper heatsinking and PCB thermal design are essential, especially when operating at the maximum current of 700mA or 1000mA.

3. Binning System Explanation

To ensure consistency in application performance, LEDs are sorted (binned) based on key parameters. The bin code is marked on the packaging.

3.1 Forward Voltage (Vf) Binning

LEDs are grouped by their forward voltage drop at 700mA.

• V1 Bin: 3.2V to 3.6V
• V2 Bin: 3.6V to 4.0V
• V3 Bin: 4.0V to 4.4V

Tolerance: ±0.1V. Selecting a specific bin can help in designing more uniform driver circuits.

3.2 Radiant Flux (mW) Binning

LEDs are sorted by their optical power output at 700mA. This is critical for applications requiring consistent UV intensity.

• PR Bin: 1050 mW to 1135 mW
• RS Bin: 1135 mW to 1225 mW
• ST Bin: 1225 mW to 1325 mW
• TU Bin: 1325 mW to 1430 mW
• UV Bin: 1430 mW to 1545 mW

Tolerance: ±10%.

3.3 Peak Wavelength (Wp) Binning

LEDs are categorized based on their peak emission wavelength.

• P3M Bin: 360 nm to 365 nm
• P3N Bin: 365 nm to 370 nm

Tolerance: ±3nm. This allows selection for processes sensitive to specific UV wavelengths.

4. Performance Curve Analysis

4.1 Relative Radiant Flux vs. Forward Current

This curve shows that radiant flux increases with forward current but not linearly. It tends to saturate at higher currents due to increased thermal effects and efficiency droop. Operating at the typical 700mA provides a good balance of output and efficiency.

4.2 Relative Spectral Distribution

The spectral plot confirms the narrowband emission characteristic of LEDs, with a dominant peak around 365nm and minimal sideband emission. This is advantageous for processes requiring specific UV activation without excess heat or unwanted wavelengths.

4.3 Radiation Pattern

The radiation characteristic diagram illustrates the wide 130-degree viewing angle, showing the intensity distribution as a function of angle from the LED's central axis. This pattern is important for designing illumination optics for uniform coverage.

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

This fundamental curve demonstrates the diode's exponential relationship between current and voltage. The "knee" voltage is around 3V. The driver must be a current source to ensure stable operation, as a small change in voltage can cause a large change in current.

4.5 Relative Radiant Flux vs. Junction Temperature

This critical curve shows the negative impact of rising junction temperature on light output. As Tj increases, radiant flux decreases. This underscores the necessity of effective thermal management to maintain consistent performance over the LED's lifetime.

4.6 Forward Current Derating Curve

This graph specifies the maximum allowable forward current as a function of the ambient or case temperature. To prevent exceeding the maximum junction temperature, the drive current must be reduced when operating in higher temperature environments.

5. Mechanical and Package Information

5.1 Outline Dimensions

The device has a specific surface-mount package footprint. Key dimensional tolerances are:

• General dimensions: ±0.2mm
• Lens height and ceramic substrate length/width: ±0.1mm

The thermal pad (typically for heatsinking) is electrically isolated (neutral) from the anode and cathode electrical pads.

5.2 Recommended PCB Attachment Pad Layout

A suggested land pattern (footprint) for the PCB is provided to ensure proper soldering, thermal transfer, and mechanical stability. Adhering to this layout is recommended for reliable assembly.

5.3 Polarity Identification

The datasheet includes markings or diagrams to identify the anode and cathode terminals. Correct polarity connection is essential for device operation.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Profile

A detailed temperature-time profile for reflow soldering is provided. Key parameters include a peak package body temperature and specific ramp-up/cool-down rates. Notes emphasize:

• Avoiding rapid cooling processes.
• Using the lowest possible soldering temperature.
• The profile may need adjustment based on solder paste used.
• Dip soldering is not recommended or guaranteed.

6.2 Hand Soldering

If hand soldering is necessary, the maximum recommended condition is 300°C for a maximum of 2 seconds, and this should be performed only once per device.

6.3 Cleaning

Only alcohol-based solvents like isopropyl alcohol (IPA) should be used for cleaning. Unspecified chemicals may damage the LED package.

7. Packaging and Ordering Information

7.1 Tape and Reel Specifications

The LEDs are supplied on embossed carrier tape and reels for automated assembly.

• Detailed dimensions for the tape pockets and the reel are provided.
• Empty pockets are sealed with cover tape.
• A 7-inch reel can hold a maximum of 500 pieces.
• Packaging conforms to EIA-481-1-B standards.

8. Application Suggestions

8.1 Typical Application Scenarios

• UV Curing: Curing of inks, coatings, adhesives, and resins in printing, electronics assembly, and dental applications.
• Fluorescence Excitation: Causing materials to fluoresce for inspection, authentication, or analysis.
• Disinfection: While 365nm is not the optimal germicidal wavelength (UVC), it can be used in some photochemical processes.
• Medical Therapy: Certain phototherapy treatments.

8.2 Design Considerations

• Current Drive: Always use a constant current driver, not a constant voltage source, to ensure stable operation and prevent thermal runaway.
• Thermal Management: Design the PCB with adequate thermal vias, copper area, and consider an external heatsink if operating at high currents or in high ambient temperatures.
• Optics: Lenses or reflectors may be needed to collimate or shape the wide beam angle for specific applications.
• ESD Protection: LEDs are sensitive to electrostatic discharge. Implement standard ESD handling precautions during assembly.
• Eye and Skin Safety: 365nm UV-A radiation can be harmful. Implement appropriate shielding, interlocks, and user warnings in the final product.

9. Reliability and Testing

The product undergoes a comprehensive suite of reliability tests, with results showing zero failures in the sample sizes tested. Tests include:

• Low, Room, and High Temperature Operating Life (LTOL, RTOL, HTOL).
• Wet High Temperature Operating Life (WHTOL).
• Thermal Shock (TMSK).
• Resistance to Soldering Heat (Reflow).
• Solderability Test.

Failure criteria are defined by shifts in Forward Voltage (±10%) and Radiant Flux (±30%) from initial values. These tests validate the product's robustness for industrial applications.

10. Technical Comparison and Trends

10.1 Advantages vs. Conventional UV Sources

Compared to mercury-vapor UV lamps, this LED offers:

• Instant On/Off: No warm-up or cool-down time.
• Longer Lifetime: Tens of thousands of hours vs. thousands for lamps.
• Higher Efficiency: More UV output per electrical watt input.
• Compact Size & Design Flexibility: Enables smaller, more innovative equipment.
• No Mercury: Environmentally safer disposal.
• Precise Wavelength: Narrow spectral output targets specific photo-initiators.

10.2 Development Trends

The UV LED market is driven by trends towards:

• Higher Radiant Flux: Increasing power density from single emitters and modules.
• Improved Wall-Plug Efficiency (WPE): Reducing heat generation for a given optical output.
• Lower Cost per Radiant Watt: Making LED solutions economically viable for more applications.
• Expansion into UVC Bands: For direct germicidal (265nm-280nm) applications, although this product is in the UV-A band.

11. Frequently Asked Questions (Based on Technical Data)

11.1 What driver current should I use?

The electro-optical characteristics are specified at 700mA, which is the recommended typical operating current for balanced performance and lifetime. It can be driven up to the absolute maximum of 1000mA, but this will require exceptional thermal management and may reduce lifespan. Always refer to the derating curve for temperature-dependent current limits.

11.2 How do I interpret the bin codes?

Bin codes ensure you receive LEDs with consistent performance. For example, ordering from the "TU" flux bin and "P3N" wavelength bin guarantees devices with 1325-1430 mW output and 365-370 nm peak wavelength. Specify the required bins for your application to guarantee system performance.

11.3 How critical is thermal management?

Extremely critical. The junction temperature directly impacts light output (see Relative Flux vs. Tj curve) and long-term reliability. Exceeding the maximum junction temperature of 125°C will accelerate degradation and can cause rapid failure. The 5.1°C/W thermal resistance value is key for calculating the required heatsinking.

11.4 Can I use a voltage source to power this LED?

No. LEDs are current-driven devices. Their forward voltage has tolerance and varies with temperature. A constant voltage source would lead to uncontrolled current, likely exceeding maximum ratings and destroying the LED. A constant current driver or a current-limiting circuit is mandatory.

12. Practical Design and Usage Case

Scenario: Designing a UV Spot Curing System

1. Requirement: A handheld device for curing dental adhesives, requiring a focused 365nm UV spot of consistent intensity for 10-second cycles.
2. LED Selection: This 365nm LED is chosen for its high radiant flux and appropriate wavelength.
3. Driver Design: A compact, battery-powered constant current driver set to 700mA is developed, with a timer circuit for the 10-second pulse.
4. Thermal Design: The LED is mounted on a small metal-core PCB (MCPCB) within the handheld tool's body, which acts as a heatsink. The duty cycle (10s on, 50s off) helps manage heat buildup.
5. Optical Design: A simple collimating lens is placed over the LED to focus the wide 130° beam into a smaller, more intense spot at the working distance.
6. Result: A reliable, instant-on curing tool that outperforms older bulb-based systems in size, speed, and lifetime, with no warm-up delay for the dentist.

13. Operating Principle

This device is a semiconductor light source. When a forward voltage is applied across the anode and cathode, electrons and holes recombine within the active region of the semiconductor chip (typically based on materials like AlGaN or InGaN for UV emission). This recombination process releases energy in the form of photons (light). The specific bandgap energy of the semiconductor materials used determines the wavelength of the emitted photons, which in this case is in the ultraviolet-A (UV-A) spectrum around 365 nanometers. The wide viewing angle is a result of the package design and the primary lens over the chip.