UV LED Chip LTPL-C034UVG395 Datasheet - 395nm Peak Wavelength - 3.6V Typ. Forward Voltage - 4.4W Max. Power - English Technical Document

1. Product Overview

The LTPL-C034UVG395 is a high-performance, energy-efficient ultraviolet (UV) light source engineered for demanding applications such as UV curing and other industrial processes requiring UV radiation. This product represents a significant advancement by merging the long operational lifespan and inherent reliability of Light Emitting Diodes (LEDs) with the high radiant output traditionally associated with conventional UV lamps like mercury vapor. This combination provides designers with greater freedom, enabling the creation of more compact, efficient, and durable systems while opening new opportunities for solid-state lighting to replace older, less efficient UV technologies.

1.1 Key Features and Advantages

• Integrated Circuit (IC) Compatibility: Designed for easy integration into modern electronic control systems.
• Environmental Compliance: Fully compliant with RoHS (Restriction of Hazardous Substances) directives and manufactured using lead-free (Pb-free) processes.
• Operational Efficiency: Offers significantly lower operating costs compared to traditional UV sources due to higher electrical-to-optical conversion efficiency.
• Reduced Maintenance: The solid-state nature of LEDs eliminates components like filaments or electrodes that degrade over time, leading to dramatically reduced maintenance requirements and costs.
• Instant On/Off: Provides immediate full output upon activation and can be switched on and off rapidly without degradation, unlike some conventional sources.

2. Technical Specifications and In-Depth Interpretation

2.1 Absolute Maximum Ratings

These ratings define the limits beyond which permanent damage to the device may occur. Operation under these conditions is not guaranteed.

• 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).
• Storage Temperature Range (Tstg): -55°C to +100°C.
• Junction Temperature (Tj): 125°C (maximum temperature at the semiconductor junction).

Critical Note: Prolonged operation under reverse bias conditions can lead to component failure. Proper circuit design must prevent this.

2.2 Electro-Optical Characteristics at Ta=25°C

These parameters are measured under standard test conditions (If = 700mA, Ta=25°C) and represent the core performance metrics.

• Forward Voltage (Vf): Typical value is 3.6V, with a range from 3.2V (Min.) to 4.4V (Max.). This parameter is crucial for driver design and thermal management.
• Radiant Flux (Φe): The total optical power output in the UV spectrum. Typical value is 1415 mW (1.415 W), ranging from 1225 mW to 1805 mW. This high output is key for effective curing.
• Peak Wavelength (Wp): The wavelength at which the LED emits the most power. It is centered around 395nm, with a bin range from 390nm to 400nm. This places it in the near-UV (UVA) spectrum.
• Viewing Angle (2θ1/2): Approximately 130 degrees. This wide beam angle is beneficial for applications requiring broad area illumination.
• Thermal Resistance (Rthjs): Typical value is 4.1 °C/W (junction to solder point). This low value indicates good thermal conduction from the chip to the board, which is essential for managing heat at high drive currents.

3. Bin Code Classification System

To ensure consistency in production, LEDs are sorted into performance bins. The bin code is marked on the packaging.

3.1 Forward Voltage (Vf) Binning

• V1: 3.2V – 3.6V
• V2: 3.6V – 4.0V
• V3: 4.0V – 4.4V

3.2 Radiant Flux (Φe) Binning

• ST: 1225 – 1325 mW
• TU: 1325 – 1430 mW
• UV: 1430 – 1545 mW
• VW: 1545 – 1670 mW
• WX: 1670 – 1805 mW

3.3 Peak Wavelength (Wp) Binning

• P3T: 390 – 395 nm
• P3U: 395 – 400 nm

4. Performance Curve Analysis

4.1 Relative Radiant Flux vs. Forward Current

The radiant output increases super-linearly with current. While driving at higher currents (up to the maximum rating) yields more UV output, it also generates significantly more heat. The optimal drive current is a balance between desired output and thermal management constraints.

4.2 Relative Spectral Distribution

The emission spectrum is centered at 395nm with a typical full width at half maximum (FWHM) of approximately 15-20nm. This narrow bandwidth is advantageous for processes sensitive to specific wavelengths.

4.3 Radiation Pattern

The polar diagram confirms the wide 130-degree viewing angle, showing a near-Lambertian emission pattern suitable for area illumination.

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

This curve shows the exponential relationship typical of diodes. The forward voltage increases with current and is also temperature-dependent. Accurate driver design requires consideration of this characteristic.

4.5 Relative Radiant Flux vs. Junction Temperature

UV LED output is highly sensitive to junction temperature. The curve typically shows a negative coefficient, meaning radiant flux decreases as junction temperature rises. Effective heat sinking is critical to maintain stable, high output.

4.6 Forward Current Derating Curve

This graph defines the maximum allowable forward current as a function of the ambient or case temperature. To ensure the junction temperature stays below 125°C, the drive current must be reduced when operating at higher ambient temperatures.

5. Mechanical and Package Information

5.1 Outline Dimensions

The device features a surface-mount package. Critical dimensions include the body size, lens height, and the location/size of the anode, cathode, and thermal pad. The thermal pad is electrically isolated (neutral) from the electrical contacts, allowing it to be connected directly to a PCB ground plane for optimal heat dissipation. All dimensional tolerances are ±0.2mm, except for the lens height and ceramic substrate dimensions, which are held to a tighter tolerance of ±0.1mm.

5.2 Recommended PCB Attachment Pad Layout

A detailed land pattern diagram is provided to ensure reliable soldering and thermal performance. The design includes separate pads for the anode, cathode, and a large central thermal pad. Following this recommended footprint is essential for mechanical stability, electrical connection, and most importantly, transferring heat from the LED junction to the printed circuit board.

6. Soldering and Assembly Guidelines

6.1 Suggested Reflow Soldering Profile

A detailed temperature vs. time graph is provided for lead-free (Pb-free) reflow soldering. Key parameters include:

• Preheat: Gradual ramp to activate flux.
• Soak Zone: Allows for temperature stabilization across the board.
• Reflow (Liquidus): Peak temperature should not exceed 260°C measured on the package body surface, with time above 240°C limited to a recommended maximum.
• Cooling: A controlled, non-rapid cool-down rate is recommended to prevent thermal shock.

6.2 Important Assembly Notes

• Reflow soldering is the preferred method. Hand soldering, if necessary, should be limited to 300°C max for 2 seconds maximum, only once.
• The reflow process should not be performed more than three times on the same device.
• Dip soldering is not recommended or guaranteed.
• Always use the lowest possible soldering temperature that achieves a reliable joint.

6.3 Cleaning

If cleaning is required after soldering, use only alcohol-based solvents such as isopropyl alcohol. Unspecified chemical cleaners may damage the LED package material (e.g., the lens or encapsulant).

7. Reliability and Quality Assurance

An extensive suite of reliability tests has been conducted, with zero failures reported from the sample lots, demonstrating high product robustness.

• Operating Life Tests (LTOL, RTOL, HTOL): 1000 hours of continuous operation under various temperature and current stress conditions.
• Environmental Stress Tests: Includes Wet High Temperature Operating Life (WHTOL), Thermal Shock (TMSK), Resistance to Soldering Heat (simulating reflow), and Solderability tests.
• Failure Criteria: Post-test, devices are judged based on forward voltage shift (must remain within ±10% of initial) and radiant flux degradation (must remain within -30% of initial).

8. Packaging and Handling

8.1 Tape and Reel Specifications

The components are supplied on embossed carrier tape wound onto 7-inch reels, in accordance with EIA-481-1-B standards. The tape dimensions, pocket size, and reel hub details are provided. Each reel can contain a maximum of 500 pieces. The packaging ensures components are protected during shipping and are compatible with automated pick-and-place assembly equipment.

9. Application Notes and Design Considerations

9.1 Drive Method

LEDs are current-operated devices. To ensure consistent and uniform radiant output, as well as to prevent thermal runaway, they must be driven by a constant current source, not a constant voltage source. The driver circuit should be designed to supply the required current (e.g., 700mA for typical specs) while compensating for the forward voltage variations indicated in the binning tables.

9.2 Thermal Management

This is the single most critical aspect of designing with high-power UV LEDs. The low thermal resistance (4.1 °C/W) is only effective if the heat is efficiently conducted away from the solder point. This requires:

• A PCB with sufficient thermal vias under the thermal pad.
• A high-thermal-conductivity PCB material (e.g., metal-core or insulated metal substrate) for high-power applications.
• Potentially, an additional external heatsink.
• Adherence to the current derating curve based on the actual operating ambient temperature.

9.3 Typical Application Scenarios

• UV Curing: Adhesives, inks, coatings, and resins in manufacturing processes.
• Medical and Scientific Equipment: Sterilization, fluorescence analysis, phototherapy.
• Forensics and Authentication: Currency verification, document analysis.
• Industrial Inspection: Detecting flaws or contaminants.

10. Technical Comparison and Advantages

Compared to traditional medium-pressure mercury UV lamps, this UV LED solution offers:

• Significantly Longer Lifetime: Tens of thousands of hours vs. a few thousand hours.
• Instantaneous Operation: No warm-up time required.
• Higher Efficiency: More UV output per watt of electrical input, reducing energy costs.
• Eco-Friendly: Contains no mercury, is RoHS compliant, and reduces hazardous waste.
• Compact Size and Design Flexibility: Enables smaller, more innovative system designs.
• Precise Wavelength Control: Narrow spectrum output can be tailored to specific photo-initiators in curing applications, improving process efficiency.