LTPL-C034UVG385 UV LED Datasheet - 385nm Peak Wavelength - 3.6V Typ. Forward Voltage - 4.4W Max. Power - English Technical Document

1. Product Overview

The LTPL-C034UVG385 is a high-power ultraviolet (UV) light-emitting diode (LED) designed for demanding applications such as UV curing and other common UV processes. This product represents a significant advancement in solid-state UV lighting technology, offering a combination of high radiant flux output, energy efficiency, and long operational lifetime. It is engineered to provide a reliable and cost-effective alternative to traditional UV light sources, enabling greater design flexibility and new opportunities in various industrial and commercial settings.

Key advantages of this LED include its compatibility with integrated circuits (I.C. compatible), compliance with environmental standards (RoHS compliant and lead-free), and the potential for lower overall operating and maintenance costs compared to conventional UV lamps. The device is built to deliver consistent performance within a specified operating temperature range.

2. Technical Specifications and Deep Objective Interpretation

2.1 Absolute Maximum Ratings

The device must not be operated beyond these limits to prevent permanent damage. The maximum DC forward current (If) is 1000 mA, with a maximum power consumption (Po) of 4.4 Watts. The operating temperature range (Topr) is specified from -40°C to +85°C, while the storage temperature range (Tstg) is wider, from -55°C to +100°C. The maximum allowable junction temperature (Tj) is 125°C. It is critically important to avoid prolonged reverse bias operation, as this can lead to component failure.

2.2 Electro-Optical Characteristics

All measurements are taken at an ambient temperature (Ta) of 25°C and a test current (If) of 700mA, which is considered a typical operating point.

• Forward Voltage (Vf): The voltage drop across the LED when conducting current. It has a typical value of 3.6V, with a minimum of 3.2V and a maximum of 4.4V. This parameter is crucial for driver design and power supply selection.
• Radiant Flux (Φe): The total optical power output, measured in milliwatts (mW). The typical value is 1415 mW, with a range from 1225 mW (min) to 1805 mW (max). This is a direct measure of the UV light output power.
• Peak Wavelength (Wp): The wavelength at which the LED emits the most optical power. For this model, it is in the 380-390 nm range, categorizing it as a UVA LED. This wavelength is critical for matching the absorption spectrum of photoinitiators in curing applications.
• Viewing Angle (2θ1/2): The full angle at which the radiant intensity is half of the maximum intensity (typically measured). This LED has a typical viewing angle of 130°, indicating a relatively wide beam pattern.
• Thermal Resistance (Rthjs): The thermal resistance from the LED junction to the solder point, with a typical value of 4.1 °C/W. This low value indicates good thermal conduction from the chip to the board, which is essential for managing heat and maintaining performance and longevity.

3. Binning System Explanation

The LEDs are sorted into performance bins to ensure consistency. The bin code is marked on each packaging bag.

3.1 Forward Voltage (Vf) Binning

LEDs are grouped into three voltage bins (V1, V2, V3) based on their forward voltage at 700mA, with tolerances of ±0.1V. This allows designers to select LEDs with similar electrical characteristics for parallel arrays to ensure current sharing.

3.2 Radiant Flux (mW) Binning

The optical output power is binned into five categories (ST, TU, UV, VW, WX), with a tolerance of ±10%. This enables selection based on required light output levels for a given application.

3.3 Peak Wavelength (Wp) Binning

The wavelength is binned into two ranges: P3R (380-385 nm) and P3S (385-390 nm), with a tolerance of ±3nm. This precise sorting is vital for applications sensitive to specific UV wavelengths.

4. Performance Curve Analysis

4.1 Relative Radiant Flux vs. Forward Current

The radiant flux increases with forward current but not linearly. The curve shows the relationship, helping designers optimize the drive current for the desired output while considering efficiency and thermal management.

4.2 Relative Spectral Distribution

This graph depicts the intensity of light emitted across different wavelengths, centered around the peak wavelength (385nm typ.). It shows the spectral bandwidth of the LED.

4.3 Radiation Characteristics

This polar diagram illustrates the spatial distribution of light intensity (radiation pattern) relative to the viewing angle, confirming the 130° typical beam profile.

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 understanding the dynamic resistance of the LED and for designing constant-current drivers.

4.5 Relative Radiant Flux vs. Junction Temperature

This curve demonstrates the negative impact of increasing junction temperature on light output. As temperature rises, radiant flux decreases. Effective heat sinking is necessary to maintain performance.

4.6 Forward Current Derating Curve

This graph specifies the maximum allowable forward current as a function of the case temperature (Tc). To ensure reliability and prevent overheating, the drive current must be reduced when operating at higher ambient temperatures.

5. Mechanical and Package Information

5.1 Outline Dimensions

The datasheet provides detailed mechanical drawings with all critical dimensions in millimeters. Key tolerances are noted: ±0.2mm for most dimensions, and ±0.1mm for lens height and ceramic substrate length/width. The thermal pad is noted as electrically isolated (neutral) from the anode and cathode pads.

5.2 Recommended PCB Attachment Pad

A land pattern design is provided for the printed circuit board (PCB). This includes the recommended pad layout for the anode, cathode, and thermal pad to ensure proper soldering, electrical connection, and heat dissipation.

6. Soldering and Assembly Guidelines

6.1 Suggested Reflow Soldering Profile

A detailed temperature vs. time profile is provided for reflow soldering. Key parameters include a preheat zone, a ramp to a peak temperature (referring to the package body surface), and a controlled cooling phase. A rapid cooling process is not recommended. The profile should be adjusted based on the specific solder paste used.

6.2 Hand Soldering and General Notes

If hand soldering is used, the iron tip temperature should not exceed 300°C, and contact time should be limited to a maximum of 2 seconds, performed only once. Reflow soldering should be performed a maximum of three times. The lowest possible soldering temperature is always desirable to minimize thermal stress on the LED component.

7. Packaging and Ordering Information

7.1 Tape and Reel Specifications

The LEDs are supplied on embossed carrier tape sealed with a cover tape. The tape is wound onto 7-inch reels, with a maximum capacity of 500 pieces per reel. Packaging conforms to EIA-481-1-B specifications. The maximum number of consecutive missing components in the tape is two.

8. Application Suggestions

8.1 Typical Application Scenarios

The primary application for this LED is UV curing, used in processes such as adhesive bonding, ink drying, coating hardening, and 3D printing (stereolithography). Other common UV applications include fluorescence inspection, counterfeit detection, and medical/biological analysis.

8.2 Design Considerations

• Driver Design: LEDs are current-operated devices. A constant current driver is mandatory to ensure stable light output and prevent thermal runaway. Intensity matching in multi-LED arrays requires careful selection from the same or adjacent flux bins.
• Thermal Management: Effective heat sinking is critical. The low thermal resistance (4.1 °C/W) facilitates heat transfer, but a properly designed heatsink or metal-core PCB is necessary to keep the junction temperature within safe limits, especially at high drive currents or in high ambient temperatures.
• Optics: The 130° viewing angle may require secondary optics (lenses or reflectors) to collimate or focus the beam for specific applications.

9. Reliability and Testing

The datasheet includes results from a comprehensive suite of reliability tests conducted on sample lots. Tests include Low/High Temperature Operating Life (LTOL/HTOL), Thermal Shock (TMSK), and Solderability tests. All tests reported zero failures out of ten samples under the specified conditions (e.g., 1000 hours at 700mA and 85°C case temperature for HTOL). The criteria for judging failure are defined as a change in forward voltage beyond ±10% or a change in radiant flux beyond ±30% from initial values.

10. Cautions and Handling

10.1 Cleaning

If cleaning is necessary after soldering, only alcohol-based solvents such as isopropyl alcohol should be used. Unspecified chemical cleaners may damage the LED package material.

10.2 Drive Method Reminder

The document reiterates that an LED is a current-operated device. To ensure uniform intensity in arrays, current regulation and proper bin selection are essential.

11. Operational Principle Introduction

Ultraviolet LEDs operate on the same fundamental principle as visible LEDs, based on electroluminescence in semiconductor materials. When a forward voltage is applied across the p-n junction, electrons and holes recombine, releasing energy in the form of photons. The specific semiconductor compounds used in the chip's active region determine the wavelength (color) of the emitted light. For UVA LEDs like the LTPL-C034UVG385, materials such as aluminum gallium nitride (AlGaN) are typically used to achieve the 385nm emission peak. The wide viewing angle is a result of the package design and the primary lens encapsulating the semiconductor chip.

12. Technology Trends and Comparison

This LED exemplifies the ongoing trend of solid-state lighting displacing conventional technologies in the UV spectrum. Compared to traditional UV sources like mercury-vapor lamps, UV LEDs offer significant advantages: instant on/off capability, no hazardous materials (mercury-free), longer lifetime, higher energy efficiency, compact size, and design flexibility due to their low-voltage DC operation. The main trade-offs have historically been lower output power and higher cost per emitted watt, but products like the LTPL-C034UVG385, with radiant flux exceeding 1.4 Watts, demonstrate that high-power UV LEDs are now viable for an expanding range of industrial applications. The key differentiator for this specific product in its class is its combination of high radiant flux (up to 1805mW) at a standard 700mA drive current with a relatively low thermal resistance, enabling robust performance in demanding environments.