LTPL-C034UVD405 UV LED Datasheet - 3.5x3.5x1.6mm - 3.5V Typ - 460-700mW - 405nm Peak Wavelength - English Technical Document

1. Product Overview

The C03 UV Product series represents an advanced, energy-efficient light source engineered for UV curing and general ultraviolet applications. This technology merges the longevity and reliability inherent to Light Emitting Diodes with the high brightness levels traditionally associated with conventional UV sources. This fusion provides significant design flexibility and opens new avenues for solid-state UV lighting to replace older, less efficient UV technologies.

1.1 Core Advantages and Target Market

This product is designed for applications requiring precise, reliable, and efficient ultraviolet emission. Its primary advantages include full compatibility with integrated circuit (I.C.) drive systems, adherence to RoHS compliance and lead-free (Pb-free) manufacturing standards, which contribute to lower operational and reduced maintenance costs over the product's lifecycle. The target market encompasses industrial curing processes, medical and scientific instrumentation, counterfeit detection, and any application where controlled UV exposure is critical.

2. Technical Parameters: In-Depth Objective Interpretation

The following section provides a detailed, objective analysis of the device's key technical parameters as defined under standard test conditions (Ta=25°C).

2.1 Absolute Maximum Ratings

These ratings define the limits beyond which permanent damage to the device may occur. Operation at or near these limits is not recommended for extended periods. The maximum DC forward current (If) is 500 mA. The maximum power consumption (Po) is 2 Watts. The device can operate within an ambient temperature range (Topr) of -40°C to +85°C and be stored (Tstg) between -55°C and +100°C. The maximum allowable junction temperature (Tj) is 110°C. It is critically important to avoid operating the LED under reverse bias conditions for prolonged periods, as this can lead to component failure.

2.2 Electro-Optical Characteristics

These characteristics define the device's performance under typical operating conditions (If = 350mA). The forward voltage (Vf) ranges from a minimum of 2.8V to a maximum of 4.4V, with a typical value of 3.5V. The total radiant flux output (Φe), measured with an integrating sphere, ranges from 460mW to 700mW, with a typical value of 620mW. The peak wavelength (Wp) is specified between 400nm and 410nm, placing it firmly in the near-ultraviolet spectrum. The viewing angle (2θ1/2) is typically 130 degrees, indicating a wide radiation pattern. The thermal resistance from junction to case (Rth jc) is typically 14.7 °C/W, with a measurement tolerance of ±10%.

2.3 Thermal Characteristics

Effective thermal management is paramount for LED performance and longevity. The specified thermal resistance (Rth jc) of 14.7 °C/W indicates the temperature rise per watt of power dissipated between the semiconductor junction and the package case. A lower value is preferable. This parameter, combined with the maximum junction temperature of 110°C, dictates the necessary heat sinking requirements for any given application to ensure the LED operates within its safe operating area and maintains its rated output and lifetime.

3. Bin Code System Explanation

The product is classified into bins based on key performance parameters to ensure consistency for the end-user. The bin code is marked on each packing bag.

3.1 Forward Voltage (Vf) Binning

LEDs are sorted into four voltage bins (V0, V1, V2, V3) at a test current of 350mA. V0 bins have voltages between 2.8V and 3.2V, V1 between 3.2V and 3.6V, V2 between 3.6V and 4.0V, and V3 between 4.0V and 4.4V. The tolerance for this classification is ±0.1V. This allows designers to select LEDs with closely matched forward voltages for parallel connections or precise current regulation.

3.2 Radiant Flux (Φe) Binning

The optical output power is categorized into six bins (R1 through R6). R1 represents the lowest output range (460-500 mW), and R6 represents the highest (660-700 mW), all measured at 350mA. The tolerance for radiant flux is ±10%. This binning enables selection based on required light intensity for the application.

3.3 Peak Wavelength (Wp) Binning

The emitted wavelength is sorted into two primary bins: P4A (400-405 nm) and P4B (405-410 nm), with a tolerance of ±3nm. This is crucial for applications sensitive to specific UV wavelengths, such as initiating particular photochemical reactions in curing processes.

4. Performance Curve Analysis

Graphical data provides insight into the device's behavior under varying conditions.

4.1 Relative Radiant Flux vs. Forward Current

This curve typically shows a sub-linear relationship where radiant flux increases with forward current but may exhibit saturation or efficiency droop at higher currents. The exact operating point (e.g., 350mA) should be chosen to balance output and efficiency while staying within absolute maximum ratings.

4.2 Relative Spectral Distribution

This graph depicts the intensity of light emitted across different wavelengths, centered around the peak wavelength (400-410nm). It shows the spectral bandwidth, which is important for applications where spectral purity or a specific wavelength interaction is required.

4.3 Radiation Characteristics

This polar plot illustrates the spatial distribution of light intensity, correlating to the 130-degree viewing angle. It shows how light is emitted from the LED package, which is vital for optical system design to ensure proper illumination of the target area.

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

This fundamental curve shows the exponential relationship typical of a diode. The forward voltage increases with current. The curve's shape is essential for designing the appropriate driver circuitry, whether it's a simple current-limiting resistor or a constant-current driver.

4.5 Relative Radiant Flux vs. Junction Temperature

This critical curve demonstrates the negative impact of rising junction temperature on light output. As the junction temperature increases, the radiant flux decreases. This underscores the importance of effective thermal management to maintain consistent optical performance over time and under different ambient conditions.

5. Mechanical and Package Information

5.1 Outline Dimensions

The device has a compact surface-mount package. Key dimensions include a body size and lens profile. All linear dimensions are in millimeters. General dimension tolerances are ±0.2mm, while the lens height and ceramic substrate length/width have tighter tolerances of ±0.1mm. The thermal pad on the bottom of the device is electrically isolated (floating) from the anode and cathode pads, meaning it can be connected directly to a PCB thermal plane for heat dissipation without creating an electrical short.

5.2 Polarity Identification and Pad Design

The recommended printed circuit board (PCB) attachment pad layout is provided to ensure proper soldering and thermal performance. The design includes separate pads for the anode and cathode, as well as a larger pad for the thermal connection. Correct polarity orientation during assembly is essential for device operation.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Parameters

A detailed reflow soldering profile is recommended. Key parameters include preheat, soak, reflow peak temperature, and cooling rates. The maximum peak temperature (measured on the package body surface) should be controlled. A rapid cooling process is not recommended. It is advised to use the lowest possible soldering temperature that achieves a reliable joint. The device can withstand a maximum of three reflow cycles. Hand soldering, if necessary, should be limited to a maximum of 300°C for no more than 2 seconds, applied only once.

6.2 Cleaning and Handling Precautions

If cleaning is required after soldering, only alcohol-based solvents like isopropyl alcohol should be used. Unspecified chemical cleaners may damage the LED package. General ESD (electrostatic discharge) precautions should be observed during handling.

7. Packaging and Ordering Information

7.1 Tape and Reel Specifications

The LEDs are supplied in embossed carrier tape sealed with a top cover tape. The tape is wound onto reels. A standard 7-inch reel can hold a maximum of 500 pieces. The packaging conforms to EIA-481-1-B specifications. There is a specification that no more than two consecutive component pockets on the tape may be empty.

8. Application Suggestions

8.1 Typical Application Scenarios

This UV LED is suitable for a variety of applications including, but not limited to: UV curing of adhesives, inks, and coatings; fluorescence excitation for analysis or inspection; medical and biological instrumentation; air and water purification systems; and counterfeit detection (e.g., verifying security features).

8.2 Design Considerations and Drive Method

An LED is a current-operated device. To ensure uniform intensity when multiple LEDs are connected in parallel within a single application, it is strongly recommended to incorporate an individual current-limiting resistor in series with each LED. This compensates for minor variations in forward voltage (Vf) between individual devices, preventing current hogging where one LED draws more current than others, leading to uneven brightness and potential overstress. A constant-current driver circuit is the optimal solution for driving one or multiple LEDs in series, providing stable performance regardless of forward voltage variations.

9. Reliability and Testing

The device undergoes a comprehensive reliability test plan to ensure robustness. Tests include Low Temperature Operating Life (LTOL at -30°C), Room Temperature Operating Life (RTOL), High Temperature Operating Life (HTOL at 85°C), Wet High Temperature Operating Life (WHTOL at 60°C/60% RH), Thermal Shock (TMSK from -40°C to 125°C), Resistance to Soldering Heat (simulating reflow), and Solderability testing. Specific pass/fail criteria are defined based on changes in forward voltage (within ±10%) and radiant flux (within ±15%) after testing. All life tests are conducted with the device mounted on a thermal heat sink.

10. Technical Comparison and Differentiation

Compared to traditional UV light sources like mercury-vapor lamps, this solid-state LED solution offers distinct advantages: instant on/off capability with no warm-up time, significantly longer operational lifetime (often tens of thousands of hours), higher energy efficiency converting more electrical power into useful UV light, absence of hazardous materials like mercury, compact size enabling new form factors, and precise spectral output. The main trade-off historically was lower total optical power, but modern high-power UV LEDs like this series are closing that gap for many applications.

11. Frequently Asked Questions (Based on Technical Parameters)

11.1 What is the difference between radiant flux (mW) and luminous flux (lm)?

Radiant flux (Φe) measures the total optical power emitted in all directions, in Watts. This is the correct metric for UV LEDs as it quantifies the actual UV energy. Luminous flux (lumens) measures perceived brightness by the human eye, weighted by the photopic response curve, and is not applicable to non-visible UV sources.

11.2 How do I select the correct bin for my application?

Choose the voltage bin (Vf) based on your driver circuit design and need for current matching in parallel strings. Select the radiant flux bin (Φe) based on the required intensity or irradiance at your target. Choose the wavelength bin (Wp) if your process is sensitive to a specific spectral peak (e.g., 405nm vs. 400nm).

11.3 Why is thermal management so critical?

High junction temperature directly reduces light output (as shown in the performance curves) and accelerates the degradation mechanisms within the semiconductor, drastically shortening the device's operational lifetime. Proper heat sinking is non-negotiable for reliable, long-term performance.

12. Practical Design and Usage Case

Case: Designing a PCB for a multi-LED UV curing spot. A designer needs to create an array of 10 LEDs for a small-area curing application. Based on the datasheet: 1) They select LEDs from the same Vf and Φe bin for consistency. 2) They design the PCB with the recommended pad layout, connecting the thermal pads to a large copper pour on the board connected to vias for heat dissipation to the bottom layer or an external heatsink. 3) They decide to drive the LEDs with a constant-current driver set to 350mA. Since they want to connect all 10 in parallel for uniform illumination, they include a small, individual current-limiting resistor (e.g., 1 Ohm) in series with each LED to compensate for Vf variations, as recommended. 4) They follow the reflow profile guidelines during assembly. 5) In the final product firmware, they may implement a temperature monitoring or derating algorithm based on the "Relative Radiant Flux vs. Junction Temperature" curve if the ambient conditions are variable.

13. Operating Principle Introduction

This device is a semiconductor light-emitting diode (LED). When a forward voltage is applied across the anode and cathode, electrons and holes are injected into the active region of the semiconductor chip. These charge carriers recombine, releasing energy in the form of photons (light). The specific wavelength of the emitted photons (in this case, ~405nm, in the ultraviolet-A spectrum) is determined by the bandgap energy of the semiconductor materials used in the chip's construction (typically based on aluminum gallium nitride - AlGaN). The generated light is then shaped and emitted through the integrated lens of the package.

14. Technology Trends

The field of UV LEDs is characterized by ongoing research and development aimed at increasing wall-plug efficiency (optical power out / electrical power in), achieving higher output power from a single device or smaller package, extending operational lifetime, and pushing emission wavelengths deeper into the UV-C spectrum (for germicidal applications) with improved efficiency. There is also a trend towards more sophisticated packaging to enhance light extraction and thermal performance. The drive to replace mercury-based UV lamps across all applications continues to be a major market force, supported by environmental regulations and the performance benefits of solid-state lighting.