LTPL-C16FUVM375 UV LED Datasheet - 3.2x1.6x1.9mm - 3.5V - 160mW - 375nm Peak Wavelength - English Technical Document

1. Product Overview

The LTPL-C16 series represents a significant advancement in solid-state lighting technology, specifically engineered for ultraviolet (UV) applications. This product is an energy-efficient and ultra-compact light source that merges the long operational lifetime and high reliability inherent to Light Emitting Diodes (LEDs) with performance levels suitable for displacing conventional UV lighting systems. It offers designers considerable freedom in product development due to its small form factor and surface-mount design, enabling new possibilities in UV-based processes and equipment.

1.1 Key Features and Advantages

The core advantages of this component stem from its design and manufacturing process. It is fully compatible with standard automated pick-and-place equipment, facilitating high-volume, cost-effective assembly on printed circuit boards (PCBs). The package is qualified for both infrared (IR) and vapor phase reflow soldering processes, adhering to standard Pb-free and RoHS-compliant manufacturing requirements. Its EIA (Electronic Industries Alliance) standard footprint ensures interoperability and ease of integration into existing design libraries and assembly lines. Furthermore, the device is designed to be directly compatible with integrated circuit (IC) drive levels, simplifying the surrounding control electronics.

1.2 Target Applications

This UV LED is specifically targeted at industrial and manufacturing processes that utilize ultraviolet light. Primary application areas include UV curing of adhesives, resins, and coatings, where precise and rapid polymerization is required. It is also suitable for UV marking and coding systems. Another significant use case is in the drying and curing of specialized printing inks. The 375nm wavelength is particularly effective in initiating photochemical reactions for these purposes.

2. Mechanical and Package Information

The device is housed in a compact surface-mount package. The outline dimensions are critical for PCB layout and thermal management. The package body measures approximately 3.2mm in length, 1.6mm in width, and has a height of 1.9mm. All dimensional tolerances are typically ±0.1mm unless otherwise specified on the detailed mechanical drawing. The component features a clear lens for optimal light extraction.

2.1 PCB Attachment Pad Layout

For reliable soldering, a recommended PCB land pattern (footprint) is provided. This pattern is optimized for infrared or vapor phase reflow soldering processes. The pad design ensures proper solder fillet formation, mechanical stability, and effective thermal transfer from the LED die to the PCB, which is crucial for managing junction temperature and maintaining long-term reliability.

2.2 Polarity Identification

The component has a designated cathode and anode. Polarity is typically indicated by a marking on the package body, such as a notch, dot, or cut corner. Correct polarity orientation during assembly is mandatory, as applying a reverse voltage exceeding the absolute maximum rating can cause immediate damage to the device.

3. Absolute Maximum Ratings

These ratings define the stress limits beyond which permanent damage to the device may occur. Operation under or at these limits is not guaranteed and should be avoided for reliable performance.

• Power Dissipation (Po): 160 mW. This is the maximum allowable power loss within the device at an ambient temperature (Ta) of 25°C.
• DC Forward Current (If): 40 mA. The maximum continuous forward current that can be applied.
• Reverse Voltage (Vr): 5 V. The maximum voltage that can be applied in the reverse direction.
• Operating Temperature Range (Topr): -40°C to +85°C. The ambient temperature range over which the device is designed to function.
• Storage Temperature Range (Tstg): -40°C to +100°C.
• Junction Temperature (Tj): 90°C. The maximum allowable temperature at the semiconductor junction itself.

4. Electro-Optical Characteristics

These parameters are measured at a standard test condition of Ta=25°C and a forward current (If) of 20mA, unless stated otherwise. They define the typical performance of the device.

• Radiant Flux (Φe): 14 mW (Min), 20 mW (Typ), 28 mW (Max). This is the total optical power output in the UV spectrum, measured in milliwatts.
• Viewing Angle (2θ1/2): 135 degrees (Typ). This defines the angular spread of the emitted radiation where the intensity is half of the peak intensity.
• Peak Wavelength (λp): 370 nm (Min), 375 nm (Typ), 380 nm (Max). The wavelength at which the spectral radiant intensity is maximum.
• Forward Voltage (Vf): 2.8 V (Min), 3.5 V (Typ), 4.0 V (Max). The voltage drop across the LED when operating at the specified forward current.
• Reverse Current (Ir): 10 µA (Max) at Vr=1.2V. This parameter is tested to verify the Zener characteristic but the device is not intended for reverse operation.

5. Bin Code and Classification System

To manage production variances and allow for precise selection, LEDs are sorted into performance bins based on key parameters. The bin code is marked on the packaging.

5.1 Forward Voltage (Vf) Binning

Devices are categorized into three voltage bins: V1 (2.8V-3.2V), V2 (3.2V-3.6V), and V3 (3.6V-4.0V). This allows designers to select LEDs with similar voltage drops for consistent performance in parallel arrays or to match specific driver requirements.

5.2 Radiant Flux (Φe) Binning

Optical output is binned across a wide range to ensure intensity matching. Bins range from R3 (14-16 mW) to R9 (26-28 mW). Selecting LEDs from the same or adjacent flux bins is critical for applications requiring uniform illumination.

5.3 Peak Wavelength (λp) Binning

The UV wavelength is binned into two primary groups: P3P (370-375 nm) and P3Q (375-380 nm). This ensures spectral consistency for processes sensitive to a specific UV activation wavelength.

6. Performance Curve Analysis

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

6.1 Relative Radiant Flux vs. Forward Current

This curve shows that the optical output is not linearly proportional to current. It increases with current but may exhibit saturation or reduced efficiency at very high currents due to thermal effects and internal quantum efficiency droop. Operating significantly above the typical 20mA test point requires careful thermal management.

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

The I-V characteristic is exponential, typical of a diode. The curve shows the threshold voltage (where current begins to flow significantly) and how the forward voltage increases with current. This information is vital for designing constant-current drivers.

6.3 Relative Radiant Flux vs. Junction Temperature

This is one of the most critical curves for design. It demonstrates the negative impact of temperature on light output. As the junction temperature (Tj) rises, the radiant flux decreases. Effective heat sinking and PCB thermal design are essential to maintain high output and long life. The curve quantifies the derating factor.

6.4 Relative Emission Spectrum

The spectral distribution graph shows the intensity of emitted radiation across wavelengths. It confirms the peak at ~375nm and shows the spectral bandwidth (Full Width at Half Maximum - FWHM), which is important for applications where specific photoreactions are targeted.

7. Assembly and Handling Guidelines

7.1 Soldering Process Recommendations

The device is rated for Pb-free reflow soldering. A detailed temperature profile is provided, specifying pre-heat, soak, reflow, and cooling stages. Key parameters include a peak body temperature not exceeding 260°C and a time above 240°C of less than 10 seconds. Rapid cooling rates are not recommended. Hand soldering with an iron is possible but must be limited to 300°C for a maximum of 3 seconds per lead, only once.

7.2 Electrostatic Discharge (ESD) Precautions

This LED is sensitive to electrostatic discharge. Proper ESD controls must be in place during handling and assembly. This includes the use of grounded wrist straps, anti-static mats, and ESD-safe packaging and equipment. Failure to observe ESD precautions can lead to latent or catastrophic device failure.

7.3 Cleaning

If post-solder cleaning is necessary, only specified solvents should be used. Immersing the LED in ethyl alcohol or isopropyl alcohol at room temperature for less than one minute is acceptable. Harsh or unspecified chemicals can damage the epoxy lens and package, leading to reduced light output or premature failure.

7.4 Moisture Sensitivity and Storage

The package is rated Moisture Sensitivity Level (MSL) 3 per JEDEC standard J-STD-020. When the moisture-proof bag is sealed, the devices have a shelf life of one year when stored at ≤ 30°C and ≤ 90% RH. Once the bag is opened, the components must be used within 168 hours (7 days) if stored at ≤ 30°C and ≤ 60% RH. If the humidity indicator card turns pink or the time limit is exceeded, a bake-out at 60°C for at least 48 hours is required before reflow to prevent \"popcorning\" damage during soldering.

8. Packaging and Ordering Information

The components are supplied on embossed carrier tape for automated handling. The tape dimensions are specified to be compatible with standard feeders. The tape is wound onto 7-inch (178mm) reels. A typical reel contains 1500 pieces. The packaging conforms to EIA-481-1-B specifications. The top cover tape seals the component pockets. Quality specifications allow for a maximum of two consecutive missing components on a reel.

9. Application Design Considerations

9.1 Drive Circuit Design

An LED is a current-operated device. For stable and consistent operation, it must be driven by a constant current source, not a constant voltage. When connecting multiple LEDs, series connection is preferred as it ensures identical current through each device. If parallel connection is unavoidable, individual current-limiting resistors should be used for each LED branch to compensate for variances in forward voltage (Vf) and prevent current hogging, which can lead to uneven brightness and potential overstress of one device.

9.2 Thermal Management

Managing the junction temperature is paramount for performance and lifetime. The maximum junction temperature is 90°C. The designer must calculate the thermal resistance from the junction to the ambient (Rth j-a) based on the PCB layout, copper area, and possible use of thermal vias. The power dissipated (Pd = Vf * If) must be managed to keep Tj within limits, especially considering the derating of light output with temperature shown in the performance curves. A well-designed thermal pad on the PCB is essential.

9.3 Optical Design

The 135-degree viewing angle provides a broad emission pattern. For applications requiring focused or collimated UV light, secondary optics such as lenses or reflectors may be necessary. The material of these optics must be transparent to UV radiation (e.g., specialized glasses or UV-stable plastics like PMMA).

10. Reliability and Application Notes

The product is designed for use in standard commercial and industrial electronic equipment. For applications requiring exceptional reliability where failure could jeopardize safety (e.g., aviation, medical life-support, transportation safety systems), a specific consultation and potential qualification process is necessary, as the standard product data may not cover such extreme use cases. The lifetime of the LED is strongly influenced by operating conditions, primarily junction temperature and drive current. Operating below absolute maximum ratings and implementing robust thermal design will maximize operational lifespan.