SMD LED LTSA-G6SVUWETU Datasheet - White Light, Yellow Lens - Electrical & Optical Specifications

1. Product Overview

This document details the specifications for a high-performance Surface-Mount Device (SMD) Light Emitting Diode (LED). The device is designed for automated assembly processes and is suitable for a wide range of electronic equipment where space efficiency and reliability are critical. The LED features a white light source, achieved through InGaN technology, and is encapsulated within a yellow-tinted lens, which can influence the final perceived color and light diffusion characteristics.

The core advantages of this component include its compliance with RoHS directives, compatibility with automatic placement and infrared reflow soldering equipment, and qualification according to the AEC-Q101 standard for automotive-grade components. Its primary target markets include automotive accessory applications, portable electronics, computing devices, and network systems.

2. Technical Parameters Deep Dive

2.1 Absolute Maximum Ratings

The device's operational limits are defined at an ambient temperature (Ta) of 25°C. The absolute maximum power dissipation is 900 mW. It can handle a DC forward current ranging from 5 mA to 250 mA. For pulsed operation, a peak forward current of 500 mA is permissible under a 1/10 duty cycle with a 0.1ms pulse width. The operating and storage temperature range is specified from -40°C to +110°C. It is crucial to note that this LED is not designed for reverse voltage operation.

2.2 Electrical & Optical Characteristics

Measured at Ta=25°C and a forward current (IF) of 140mA, the key performance parameters are defined. The luminous intensity (Iv) has a typical range from 11.2 cd to 22.0 cd. The viewing angle (2θ1/2), representing the angle where intensity is half the axial value, is typically 120 degrees, indicating a wide beam pattern. The forward voltage (VF) typically falls between 2.8V and 3.6V at the test current. The chromaticity coordinates (Cx, Cy) are centered around (0.33, 0.34), defining the white point in the CIE color space. Reverse current (IR) is typically 2 μA at a reverse voltage (VR) of 5V, though reverse operation is not intended.

2.3 Thermal Characteristics

Effective thermal management is vital for LED performance and longevity. The thermal resistance from the junction to the ambient (RθJA) is typically 45 °C/W, measured on a standard FR4 substrate with a 16mm² pad. More significantly, the thermal resistance from the junction to the solder point (RθJS) is typically 25 °C/W, highlighting the importance of a well-designed PCB thermal pad. The maximum allowable junction temperature (Tj) is 150°C.

3. Binning System Explanation

The LEDs are sorted into bins based on key parameters to ensure consistency in application. The bin code is typically presented in the format: Vf / Iv / CIE (e.g., 64/FA/IM).

3.1 Forward Voltage (Vf) Binning

LEDs are categorized into four voltage bins at 140mA: Bin 24 (2.8-3.0V), Bin 64 (3.0-3.2V), Bin A4 (3.2-3.4V), and Bin E4 (3.4-3.6V). A tolerance of ±0.1V applies to each bin.

3.2 Luminous Intensity (Iv) Binning

Three intensity bins are defined at 140mA: Bin FA (11.2-14.0 cd, ~37.8 lm typ.), Bin FB (14.0-18.0 cd, ~48.0 lm typ.), and Bin GA (18.0-22.0 cd, ~58.0 lm typ.). A tolerance of ±11% applies to each bin.

3.3 Color (Chromaticity) Binning

The white color point is tightly controlled through CIE chromaticity coordinate binning. Multiple bins are defined (e.g., GM, HM, IM, JM, KM) with specific quadrilateral boundaries on the CIE 1931 (x, y) diagram. The typical target is around (0.33, 0.34). A tolerance of ±0.01 is maintained for the x and y coordinates within each hue bin.

4. Performance Curve Analysis

While specific graphical data is referenced in the datasheet (e.g., Figure 2: Spatial Distribution), typical curves for such LEDs would illustrate the relationship between forward current and luminous intensity (showing sub-linear roll-off at high currents), forward voltage vs. temperature, and the relative intensity vs. wavelength (spectral power distribution). The spatial distribution plot confirms the wide 120-degree viewing angle, showing how light intensity decreases off-axis.

5. Mechanical & Package Information

The LED comes in a standard EIA package format suitable for SMD assembly. The cathode lead frame is explicitly designated as the primary heat sink for the device, which is critical for PCB layout design to ensure optimal thermal performance. Detailed dimensional drawings specify the package outline, lead spacing, and overall size, with tolerances typically within ±0.1 mm. The lens color is yellow while the emitted light is white.

6. Soldering & Assembly Guidelines

6.1 IR Reflow Soldering Profile

The datasheet recommends an infrared reflow profile compliant with J-STD-020 for lead-free solder processes. This profile typically includes specific ramp-up rates, a preheat/soak zone, a time above liquidus (TAL), a peak temperature, and controlled cooling rates to prevent thermal shock to the component.

6.2 Recommended PCB Pad Design

A suggested printed circuit board attachment pad layout is provided to ensure reliable soldering and effective heat dissipation from the cathode thermal pad.

6.3 Cleaning

If cleaning is required after soldering, only immersion in ethyl alcohol or isopropyl alcohol at normal temperature for less than one minute is recommended. The use of unspecified chemicals should be avoided as they may damage the package.

6.4 Storage & Handling

The product is classified as Moisture Sensitivity Level (MSL) 2 per JEDEC J-STD-020. When the moisture-proof bag is sealed with desiccant, storage should be at ≤30°C and ≤70% RH, with a shelf life of one year. Once opened, the components should be stored at ≤30°C and ≤60% RH and should undergo reflow soldering within one year. For extended storage outside the original packaging, appropriate dry storage conditions are essential.

7. Packaging & Ordering Information

The LEDs are supplied in a tape-and-reel format compatible with automated pick-and-place machines. The tape width is 12mm, wound on a standard 7-inch (178mm) diameter reel. Each reel contains 1000 pieces. For quantities less than a full reel, a minimum packing quantity of 500 pieces is specified for remainders. The packaging conforms to ANSI/EIA 481 specifications.

8. Application Suggestions

8.1 Typical Application Scenarios

This LED is well-suited for automotive interior and accessory lighting, backlighting for indicators in consumer electronics (phones, notebooks), status indicators in networking equipment, and general-purpose illumination in compact devices.

8.2 Design Considerations

Thermal Management: Due to the power dissipation (up to 900mW) and thermal resistance figures, designing an adequate thermal path from the cathode pad to the PCB copper pour or an external heatsink is paramount to maintain junction temperature below 150°C and ensure long-term reliability and stable light output.
Current Driving: A constant current driver is recommended over a constant voltage source to ensure consistent luminous intensity and color point. The driver should be designed to operate within the specified DC forward current range (5-250mA).
Optical Design: The wide 120-degree viewing angle makes it suitable for applications requiring broad illumination without secondary optics. For focused beams, external lenses or reflectors would be necessary.

9. Technical Comparison & Differentiation

Key differentiating factors for this LED include its AEC-Q101 qualification, making it suitable for demanding automotive environments beyond basic consumer electronics. The combination of a high-power rating (900mW), relatively low thermal resistance junction-to-solder point (25°C/W), and detailed three-dimensional binning (Vf, Iv, CIE) offers designers a component with predictable performance for color-critical and thermally constrained applications. The explicit designation of the cathode as the heat sink simplifies thermal management design.

10. Frequently Asked Questions (Based on Technical Parameters)

Q: Can I drive this LED with a 5V supply?
A: Not directly. The forward voltage is typically between 2.8V and 3.6V. Connecting it directly to a 5V source would cause excessive current and immediate failure. A current-limiting resistor or, preferably, a constant-current driver circuit must be used.

Q: What is the difference between luminous intensity (cd) and luminous flux (lm)?
A: Luminous intensity measures the brightness of the LED in a specific direction (candelas). Luminous flux measures the total visible light output in all directions (lumens). The datasheet provides typical lumen equivalents for the intensity bins, but the primary spec is intensity due to the directional nature of the measurement.

Q: Why is the thermal resistance to the solder point (RθJS) lower than to ambient (RθJA)?
A: RθJS measures the thermal path from the silicon junction directly to the solder pads on your PCB. RθJA includes the additional resistance from the PCB to the surrounding air. RθJS is more useful for designing the PCB's thermal management, as it shows how effective your board layout is at pulling heat from the LED itself.

Q: What does "Not designed for reverse operation" mean?
A: It means the LED should never be subjected to a reverse voltage bias in normal circuit operation. While a small reverse current (2μA at 5V) is specified for test purposes, applying reverse voltage in a live circuit can damage the device.

11. Practical Application Case

Scenario: Dashboard Indicator for an Automotive Accessory.
A designer needs a bright, reliable status indicator for a new aftermarket car accessory. They select this LED in bin 64/FA/IM. They design a PCB with a generously sized copper pour connected to the cathode pad for heat sinking. A simple constant-current circuit set to 140mA is implemented using a driver IC. The wide 120-degree viewing angle ensures the indicator is visible from various seating positions. The AEC-Q101 qualification provides confidence in the component's ability to withstand the automotive temperature range and vibration. The specific binning ensures consistent color and brightness across all production units.

12. Operating Principle Introduction

This is a solid-state light source based on a semiconductor p-n junction. When a forward voltage exceeding the diode's threshold is applied, electrons and holes recombine within the active region (made of InGaN materials), releasing energy in the form of photons. The primary emission from the InGaN chip is in the blue or ultraviolet spectrum. To produce white light, this primary emission is converted using a phosphor layer inside the package. The blue/UV photons excite the phosphors, which then re-emit light across a broader spectrum (yellow, red), mixing with the remaining blue light to create the perception of white. The yellow-tinted external lens acts as a final filter/diffuser, potentially slightly warming the color temperature and spreading the light.

13. Technology Trends

The general trend in SMD LEDs like this one is towards higher efficacy (more lumens per watt), improved color rendering index (CRI) for better color accuracy, and tighter binning tolerances for applications like display backlighting. There is also a continuous push for higher power density and lower thermal resistance packages to enable brighter outputs from smaller footprints. The adoption of new phosphor technologies and chip designs aims to provide more stable color performance over temperature and lifetime. The drive for miniaturization continues while maintaining or improving optical and thermal performance.