LTW-010DCG-TR LED Datasheet - 3.0x1.6x1.6mm - 3.4V - 120mW - White Light - English Technical Document

1. Product Overview

The LTW-010DCG-TR is a surface-mount white light-emitting diode (LED) designed as an energy-efficient and compact light source. It combines the long operational lifetime and reliability inherent to LED technology with a high level of brightness suitable for displacing conventional lighting in various applications. The device is packaged for automated assembly processes, offering designers flexibility in integrating solid-state lighting into their products.

1.1 Core Advantages and Target Market

The primary advantages of this component include its high luminous intensity, wide viewing angle, and compatibility with standard infrared (IR) and vapor phase reflow soldering processes. Its EIA-standard package ensures easy integration into existing manufacturing lines. The product is classified as green and is Pb-free, complying with RoHS directives. Target applications are diverse, ranging from automotive and portable lighting (e.g., reading lights, flashlights) to architectural, decorative, and signaling uses (e.g., edge-lit signs, traffic beacons, downlighters).

2. Technical Parameters: In-Depth Objective Interpretation

2.1 Absolute Maximum Ratings

These ratings define the limits beyond which permanent damage to the device may occur. They are not intended for normal operation.

• Power Dissipation (Pd): 120 mW. This is the maximum amount of power the LED package can dissipate as heat without exceeding its thermal limits.
• Peak Forward Current (I_F(PEAK)): 100 mA. This current is permissible only under pulsed conditions (1/10 duty cycle, 0.1ms pulse width) to prevent overheating.
• DC Forward Current (I_F): 30 mA. This is the maximum continuous forward current recommended for reliable long-term operation.
• Reverse Voltage (V_R): 5 V. Exceeding this voltage in reverse bias can cause immediate failure.
• Operating Temperature Range (T_opr): -30°C to +85°C. The device is guaranteed to function within this ambient temperature range.
• Storage Temperature Range (T_stg): -40°C to +100°C.
• Reflow Soldering Condition: Withstands 260°C peak temperature for 10 seconds, compatible with lead-free soldering profiles.

2.2 Electro-Optical Characteristics

These parameters are measured at a standard test condition of 25°C ambient temperature and a forward current (I_F) of 20 mA, which serves as a common reference point.

• Luminous Intensity (I_V): 2200 mcd (Min), 3000 mcd (Typ). This is a measure of the perceived brightness of the LED in a specific direction. The test uses a sensor filtered to match the CIE photopic eye-response curve.
• Viewing Angle (2θ_1/2): 115 degrees (Typ). This is the full angle at which the luminous intensity is half of the intensity at 0 degrees (on-axis). A wide viewing angle indicates a more diffuse light pattern.
• Chromaticity Coordinates (x, y): x=0.295, y=0.282 (Typ). These coordinates define the white point of the LED on the CIE 1931 chromaticity diagram. A tolerance of ±0.01 is applied to these values.
• Forward Voltage (V_F): 2.7 V (Min), 3.4 V (Max) at I_F=20mA. This is the voltage drop across the LED when conducting the specified current. It is a key parameter for driver circuit design.

3. Binning System Explanation

To ensure consistency in mass production, LEDs are sorted into bins based on key parameters. This allows designers to select components that meet specific application requirements for color and brightness uniformity.

3.1 Forward Voltage (V_F) Binning

The VF bin code (V1 to V7) categorizes LEDs based on their forward voltage at 20mA. Each bin has a 0.1V range (e.g., V1: 2.7-2.8V, V7: 3.3-3.4V), with a tolerance of ±0.1V on each bin. This helps in designing stable constant-current drivers.

3.2 Luminous Intensity (I_V) Binning

The IV bin code (S3 to S10) categorizes LEDs based on their luminous intensity at 20mA. Bins range from S3 (2200-2300 mcd) to S10 (2900-3000 mcd). A tolerance of ±10% is applied to the luminous intensity and luminous flux within each bin. The mcd value is for reference.

3.3 Color (Chromaticity) Binning

The color rank table (e.g., A1, C1, D4) defines specific quadrilaterals on the CIE 1931 chromaticity diagram. Each rank has defined corner coordinates for x and y, ensuring the LED's white point falls within a controlled region. A tolerance of ±0.01 is applied to each hue (x, y) bin. This is critical for applications requiring consistent white color appearance across multiple LEDs.

4. Performance Curve Analysis

The datasheet references typical characteristic curves which are essential for understanding device behavior under non-standard conditions. While the specific graphs are not reproduced in the text, their implications are standard.

• I-V Curve: Shows the relationship between forward current and forward voltage. It is non-linear, with a turn-on voltage approximately equal to the V_F at low current. The curve helps in thermal management and driver design.
• Luminous Intensity vs. Forward Current: Typically shows that light output increases with current but may saturate or become less efficient at very high currents due to thermal effects.
• Luminous Intensity vs. Ambient Temperature: Shows that light output generally decreases as the junction temperature increases. This derating is crucial for designing applications that operate in high-temperature environments.
• Viewing Angle Pattern: A polar plot illustrating the spatial distribution of light intensity.

5. Mechanical and Package Information

5.1 Outline Dimensions

The package dimensions are 3.0mm in length, 1.6mm in width, and 1.6mm in height, with a tolerance of ±0.1mm unless otherwise specified. The cathode is typically identified by a marking or a notch on the package. Detailed dimensional drawings should be consulted for precise placement and footprint design.

5.2 Recommended PCB Attachment Pad

A land pattern design is provided for infrared or vapor phase reflow soldering. This pad layout is optimized for reliable solder joint formation, good thermal dissipation, and mechanical stability. Adhering to this recommendation is important for manufacturing yield and long-term reliability.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Parameters

The component is compatible with infrared reflow soldering. A recommended lead-free reflow profile is referenced (per J-STD-020D), with a peak temperature of 260°C sustained for 10 seconds. Following the recommended temperature ramp rates, preheat, and cooling stages is critical to prevent thermal shock and damage to the LED package or phosphor.

6.2 Cleaning

If cleaning is necessary after soldering, only specified chemicals should be used. The LED can be immersed in ethyl alcohol or isopropyl alcohol at normal temperature for less than one minute. Unspecified chemical liquids may damage the epoxy lens or package.

6.3 Storage and Handling

The product is rated Moisture Sensitivity Level (MSL) 3 per JEDEC J-STD-020. Precautions are required to prevent moisture-induced damage during reflow ("popcorning").

• Sealed Package: Store at ≤30°C and ≤90% RH. The shelf life is one year when stored in the original moisture-proof bag with desiccant.
• Opened Package: Store at ≤30°C and ≤60% RH. The components must be subjected to solder reflow within 168 hours (7 days) of exposure to ambient factory conditions. A Humidity Indicator Card should be monitored.
• ESD Precautions: LEDs are sensitive to electrostatic discharge (ESD). Handling with a grounded wrist strap or anti-static gloves is recommended. All equipment and machinery must be properly grounded.

7. Packaging and Ordering Information

7.1 Tape and Reel Specifications

The components are supplied in 12mm wide embossed carrier tape on 7-inch (178mm) diameter reels. Each reel can contain a maximum of 2000 pieces. The packaging conforms to EIA-481-1-B specifications. The tape has cover tape to seal empty pockets, and there is a limit of two consecutive missing components per reel.

7.2 Part Number and Marking

The part number is LTW-010DCG-TR. The luminous flux classification code is marked on each packing bag for traceability and bin identification.

8. Application Suggestions

8.1 Typical Application Circuits

This LED requires a constant current source for optimal operation and longevity. A simple series resistor can be used with a stable voltage supply, calculated as R = (V_supply - V_F) / I_F. For better efficiency and stability over temperature, a dedicated LED driver IC is recommended, especially when driving multiple LEDs in series or parallel. The maximum DC current should not exceed 30mA.

8.2 Thermal Management Design Considerations

Although power dissipation is relatively low (120mW max), proper thermal design is essential to maintain light output and lifespan. The recommended PCB pad aids in heat transfer. For high-current or high-ambient-temperature applications, ensure adequate copper area on the PCB for heat sinking. Operating the LED at lower currents than the maximum can significantly improve efficacy and longevity.

8.3 Optical Design Considerations

The 115-degree viewing angle produces a wide, diffuse beam. For applications requiring a more focused beam, secondary optics such as lenses or reflectors must be used. The chromaticity binning should be considered when multiple LEDs are used side-by-side to avoid visible color differences.

9. Technical Comparison and Differentiation

The LTW-010DCG-TR differentiates itself through its combination of high typical luminous intensity (3000mcd) and a very wide viewing angle (115°). Many competing LEDs offer either high intensity with a narrow beam or a wide beam with lower intensity. This makes it suitable for applications requiring both good overall lumen output and broad illumination coverage without secondary optics. Its compatibility with standard SMD assembly and reflow processes is a key advantage for high-volume manufacturing.

10. Frequently Asked Questions (Based on Technical Parameters)

10.1 What is the difference between luminous intensity (mcd) and luminous flux (lm)?

Luminous intensity measures brightness in a specific direction (candelas), while luminous flux measures the total visible light output in all directions (lumens). This datasheet primarily specifies intensity. The wide viewing angle suggests the total flux is effectively utilized over a broad area.

10.2 Can I drive this LED at 30mA continuously?

Yes, 30mA is the maximum recommended DC forward current. However, for improved reliability and longer life, driving it at a lower current, such as 20mA (the test condition), is advisable. Always consider the ambient temperature and thermal design.

10.3 How do I interpret the color binning table?

The table defines regions on the CIE color chart. To ensure color matching, specify the desired color rank (e.g., C1) when ordering. LEDs from the same rank will have chromaticity coordinates falling within the defined quadrilateral, ensuring visual consistency.

10.4 What happens if I exceed the 5V reverse voltage?

Applying a reverse voltage greater than 5V can cause immediate and catastrophic failure of the LED junction. It is crucial to ensure the circuit design prevents reverse bias conditions, possibly by using a protection diode in parallel if the LED is connected to an AC source or a circuit where reverse voltage is possible.

11. Practical Design and Usage Case

Case: Designing a Portable Task Light
For a battery-powered task light requiring even, wide-area illumination, the LTW-010DCG-TR is an excellent choice. A designer would select LEDs from a tight luminous intensity bin (e.g., S8-S10) and a single color rank (e.g., C2) to ensure uniform brightness and color. They would design a constant-current driver using a boost converter to efficiently drive 3-4 LEDs in series from a 3.7V Li-ion battery, setting the current to 20-25mA for a balance of output and battery life. The wide 115-degree angle eliminates the need for a diffuser, simplifying the mechanical design. The MSL-3 rating mandates planning the assembly process to solder the LEDs within a week of opening the moisture-barrier bag.

12. Operating Principle Introduction

A white LED like the LTW-010DCG-TR typically operates on the principle of phosphor conversion. The core of the device is a semiconductor chip (usually based on indium gallium nitride - InGaN) that emits light in the blue or ultraviolet spectrum when forward biased. This primary light is then directed onto a phosphor layer deposited inside the package. The phosphor absorbs a portion of the primary light and re-emits it as light of longer wavelengths (yellow, red). The mixture of the unconverted blue light and the phosphor-emitted light is perceived by the human eye as white. The exact proportions determine the correlated color temperature (CCT) and chromaticity coordinates.

13. Technology Trends

The solid-state lighting industry continues to evolve with trends focused on increasing efficacy (lumens per watt), improving color rendering index (CRI) for more natural light, and achieving higher reliability and longer lifetimes. There is also a drive toward miniaturization and higher power density. Furthermore, smart lighting integration, featuring tunable white light (adjustable CCT) and connectivity, is becoming more prevalent. Components like the LTW-010DCG-TR represent the mature, cost-effective segment of the market, providing reliable performance for standard lighting applications while these advanced trends develop in higher-end products.