SMD LED LTSA-S020ZGWTA Datasheet - 2.0x1.25x0.8mm - 2.9V - 90mW - Green Diffused - English Technical Document

1. Product Overview

This document details the specifications for a surface-mount device (SMD) LED designed for automated printed circuit board assembly and space-constrained applications. The component features a diffused lens and emits green light, making it suitable for a variety of electronic equipment where indicator or lighting functions are required.

1.1 Key Features

• Compliant with RoHS environmental standards.
• Packaged on 12mm tape wound onto 7-inch diameter reels for automated assembly.
• Preconditioned to JEDEC Moisture Sensitivity Level 2a.
• Qualification referenced to AEC-Q101 Rev D, suitable for automotive applications.
• Standard EIA package outline for compatibility.
• IC compatible drive current.
• Designed for compatibility with automatic pick-and-place equipment.
• Suitable for infrared reflow soldering processes.

1.2 Target Applications

This LED is intended for use in a wide range of electronic equipment, including but not limited to cordless and cellular phones, notebook computers, and network systems. Specific mention is made for accessory applications in engineering vehicles.

2. Technical Specifications Deep Dive

2.1 Absolute Maximum Ratings

All ratings are specified at an ambient temperature (Ta) of 25°C. Exceeding these limits may cause permanent damage.

• Power Dissipation (Pd): 90 mW
• Peak Forward Current (I_F(peak)): 50 mA (at 1/10 duty cycle, 0.1ms pulse width)
• Continuous Forward Current (I_F): 20 mA DC
• Operating Temperature Range: -40°C to +100°C
• Storage Temperature Range: -40°C to +100°C

2.2 Electrical and Optical Characteristics

Typical performance is measured at Ta=25°C under the specified test conditions.

• Luminous Intensity (I_V): 250 - 640 mcd (Typical value at I_F = 2 mA). Measured with a sensor/filter approximating the CIE photopic eye-response curve.
• Viewing Angle (2θ_1/2): 110 degrees. Defined as the off-axis angle where intensity is half the axial value.
• Peak Emission Wavelength (λ_p): 518 nm (from spectral measurement).
• Dominant Wavelength (λ_d): 523 - 538 nm (at I_F = 2 mA). Represents the perceived color. Tolerance is ±1 nm.
• Spectral Line Half-Width (Δλ): 35 nm.
• Forward Voltage (V_F): 2.0 - 2.9 V (at I_F = 2 mA). Tolerance is ±0.1 V.
• Reverse Voltage (V_z): 6 - 8 V (at I_z = 10 μA). Note: The device is not designed for reverse operation; this parameter is for IR test only.
• Reverse Current (I_R): 10 μA maximum (at V_R = 5V).
• ESD Withstand Voltage: 2000 V (Human Body Model).

3. Binning System Explanation

To ensure color and brightness consistency, components are sorted into bins based on key parameters. The batch label indicates the bin codes for V_f, I_V, and Color (W_d).

3.1 Forward Voltage (V_f) Binning

Measured at I_F = 2 mA. Tolerance within each bin is ±0.1V.

• H3: 2.0 V (Min) to 2.3 V (Max)
• H4: 2.3 V (Min) to 2.6 V (Max)
• H5: 2.6 V (Min) to 2.9 V (Max)

3.2 Luminous Intensity (I_V) Binning

Measured at I_F = 2 mA. Tolerance within each bin is ±11%.

• T1: 250 mcd (Min) to 400 mcd (Max)
• T2: 400 mcd (Min) to 640 mcd (Max)

3.3 Dominant Wavelength (W_d) Binning

Measured at I_F = 2 mA. Tolerance within each bin is ±1 nm.

• AQ: 523 nm (Min) to 528 nm (Max)
• AR: 528 nm (Min) to 533 nm (Max)
• AS: 533 nm (Min) to 538 nm (Max)

4. Performance Curve Analysis

The datasheet includes typical characteristic curves to aid in design. These curves illustrate the relationship between forward current and luminous intensity, as well as the spatial distribution of light (radiation pattern). The spatial distribution plot is crucial for understanding the illumination profile created by the diffused lens, showing how light is dispersed over the 110-degree viewing angle. Designers can use the I_V vs. I_F curve to estimate brightness at different drive currents, ensuring the LED meets application requirements without exceeding maximum ratings.

5. Mechanical and Package Information

5.1 Package Dimensions

The LED conforms to a standard SMD package outline. Key dimensions (in millimeters) include a body size of approximately 2.0 x 1.25 mm with a height of 0.8 mm. Tolerances are typically ±0.2 mm unless otherwise specified. A detailed dimensional drawing should be referenced for exact land pattern design.

5.2 Recommended PCB Pad Design

A land pattern recommendation is provided for infrared or vapor phase reflow soldering. Adhering to this pattern is critical for achieving proper solder joint formation, ensuring mechanical stability, and facilitating heat dissipation during operation.

6. Soldering and Assembly Guidelines

6.1 IR Reflow Soldering Profile

For lead-free (Pb-free) soldering processes, the recommended profile follows J-STD-020. Key parameters include:

• Pre-heat Temperature: 150°C to 200°C.
• Pre-heat Time: Maximum 120 seconds.
• Peak Temperature: Maximum 260°C.
• Time Above Liquidus: Maximum 10 seconds (recommended for a maximum of two reflow cycles).

Note: The optimal profile depends on the specific PCB design, components, solder paste, and oven. Characterization for the specific assembly is advised.

6.2 Hand Soldering

If hand soldering is necessary:

• Iron Temperature: Maximum 300°C.
• Soldering Time: Maximum 3 seconds per lead (one time only).

6.3 Cleaning

If cleaning is required after soldering, use alcohol-based solvents like ethyl alcohol or isopropyl alcohol at room temperature. Immersion should not exceed one minute. Avoid unspecified chemical cleaners.

7. Storage and Handling Cautions

7.1 Storage Conditions

• Sealed Package: Store at ≤30°C and ≤70% RH. Use within one year of packing date when in moisture-proof bags with desiccant.
• Opened Package: Store at ≤30°C and ≤60% RH. Components should be reflow-soldered within 168 hours (7 days) of exposure.
• Extended Storage (Opened): Store in a sealed container with desiccant or in a nitrogen desiccator.
• Baking: If exposed for more than 168 hours, bake at approximately 60°C for at least 48 hours before soldering to remove moisture and prevent "popcorning" during reflow.

7.2 Application Caution

This LED is designed for ordinary electronic equipment. It is not recommended for safety-critical applications where failure could jeopardize life or health (e.g., aviation, medical life-support) without prior consultation and specific qualification.

8. Packaging and Ordering Information

8.1 Tape and Reel Specifications

• Tape Width: 12 mm.
• Reel Diameter: 7 inches.
• Quantity per Reel: 2000 pieces.
• Minimum Order Quantity: 500 pieces for remainder lots.
• Packing Standard: In accordance with EIA-481-1-B. Empty pockets are sealed with cover tape. A maximum of two consecutive missing components is allowed.

9. Application Suggestions and Design Considerations

When integrating this LED into a design, consider the following:

• Current Limiting: Always use a series resistor or constant current driver to limit the forward current to a safe value, typically at or below the 20 mA DC maximum. The V_F bin should be considered for accurate resistor calculation.
• Thermal Management: While the power dissipation is low (90 mW), ensure the PCB provides adequate thermal relief, especially if operating at high ambient temperatures or near the maximum current.
• Optical Design: The diffused lens provides a wide, even viewing angle suitable for panel indicators. For focused light, secondary optics may be required.
• ESD Protection: Although rated for 2kV HBM, implement standard ESD handling and, if necessary, circuit protection (e.g., TVS diodes) in sensitive environments.

10. Technical Comparison and Differentiation

This LED differentiates itself through its combination of features: AEC-Q101 qualification reference makes it a candidate for automotive accessory applications. The preconditioning to MSL 2a enhances reliability for standard reflow processes. The detailed binning system allows for tighter color and brightness matching in production runs compared to non-binned parts. The wide 110-degree viewing angle with a diffused lens is ideal for applications requiring broad, non-glare illumination.

11. Frequently Asked Questions (Based on Technical Parameters)

Q: What is the difference between Peak Wavelength and Dominant Wavelength?
A: Peak Wavelength (518 nm) is the point of maximum power output in the spectral curve. Dominant Wavelength (523-538 nm) is derived from the CIE color chart and represents the single wavelength that best matches the perceived color of the light, which is more relevant for human vision.

Q: Can I drive this LED at 20 mA continuously?
A: Yes, 20 mA is the maximum continuous DC forward current rating at 25°C. For reliable operation, especially at higher ambient temperatures, derating the current is recommended. Always refer to the power dissipation limit (90 mW).

Q: Why is there a reverse voltage rating if the device is not for reverse operation?
A: The V_z rating (6-8V) is primarily a test parameter for internal quality assurance (IR test). It indicates the breakdown voltage. In circuit design, you should ensure the LED is never subjected to a reverse bias, as even small reverse currents can degrade performance.

Q: How do I interpret the bin code "H4/T2/AR" on a label?
A> This indicates a specific batch where the LEDs have a forward voltage between 2.3V and 2.6V (H4), a luminous intensity between 400 and 640 mcd (T2), and a dominant wavelength between 528 and 533 nm (AR).

12. Practical Design and Usage Case

Scenario: Designing a status indicator for a consumer router. The LED needs to be green, visible from various angles, and reliable for continuous operation. This component is suitable. A drive current of 5-10 mA would provide ample brightness while staying well within limits, ensuring long-term reliability. The designer would select a current-limiting resistor based on the typical V_F (e.g., 2.5V for H4 bin) and the supply voltage (e.g., 3.3V). The wide viewing angle ensures the status is visible regardless of the router's orientation. The tape-and-reel packaging allows for efficient, automated assembly on the router's main PCB.

13. Principle of Operation

This is a semiconductor light-emitting diode (LED). When a forward voltage exceeding its threshold is applied, electrons and holes recombine in the active region (composed of InGaN for green emission), releasing energy in the form of photons (light). The specific material composition determines the wavelength (color) of the emitted light. The diffused epoxy lens encapsulates the semiconductor die, providing environmental protection, mechanical support, and shaping the light output into a wide, uniform beam.

14. Technology Trends

The optoelectronics industry continues to advance in several key areas relevant to such components: increased luminous efficacy (more light output per watt), improved color consistency and tighter binning tolerances, enhanced reliability and higher temperature operation for automotive and industrial markets, and further miniaturization of packages. The drive towards higher efficiency and broader adoption of LEDs in general lighting and automotive applications pushes continuous improvement in semiconductor materials and packaging technologies.