SMD LED LTST-010TBKT Datasheet - Blue InGaN - 20mA - 80mW - English Technical Document

1. Product Overview

This document provides the complete technical specifications for a surface-mount device (SMD) Light Emitting Diode (LED). The component is designed for automated printed circuit board (PCB) assembly processes and is suitable for space-constrained applications. Its miniature size and compatibility with standard industry processes make it a versatile choice for modern electronics.

1.1 Features

• Compliant with RoHS (Restriction of Hazardous Substances) directives.
• Packaged in 12mm tape on 7-inch diameter reels for automated handling.
• Standard EIA (Electronic Industries Alliance) package footprint.
• Input/output compatible with integrated circuit (IC) logic levels.
• Designed for compatibility with automatic pick-and-place equipment.
• Suitable for infrared (IR) reflow soldering processes.
• Preconditioned to accelerate to JEDEC (Joint Electron Device Engineering Council) moisture sensitivity Level 3.

1.2 Applications

This LED is intended for use in a broad range of electronic equipment, including but not limited to:

• Telecommunication devices (e.g., cordless phones, cellular phones).
• Office automation equipment and notebook computers.
• Home appliances and consumer electronics.
• Network systems and industrial control equipment.
• Status and power indicators.
• Backlighting for front panels and keypads.
• Signal lighting and symbolic luminaries.
• Indoor signboards and general decorative lighting.

2. Package Dimensions

The device features a standard surface-mount package. Critical dimensions are provided in technical drawings within the source document. All primary dimensions are specified in millimeters (mm). The standard tolerance for these dimensions is ±0.1 mm (±0.004 inches) unless explicitly stated otherwise in the drawing notes. The lens is water clear, and the light source color is blue, utilizing an Indium Gallium Nitride (InGaN) semiconductor material.

3. Ratings and Characteristics

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

3.1 Absolute Maximum Ratings

• Power Dissipation (Pd): 80 mW
• Peak Forward Current (I_F(peak)): 100 mA (at 1/10 duty cycle, 0.1ms pulse width)
• Continuous Forward Current (I_F): 20 mA DC
• Operating Temperature Range: -40°C to +85°C
• Storage Temperature Range: -40°C to +100°C

3.2 Suggested IR Reflow Profile

For lead-free (Pb-free) soldering processes, a reflow profile compliant with J-STD-020B is recommended. The profile typically includes a pre-heat stage, a thermal soak, a reflow zone with a peak temperature, and a cooling phase. The maximum peak temperature should not exceed 260°C, and the time above 217°C should be limited as per the standard to prevent thermal damage to the LED package and internal die.

3.3 Electrical & Optical Characteristics

Typical performance parameters measured at Ta=25°C and I_F=20mA, unless otherwise noted.

• Luminous Intensity (I_V): 90.0 - 224.0 mcd (millicandela). Measured with a filter approximating the CIE photopic eye-response curve.
• Viewing Angle (2θ_1/2): 110 degrees (typical). Defined as the full angle at which intensity is half the axial (on-axis) value.
• Peak Emission Wavelength (λ_p): 468 nm (typical).
• Dominant Wavelength (λ_d): 465 - 475 nm. Derived from CIE chromaticity coordinates.
• Spectral Line Half-Width (Δλ): 35 nm (typical). The width of the emission spectrum at half its maximum intensity.
• Forward Voltage (V_F): 2.8 - 3.8 V.
• Reverse Current (I_R): 10 μA (maximum) at a reverse voltage (V_R) of 5V. The device is not designed for operation under reverse bias.

3.4 Measurement Notes

1. Luminous intensity measurement follows CIE standards for photopic vision.
2. Dominant wavelength tolerance is ±1 nm.
3. Forward voltage tolerance for a given bin is ±0.1 V.
4. The reverse voltage test is for informational/quality purposes only; the LED is a forward-biased device.

4. Bin Rank System

Components are sorted (binned) according to key parameters to ensure consistency in application. The following bin codes define the guaranteed ranges for each parameter.

4.1 Forward Voltage (V_F) Rank

Binned at I_F = 20mA. Tolerance per bin is ±0.1V.
Bin Codes: D7 (2.8-3.0V), D8 (3.0-3.2V), D9 (3.2-3.4V), D10 (3.4-3.6V), D11 (3.6-3.8V).

4.2 Luminous Intensity (I_V) Rank

Binned at I_F = 20mA. Tolerance per bin is ±11%.
Bin Codes: Q2 (90.0-112.0 mcd), R1 (112.0-140.0 mcd), R2 (140.0-180.0 mcd), S1 (180.0-224.0 mcd).

4.3 Dominant Wavelength (λ_d) Rank

Binned at I_F = 20mA. Tolerance per bin is ±1nm.
Bin Codes: AC (465.0-470.0 nm), AD (470.0-475.0 nm).

5. Typical Performance Curves

The source document includes graphical representations of key characteristics as a function of various parameters. These curves are essential for detailed design analysis.

• Relative Luminous Intensity vs. Forward Current: Shows how light output increases with drive current, typically in a sub-linear manner at higher currents due to heating and efficiency droop.
• Relative Luminous Intensity vs. Ambient Temperature: Demonstrates the thermal quenching effect, where light output decreases as the junction temperature rises.
• Forward Voltage vs. Forward Current: Illustrates the diode's I-V characteristic, showing the turn-on voltage and dynamic resistance.
• Forward Voltage vs. Ambient Temperature: Shows the negative temperature coefficient of the forward voltage, a useful property for temperature sensing.
• Spectral Distribution: A plot of relative radiant power versus wavelength, centered around the peak wavelength of 468 nm with a typical half-width of 35 nm.
• Viewing Angle Pattern: A polar plot depicting the spatial distribution of luminous intensity, confirming the 110-degree viewing angle.

6. User Guide & Handling

6.1 Cleaning

Only specified cleaning agents should be used. Unspecified chemicals may damage the LED package epoxy. If cleaning is necessary, immersion in ethyl alcohol or isopropyl alcohol at room temperature for less than one minute is acceptable. Agitation or ultrasonic cleaning should be avoided unless specifically qualified.

6.2 Recommended PCB Pad Layout

A land pattern (footprint) design is provided for the PCB. This pattern is optimized for reliable soldering using infrared or vapor phase reflow processes. Adhering to this recommended pad geometry ensures proper solder joint formation, self-alignment during reflow, and mechanical stability.

6.3 Tape and Reel Packaging

The LEDs are supplied in embossed carrier tape with a protective cover tape. Detailed dimensions for the tape pockets, pitch, and overall tape width are specified. The components are wound onto 7-inch (178 mm) diameter reels. Standard reel quantities are 4000 pieces per full reel, with a minimum packing quantity of 500 pieces for partial reels. The packaging conforms to ANSI/EIA-481 specifications.

7. Cautions and Application Notes

7.1 Intended Application

These LEDs are designed for use in standard commercial and consumer electronic equipment. They are not rated or intended for safety-critical applications where failure could lead to direct risk to life or health, such as in aviation, medical life-support, or transportation control systems. For such applications, components with appropriate reliability certifications must be selected.

7.2 Storage Conditions

Sealed Package: Store at ≤30°C and ≤70% Relative Humidity (RH). The shelf life in the sealed moisture barrier bag with desiccant is one year.
Opened Package: For components removed from the sealed bag, the storage environment must not exceed 30°C and 60% RH. Components should be subjected to IR reflow soldering within 168 hours (7 days) of exposure to this environment (MSL Level 3). For longer exposure, store in a sealed container with desiccant or in a nitrogen atmosphere. Components exposed for more than 168 hours require a baking process (e.g., 60°C for 48 hours) prior to soldering to remove absorbed moisture and prevent \"popcorning\" damage during reflow.

7.3 Soldering Recommendations

Reflow Soldering (Recommended):
- Pre-heat Temperature: 150-200°C
- Pre-heat Time: Maximum 120 seconds
- Peak Temperature: Maximum 260°C
- Time at Peak/Soldering Time: Maximum 10 seconds (maximum of two reflow cycles allowed)
Hand Soldering (If necessary):
- Iron Temperature: Maximum 300°C
- Soldering Time per lead: Maximum 3 seconds (one-time operation only)

Important Note: The optimal reflow profile depends on the specific PCB design, component density, solder paste, and oven. The provided parameters are guidelines. Board-level characterization is recommended to achieve reliable solder joints without thermally stressing the LED.

7.4 Drive Method

An LED is a current-controlled device. To ensure consistent and stable luminous intensity, it must be driven by a controlled current source, not a voltage source. A simple series current-limiting resistor is the most common method when powered from a voltage rail. The resistor value is calculated using Ohm's Law: R = (V_supply - V_F) / I_F. For precision applications or to maintain constant brightness over temperature and supply voltage variations, a constant current driver circuit (linear or switching) is recommended. Driving the LED with a stable current within its specified limits (e.g., 20mA DC) is crucial for achieving the desired light output, color, and long-term reliability.

8. Design Considerations and Application Suggestions

8.1 Thermal Management

While the power dissipation is relatively low (80mW max), effective thermal management is still important for longevity and stable performance. The LED's luminous intensity decreases with increasing junction temperature (thermal quenching). Ensure the PCB has adequate thermal relief, especially if driving at or near the maximum continuous current. Avoid placing the LED near other significant heat sources on the board.

8.2 Optical Design

The 110-degree viewing angle provides a wide, diffuse emission pattern suitable for status indicators and backlighting. For applications requiring a more focused beam, secondary optics (lenses or reflectors) must be employed. The water-clear lens is optimal for true color emission. When designing light guides or diffusers for backlighting, the spatial intensity distribution (viewing angle pattern) should be considered to achieve uniform illumination.

8.3 Electrical Design

Account for the forward voltage binning in your design. The circuit must function correctly across the entire V_F range (2.8V to 3.8V). If using a simple resistor, size it for the highest V_F in your selected bin to guarantee the minimum required current. For parallel strings of LEDs, consider using individual current-limiting resistors per string to compensate for V_F variations and prevent current hogging. Always include protection against reverse voltage connection and voltage transients on the power line, as the LED has a low maximum reverse voltage rating.

8.4 Manufacturing and Assembly

Leverage the component's compatibility with automated assembly. The tape-and-reel packaging is designed for high-speed pick-and-place machines. Follow the recommended IR reflow profile and PCB pad layout precisely to ensure high first-pass yield and reliability. Adhere strictly to the moisture sensitivity level (MSL 3) handling procedures to prevent moisture-induced package cracking during soldering.