Reverse Mount SMD LED Blue InGaN Datasheet - EIA Package - Voltage 2.8-3.8V - Luminous Intensity 28-180mcd - English Technical Document

1. Product Overview

This document details the specifications for a high-brightness, reverse mount Surface Mount Device (SMD) Light Emitting Diode (LED). The device utilizes an InGaN (Indium Gallium Nitride) semiconductor chip to produce blue light and is housed in a water-clear lens package compliant with EIA (Electronic Industries Alliance) standards. Designed for automated assembly processes, it is compatible with infrared reflow soldering. Key product features include compliance with RoHS directives, classification as a green product, and a high electrostatic discharge (ESD) threshold.

2. In-Depth Technical Parameter Analysis

2.1 Absolute Maximum Ratings

The device's operational limits are defined at an ambient temperature (Ta) of 25°C. Exceeding these ratings may cause permanent damage.

• Power Dissipation (Pd): 76 mW. This is the maximum continuous power the package can dissipate as heat.
• Peak Forward Current (I_FP): 100 mA. This is permissible only under pulsed conditions with a 1/10 duty cycle and a 0.1ms pulse width to prevent overheating.
• Continuous Forward Current (I_F): 20 mA. This is the recommended maximum DC operating current for reliable long-term performance.
• Electrostatic Discharge (ESD) Threshold: 8000 V (Human Body Model). This high rating indicates robust protection against static electricity encountered during handling.
• Operating Temperature Range (T_opr): -20°C to +80°C. The device is functional within this ambient temperature span.
• Storage Temperature Range (T_stg): -30°C to +100°C.
• Infrared Reflow Soldering Condition: Withstands 260°C peak temperature for 10 seconds, suitable for lead-free (Pb-free) assembly processes.

2.2 Electrical and Optical Characteristics

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

• Luminous Intensity (I_V): 28.0 - 180.0 mcd (millicandela). Measured using a sensor filtered to the CIE photopic eye-response curve. The wide range is managed through binning.
• Viewing Angle (2θ_1/2): 130 degrees. This is the full angle at which luminous intensity drops to half its axial (on-axis) value, indicating a wide viewing pattern.
• Peak Emission Wavelength (λ_P): 468 nm. The specific wavelength at which the spectral output is strongest.
• Dominant Wavelength (λ_d): 465.0 - 475.0 nm. This is the single wavelength perceived by the human eye to define the color, derived from the CIE chromaticity diagram.
• Spectral Line Half-Width (Δλ): 25 nm. The bandwidth of the emitted light spectrum at half its maximum intensity (Full Width at Half Maximum - FWHM).
• Forward Voltage (V_F): 2.80 - 3.80 V at I_F=20 mA. The voltage drop across the LED when conducting current.
• Reverse Voltage (V_R): 0.6 - 1.2 V at I_R=20 mA. This is a test condition only; the device is not designed for operation under reverse bias.

3. Binning System Explanation

To ensure color and brightness consistency in production, devices are sorted into bins based on key parameters. The part number typically includes codes specifying its bin.

3.1 Forward Voltage Binning

Units are in Volts (V) measured at 20 mA. Tolerance per bin is ±0.1V.
Bin D7: 2.80 - 3.00V
Bin D8: 3.00 - 3.20V
Bin D9: 3.20 - 3.40V
Bin D10: 3.40 - 3.60V
Bin D11: 3.60 - 3.80V

3.2 Luminous Intensity Binning

Units are in millicandela (mcd) measured at 20 mA. Tolerance per bin is ±15%.
Bin N: 28.0 - 45.0 mcd
Bin P: 45.0 - 71.0 mcd
Bin Q: 71.0 - 112.0 mcd
Bin R: 112.0 - 180.0 mcd

3.3 Dominant Wavelength Binning

Units are in nanometers (nm) measured at 20 mA. Tolerance per bin is ±1nm.
Bin AC: 465.0 - 470.0 nm
Bin AD: 470.0 - 475.0 nm

4. Performance Curve Analysis

The datasheet references typical performance curves which are essential for design. While specific graphs are not reproduced in text, they typically include:

• Relative Luminous Intensity vs. Forward Current (I_V / I_F Curve): Shows how light output increases with current, usually in a non-linear relationship that saturates at higher currents.
• Forward Voltage vs. Forward Current (V_F / I_F Curve): Illustrates the diode's I-V characteristic, crucial for designing current-limiting circuits.
• Relative Luminous Intensity vs. Ambient Temperature: Demonstrates the decrease in light output as the junction temperature rises, a key factor for thermal management.
• Spectral Distribution: A graph showing the relative power emitted across different wavelengths, centered around the peak wavelength of 468 nm with a 25 nm FWHM.

5. Mechanical and Package Information

5.1 Device Dimensions

The LED conforms to a standard EIA package outline. All dimensions are in millimeters with a standard tolerance of ±0.10 mm unless specified otherwise. The package features a reverse mount design, meaning the primary light emission is through the substrate side, which influences the PCB pad layout and optical design.

5.2 Recommended Soldering Pad Layout

A suggested land pattern (footprint) for the PCB is provided to ensure proper soldering, mechanical stability, and thermal relief. Adhering to this pattern is critical for achieving reliable solder joints during reflow.

5.3 Polarity Identification

Like all diodes, the LED has an anode (+) and cathode (-). Correct polarity must be observed during assembly. The datasheet's package drawing indicates the polarity marking on the device, which must be aligned with the corresponding marking on the PCB footprint.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Profile

A suggested infrared (IR) reflow profile for lead-free processes is provided. Key parameters include:
- Pre-heat: 150-200°C.
- Pre-heat Time: Maximum 120 seconds to gradually heat the board and components, activating the flux and minimizing thermal shock.
- Peak Temperature: Maximum 260°C.
- Time Above Liquidus: The profile should ensure the solder paste melts properly. The component can withstand the peak temperature for a maximum of 10 seconds, and reflow should be performed a maximum of two times.

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

6.2 Hand Soldering

If hand soldering is necessary (e.g., for rework), use a soldering iron with a temperature not exceeding 300°C. The soldering time should be limited to a maximum of 3 seconds per joint, and this should be done only once to prevent package damage.

6.3 Storage Conditions

Proper storage is vital to prevent moisture absorption, which can cause \"popcorning\" (package cracking) during reflow.
- Sealed Package: Store at ≤30°C and ≤90% Relative Humidity (RH). Use within one year.
- Opened Package: For components removed from their moisture-proof bag, the storage ambient should not exceed 30°C or 60% RH. It is recommended to complete IR reflow within 672 hours (28 days, MSL 2a).
- Extended Storage (Opened): Store in a sealed container with desiccant or in a nitrogen desiccator.
- Rebaking: If components have been exposed beyond 672 hours, bake at approximately 60°C for at least 20 hours before soldering.

6.4 Cleaning

Do not use unspecified chemicals. If cleaning is required after soldering, immerse the LED in ethyl alcohol or isopropyl alcohol at room temperature for less than one minute. Aggressive solvents may damage the package material or lens.

7. Packaging and Ordering Information

7.1 Tape and Reel Specifications

The device is supplied packaged in 8mm wide embossed carrier tape wound on 7-inch (178mm) diameter reels. This is the standard format for automated pick-and-place machines.
- Pieces per Reel: 3000.
- Minimum Packing Quantity: 500 pieces for remainder quantities.
- Cover Tape: Empty pockets in the carrier tape are sealed with a top cover tape.
- Missing Components: A maximum of two consecutive missing LEDs (empty pockets) is allowed per reel specification.
- Standard: Packaging conforms to ANSI/EIA-481 specifications.

8. Application Notes and Design Considerations

8.1 Intended Use

This LED is designed for ordinary electronic equipment applications, including office equipment, communication devices, and household appliances. It is not rated for safety-critical applications where failure could jeopardize life or health (e.g., aviation, medical life-support, transportation safety systems) without prior consultation and qualification.

8.2 Circuit Design

An external current-limiting resistor or a constant-current driver circuit is mandatory. The forward voltage has a range (2.8-3.8V), so designs should not assume a fixed V_F. The circuit must be designed to limit I_F to 20 mA DC or less under all operating conditions, considering power supply variations and temperature effects.

8.3 Thermal Management

While the package can dissipate 76 mW, effective heat sinking through the PCB pads is essential to maintain low junction temperature. High junction temperature reduces light output (lumen depreciation) and shortens operational lifetime. Ensure the PCB layout provides adequate thermal vias and copper area, especially when operating at high ambient temperatures or near maximum current.

8.4 ESD Precautions

Despite the high 8000V HBM rating, standard ESD handling precautions should always be followed. Use grounded wrist straps, anti-static mats, and properly grounded equipment when handling these devices.

9. Technical Comparison and Differentiation

This device offers several distinct advantages in its category:
1. Reverse Mount Design: Allows for unique optical integration where light is emitted from the side mounted against the PCB, enabling slimmer product designs or specific light guide coupling.
2. High Brightness (Up to 180 mcd): Provides high luminous intensity from a small package, suitable for indicator applications requiring high visibility.
3. Wide Viewing Angle (130°): Offers broad, even illumination ideal for backlighting panels or status indicators viewed from multiple angles.
4. Robust ESD Protection: The 8000V HBM rating exceeds typical industry levels, offering greater handling and application robustness.
5. Lead-Free Reflow Compatibility: Certified for standard Pb-free assembly processes with a 260°C peak temperature rating.

10. Frequently Asked Questions (FAQ)

Q: What is the difference between peak wavelength and dominant wavelength?
A: Peak wavelength (λ_P=468 nm) is the physical point of highest spectral emission. Dominant wavelength (λ_d=465-475 nm) is a calculated value based on human color perception (CIE chart) and is what defines the \"blue\" color you see.

Q: Can I drive this LED with a 3.3V supply without a resistor?
A: No. The forward voltage varies between 2.8V and 3.8V. Connecting directly to 3.3V could result in excessive current if the V_F is lower than 3.3V, potentially destroying the LED. Always use a current-limiting mechanism.

Q: What does \"MSL 2a\" mean in the storage section?
A: Moisture Sensitivity Level (MSL) 2a indicates the component can be exposed to factory floor conditions (≤30°C/60% RH) for 4 weeks (672 hours) before it requires baking prior to reflow soldering.

Q: Is this LED suitable for continuous operation at 20 mA?
A: Yes, 20 mA is the rated continuous DC forward current. However, thermal management via the PCB is crucial to maintain the junction temperature within safe limits for long-term reliability.

11. Design and Usage Case Study

Scenario: Backlighting for a Membrane Switch Panel
A designer needs to backlight a large, curved membrane switch panel with even blue illumination. The reverse mount design of this LED is ideal. The LEDs are placed on the flexible PCB (flex circuit) with the emitting surface facing down towards a light guide layer. The 130-degree viewing angle ensures light spreads evenly across the guide. The designer selects bins from the upper luminous intensity range (e.g., Bin Q or R) to achieve the required brightness and specifies a tight dominant wavelength bin (e.g., AC or AD) for color consistency across the panel. The automated tape-and-reel packaging allows for fast, reliable placement by the assembly machine. The high ESD rating provides protection during the handling of the flex circuit.

12. Technology Principle Introduction

This LED is based on InGaN semiconductor technology. In a Light Emitting Diode, light is produced through a process called electroluminescence. When a forward voltage is applied across the p-n junction of the semiconductor (InGaN), electrons from the n-type region and holes from the p-type region are injected into the active region. When these electrons and holes recombine, they release energy in the form of photons (light). The specific wavelength (color) of the light is determined by the bandgap energy of the semiconductor material. InGaN has a bandgap suitable for producing light in the blue and green regions of the spectrum. The \"water clear\" lens is typically made of epoxy or silicone and is designed to efficiently extract the light generated inside the semiconductor chip.

13. Industry Trends and Developments

The SMD LED market continues to evolve towards higher efficiency, smaller packages, and greater integration. Trends relevant to this type of device include:
1. Increased Efficiency (lm/W): Ongoing improvements in epitaxial growth and chip design yield more light output per unit of electrical power, reducing energy consumption and thermal load.
2. Miniaturization: The drive for smaller end-products pushes for LEDs in ever-smaller package footprints while maintaining or increasing light output.
3. Improved Color Consistency: Advances in manufacturing control and more granular binning strategies allow for tighter color tolerances in production runs, important for multi-LED arrays.
4. Enhanced Reliability: Improvements in package materials (e.g., high-temperature silicones) and die attach technologies lead to longer operational lifetimes and better performance under harsh environmental conditions.
5. Smart Integration: While this is a discrete component, the broader trend is towards integrated modules that combine LEDs with drivers, controllers, and sensors in a single package.