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

1. Product Overview

This document details the specifications of a high-brightness, reverse-mount Surface Mount Device (SMD) Light Emitting Diode (LED). The device utilizes an Indium Gallium Nitride (InGaN) semiconductor chip to generate blue light, encapsulated within a transparent lens compliant with the Electronic Industries Alliance (EIA) standard. It is designed for automated assembly processes and is compatible with infrared reflow soldering. Key product features include compliance with the RoHS directive, classification as a green product, and a high Electrostatic Discharge (ESD) threshold.

2. In-depth Technical Parameter Analysis

2.1 Absolute Maximum Ratings

The operating limits of the device are defined under the condition of an ambient temperature (Ta) of 25°C. Exceeding these ratings may cause permanent damage.

• Power Dissipation (Pd):76 mW. This is the maximum power that the package can continuously dissipate in the form of heat.
• Peak Forward Current (I_FP):100 mA. This current is only allowed under pulse conditions with a duty cycle of 1/10 and a pulse width of 0.1 ms to prevent overheating.
• Continuous Forward Current (I_F):20 mA. This is the maximum recommended DC operating current to ensure long-term reliable performance.
• Electrostatic Discharge (ESD) Threshold:8000 V (Human Body Model). This high rating indicates the device has robust protection against electrostatic discharge during handling.
• Operating Temperature Range (T_opr):-20°C to +80°C. The device can operate normally within this ambient temperature range.
• Storage temperature range (T_stg):-30°C to +100°C.
• Infrared reflow soldering conditions:Withstands peak temperature of 260°C for up to 10 seconds, suitable for Pb-free assembly process.

2.2 Electrical and Optical Characteristics

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

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

3. Bin System Description

To ensure color and brightness consistency in production, devices are sorted into different bins based on key parameters. The part number typically includes a code that designates its bin.

3.1 Forward Voltage Binning

Unit is Volt (V), measured at 20 mA. Tolerance per bin is ±0.1V.
Bin D7: 2.80 - 3.00V
Gear D8: 3.00 - 3.20V
Gear D9: 3.20 - 3.40V
Gear D10: 3.40 - 3.60V
Gear D11: 3.60 - 3.80V

3.2 Luminous Intensity Binning

Unit is millicandela (mcd), measured at 20 mA. Each bin tolerance is ±15%.
Bin N: 28.0 - 45.0 mcd
Bin P: 45.0 - 71.0 mcd
Bin Q: 71.0 - 112.0 mcd
Gear R: 112.0 - 180.0 mcd

3.3 Dominant Wavelength Binning

Unit is nanometer (nm), measured at 20 mA. Tolerance per grade is ±1nm.
Gear AC: 465.0 - 470.0 nm
Gear AD: 470.0 - 475.0 nm

4. Performance Curve Analysis

The datasheet references typical performance curves that are crucial for design. Although the specific charts are not reproduced in the text, they typically include:

• Relative luminous intensity vs. forward current (I_V/ I_Fcurve):Shows how the light output increases with current, typically in a nonlinear relationship, tending to saturate at higher currents.
• Forward voltage vs. forward current (V_F/ I_Fcurve):Demonstrating the I-V characteristics of a diode is crucial for designing current-limiting circuits.
• Relative luminous intensity vs. ambient temperature:Demonstrating how light output decreases with increasing junction temperature is a key factor in thermal management.
• Spectral distribution:A chart displaying relative power distribution across different wavelengths, centered at a peak wavelength of 468 nm with a full width at half maximum of 25 nm.

5. Mechanical and Packaging Information

5.1 Device Dimensions

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

5.2 Recommended Solder Pad Layout

Provides recommended PCB land pattern (package dimensions) to ensure proper soldering, mechanical stability, and thermal dissipation. Adhering to this pattern is critical for achieving reliable solder joints during the reflow process.

5.3 Polarity Marking

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

6. Soldering and Assembly Guide

6.1 Reflow Soldering Profile

Provided recommended infrared (IR) reflow profile for lead-free process. Key parameters include:
- Preheat:150-200°C.
- Preheat time:Maximum 120 seconds, to gradually heat the circuit board and components, activate the flux and minimize thermal shock.
- Peak temperature:Maximum 260°C.
- Time above liquidus:The profile should ensure proper solder paste melting. Components can withstand peak temperature for a maximum of 10 seconds, and reflow should be performed no more than twice.

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

6.2 Manual Soldering

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

6.3 Storage Conditions

Proper storage is crucial to prevent moisture absorption, which can lead to "popcorn" phenomenon (package cracking) during reflow soldering.
- Sealed Packaging:Store at ≤30°C and ≤90% relative humidity (RH). Use within one year.
- Opened package:For components removed from the moisture barrier bag, the storage environment should not exceed 30°C or 60% RH. It is recommended to complete infrared reflow soldering within 672 hours (28 days, MSL 2a).
- Long-term storage (opened):Store in a sealed container with desiccant or in a nitrogen dry box.
- Rebake:If components are exposed for more than 672 hours, bake at approximately 60°C for at least 20 hours prior to soldering.

6.4 Cleaning

Do not use unspecified chemicals. If cleaning is required after soldering, immerse the LED in ethanol or isopropyl alcohol at room temperature for no more than one minute. Strong solvents may damage the packaging material or lens.

7. Packaging and Ordering Information

7.1 Tape and Reel Specifications

The device is supplied in 8mm wide, embossed carrier tape wound on 7-inch (178mm) diameter reels. This is the standard format for automated placement equipment.
- Quantity per reel: 3000.
- Minimum package quantity:Minimum remaining quantity is 500 pieces.
- Cover Tape:Empty positions on the carrier tape are sealed with top cover tape.
- Missing Component:According to the reel specification, a maximum of two consecutive missing LEDs (empty positions) is allowed.
- Standard:Packaging complies with ANSI/EIA-481 specification.

8. Application Description and Design Considerations

8.1 Intended Use

This LED is designed for general electronic equipment applications, including office equipment, communication equipment, and household appliances. It is not suitable for safety-critical applications where failure could endanger life or health (e.g., aviation, medical life support, traffic safety systems) without prior consultation and certification.

8.2 Circuit Design

An external current-limiting resistor or constant-current drive circuit must be used. The forward voltage has a range (2.8-3.8V), so the design should not assume a fixed V._FThe circuit must be designed to limit I_Fto 20 mA DC or less under all operating conditions (considering power supply variations and temperature effects).

8.3 Thermal Management

Although the package can dissipate 76 mW, effective heat dissipation through the PCB pads is crucial for maintaining a low junction temperature. High junction temperature reduces light output (luminous decay) and shortens operational lifespan. Ensure the PCB layout provides sufficient thermal vias and copper area, especially when operating in high ambient temperatures or near maximum current.

8.4 ESD Precautions

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

9. Technical Comparison and Differentiation

This device offers several significant advantages within its category:
1. Reverse Mount Design:It enables unique optical integration, with light emitted from the side mounted on the PCB, allowing for 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°):Provides broad, uniform illumination, ideal for backlight panels or status indicators viewed from multiple angles.
4. Robust ESD protection:Ƙimar HBM na 8000V ya wuce matakin masana'antu na yau da kullun, yana ba da ƙarfi mai ƙarfi da ƙarfin aikace-aikace.
5. Haɗin kai da sake kwarara mara gubar:Certified for peak temperature rating of 260°C, suitable for standard lead-free assembly processes.

10. Frequently Asked Questions (FAQ)

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

Q: Can I drive this LED with a 3.3V power supply without a resistor?
A: No. The forward voltage varies between 2.8V and 3.8V. If V_Fis below 3.3V, directly connecting it to 3.3V may cause excessive current, potentially damaging the LED. A current-limiting mechanism must be used.

Q: What does "MSL 2a" mean in the storage section?
A: Moisture Sensitivity Level (MSL) 2a indicates that 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 to ensure long-term reliability.

11. Design and Use Case Studies

Scenario: Membrane Switch Panel Backlighting
The designer needs to provide uniform blue backlighting for a large curved membrane switch panel. The reverse mounting design of this LED is ideal. The LED is placed on a flexible PCB (flex board) with the light-emitting surface facing down towards the light guide layer. The 130-degree viewing angle ensures uniform light diffusion within the light guide layer. The designer selects bins from the higher luminous intensity range (e.g., Q-bin or R-bin) to achieve the required brightness and specifies strict dominant wavelength bins (e.g., AC or AD) to ensure color consistency across the entire panel. Automated tape and reel packaging facilitates fast and reliable placement by pick-and-place machines. The high ESD rating provides protection during flexible circuit handling.

12. Introduction to Technical Principles

Wannan LED ya dogara ne akan fasahar semiconductor na InGaN. A cikin diode mai haskakawa, ana samar da haske ta hanyar aikin da ake kira electroluminescence. Lokacin da aka sanya ƙarfin lantarki mai kyau akan mahaɗin p-n na semiconductor (InGaN), electrons daga yankin n-type da kuma ramuka daga yankin p-type ana shigar da su cikin yankin mai aiki. Sa’ad da waɗannan electrons da ramuka suka haɗu, suna sakin makamashi a cikin nau’in photon (haske). Takamaiman tsawon raƙuman haske (launi) ana ƙaddara shi ta hanyar makamashin tazarar band na kayan semiconductor. Tazarar band na InGaN ta dace don samar da haske a cikin yankuna shuɗi da kore na bakan haske. "Ruwan tabarau" na bayyane yawanci ana yin su da epoxy ko silicone, an tsara su don fitar da hasken da aka samar a cikin guntu na semiconductor yadda ya kamata.

13. Industry Trends and Development

Kasuwar SMD LED na ci gaba da tafiya zuwa mafi inganci, ƙaramin kunshewa da mafi girman haɗin kai. Trends masu alaƙa da irin waɗannan na'urori sun haɗa da:
1. Efficiency Improvement (lm/W):Continuous improvements in epitaxial growth and chip design enable more light output per unit of electrical power, thereby reducing energy consumption and thermal load.
2. Miniaturization:The demand for smaller end products drives the continuous reduction in LED package size while maintaining or increasing light output.
3. Color Consistency Improvement:Advances in manufacturing control and finer binning strategies result in smaller color tolerances within production batches, which is crucial for multi-LED arrays.
4. Reliability Enhancement:Improvements in encapsulation materials (e.g., high-temperature silicone) and die-attach technology have led to longer operational lifespans and better performance under harsh environmental conditions.
5. Intelligent Integration:Although this is a discrete component, the broader trend is toward integrated modules that combine the LED with drivers, controllers, and sensors in a single package.