Reverse Mount SMD Blue LED Datasheet - 2.0x1.25x0.8mm - Voltage 2.8-3.8V - Power 76mW - English Technical Document

1. Product Overview

This document details the specifications for a high-brightness, reverse mount surface-mount device (SMD) blue LED. The component utilizes an InGaN (Indium Gallium Nitride) chip, which is known for producing efficient and bright blue light emission. Designed for automated assembly processes, it is packaged on 8mm tape wound onto 7-inch reels, facilitating high-volume production. The LED is compliant with RoHS (Restriction of Hazardous Substances) directives, classifying it as a green product suitable for modern electronic manufacturing.

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. The maximum continuous forward current (DC) is 20 mA. A higher peak forward current of 100 mA is permissible under pulsed conditions with a 1/10 duty cycle and a 0.1ms pulse width. The maximum power dissipation is 76 mW. The operating temperature range is from -20°C to +80°C, while the storage temperature range extends from -30°C to +100°C. For soldering, it can withstand infrared reflow at 260°C for a maximum of 10 seconds.

2.2 Electrical and Optical Characteristics

Key performance parameters are measured at Ta=25°C and a forward current (IF) of 20 mA, unless otherwise specified.

• Luminous Intensity (IV): Ranges from a minimum of 28.0 mcd to a maximum of 180.0 mcd. The typical value is not specified, indicating a wide binning range.
• Viewing Angle (2θ1/2): A wide viewing angle of 130 degrees, defined as the off-axis angle where intensity is half the axial value.
• Peak Emission Wavelength (λP): Typically 468 nm.
• Dominant Wavelength (λd): Ranges from 465.0 nm to 475.0 nm, defining the perceived color.
• Spectral Line Half-Width (Δλ): Approximately 25 nm, indicating the spectral purity of the blue light.
• Forward Voltage (VF): Ranges from 2.80 V to 3.80 V at 20 mA.
• Reverse Current (IR): Maximum of 10 μA when a reverse voltage (VR) of 5V is applied. The device is not designed for reverse bias operation.

Important notes clarify measurement conditions: luminous intensity uses a CIE eye-response filter, and caution against Electrostatic Discharge (ESD) is emphasized, recommending proper grounding and handling procedures.

3. Binning System Explanation

The product is categorized into bins based on key parameters to ensure consistency in application. Three separate binning dimensions are provided:

3.1 Forward Voltage Binning

Bins are labeled D7 through D11, each covering a 0.2V range from 2.80V to 3.80V, with a tolerance of ±0.1V per bin.

3.2 Luminous Intensity Binning

Bins are labeled N, P, Q, and R. Intensity ranges from 28-45 mcd (N) up to 112-180 mcd (R), with a tolerance of ±15% per bin.

3.3 Dominant Wavelength Binning

Bins are labeled AC (465.0-470.0 nm) and AD (470.0-475.0 nm), with a tight tolerance of ±1 nm per bin.

This multi-dimensional binning allows designers to select LEDs that match specific voltage, brightness, and color requirements for their circuits.

4. Performance Curve Analysis

The datasheet references typical electrical and optical characteristic curves measured at 25°C ambient temperature. While the specific graphs are not detailed in the provided text, such curves typically include:

• Forward Current vs. Forward Voltage (I-V Curve): Shows the nonlinear relationship, critical for designing current-limiting circuits.
• Luminous Intensity vs. Forward Current: Demonstrates how light output increases with current, up to the maximum rating.
• Luminous Intensity vs. Ambient Temperature: Shows the decrease in output as temperature rises, important for thermal management.
• Spectral Distribution: A plot of relative intensity versus wavelength, centered around the peak wavelength of 468 nm with a ~25 nm half-width.

These curves are essential for predicting performance under non-standard conditions.

5. Mechanical and Packaging Information

5.1 Package Dimensions

The LED conforms to an EIA standard SMD package. All dimensions are provided in millimeters with a general tolerance of ±0.10 mm. The specific footprint and height are defined in the package drawing, which is crucial for PCB (Printed Circuit Board) layout.

5.2 Polarity Identification and Pad Design

As a reverse mount component, the orientation for soldering is opposite to standard top-emitting LEDs. The datasheet includes suggested soldering pad dimensions to ensure a reliable solder joint and proper alignment during reflow. Correct polarity identification is vital to prevent incorrect installation.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Profile

A suggested infrared reflow profile for lead-free (Pb-free) processes is provided. Key parameters include a pre-heat zone (150-200°C), a maximum peak temperature of 260°C, and a time above liquidus not exceeding 10 seconds. The profile is based on JEDEC standards to ensure reliability. The datasheet notes that the optimal profile may vary based on PCB design, solder paste, and oven characteristics, and recommends board-specific characterization.

6.2 Hand Soldering

If hand soldering is necessary, a soldering iron temperature not exceeding 300°C is recommended, with a maximum soldering time of 3 seconds per pad, for one time only.

6.3 Cleaning

Cleaning should only be done if necessary. Approved agents are ethyl alcohol or isopropyl alcohol at normal temperature for less than one minute. The use of unspecified chemicals is prohibited as they may damage the LED package.

6.4 Storage Conditions

For unopened, moisture-proof bags with desiccant, storage should be at ≤30°C and ≤90% Relative Humidity (RH), with a shelf life of one year. Once opened, LEDs should be stored at ≤30°C and ≤60% RH. Components removed from their original packaging are recommended to undergo IR reflow within 672 hours (28 days, MSL 2a). For storage beyond this period, baking at approximately 60°C for at least 20 hours before assembly is advised.

7. Packaging and Ordering Information

7.1 Tape and Reel Specifications

The LEDs are supplied on 8mm wide embossed carrier tape, sealed with cover tape, and wound onto 7-inch (178mm) diameter reels. Standard reel quantity is 3000 pieces. A minimum order quantity of 500 pieces is specified for remainders. Packaging follows ANSI/EIA 481 standards, with a maximum of two consecutive missing components allowed per reel.

8. Application Recommendations

8.1 Typical Application Scenarios

This blue LED is suitable for a wide range of applications requiring indicator lights, backlighting, or decorative lighting in consumer electronics, office equipment, communication devices, and household appliances. Its reverse mount design makes it ideal for applications where the light is intended to be emitted through a substrate or panel from the opposite side of the PCB.

8.2 Design Considerations

• Current Limiting: Always use a series resistor or constant current driver to limit the forward current to 20 mA DC or below.
• ESD Protection: Implement ESD safeguards during handling and assembly, as LEDs are sensitive to static discharge.
• Thermal Management: Ensure the PCB design allows for adequate heat dissipation, especially when operating at high ambient temperatures or near maximum current, to maintain luminous output and longevity.
• Optical Design: Consider the wide 130-degree viewing angle when designing light guides or lenses.

9. Technical Comparison and Differentiation

The primary differentiating features of this LED are its reverse mount configuration and its use of an ultra-bright InGaN chip. Compared to standard top-emitting LEDs, the reverse mount package offers design flexibility for specific optical paths. The InGaN technology provides higher efficiency and brighter blue light output compared to older technologies. The comprehensive binning system also allows for tighter control over color and brightness in production runs, which is an advantage for applications requiring color consistency.

10. Frequently Asked Questions (FAQs)

Q: What is the purpose of a reverse mount LED?
A: A reverse mount LED is designed to be soldered onto the PCB with its light-emitting surface facing downwards. The light is then emitted through a hole or aperture in the board, or through a translucent material. This is useful for creating sleek, flush-mounted indicator lights.

Q: Can I drive this LED directly from a 5V supply?
A: No. The forward voltage ranges from 2.8V to 3.8V. Connecting it directly to 5V would cause excessive current to flow, potentially destroying the LED. You must use a current-limiting resistor or regulator.

Q: What does the bin code (e.g., D9, Q, AC) on the reel label mean?
A: It specifies the electrical and optical characteristics of the LEDs on that reel. "D9" indicates a forward voltage between 3.20V and 3.40V. "Q" indicates a luminous intensity between 71.0 and 112.0 mcd. "AC" indicates a dominant wavelength between 465.0 and 470.0 nm.

Q: How long can I store these LEDs after opening the bag?
A: For best results and to avoid moisture-sensitive level (MSL) issues, they should be soldered within 672 hours (28 days) of exposure to ambient factory conditions (<30°C/60% RH). If stored longer, baking is required.

11. Practical Design and Usage Case

Scenario: Designing a status indicator panel for a network router.
A designer needs multiple bright blue LEDs to indicate "Power," "Internet," and "Wi-Fi" status. The panel design calls for the light to shine through small, laser-etched icons on a front plastic bezel, with the PCB mounted behind it. Using this reverse mount blue LED is ideal. The designer would:
1. Place the LEDs on the bottom side of the PCB, aligned with holes under each icon.
2. Select a bin code (e.g., R for high brightness, AD for a slightly greener-blue tint) to ensure uniform appearance.
3. Design the PCB footprint exactly per the suggested pad layout.
4. Calculate a current-limiting resistor for a 3.3V supply: R = (3.3V - VF_typical) / 0.020A. Using a typical VF of 3.3V, R = 0 ohms, which is not feasible. Therefore, they would use a lower current (e.g., 15 mA) or select a bin with a lower VF (D7 or D8) to have a usable resistor value, ensuring the LED operates within specifications.

12. Technical Principle Introduction

This LED is based on a semiconductor diode structure made from Indium Gallium Nitride (InGaN). When a forward voltage is applied, electrons and holes recombine in the active region of the semiconductor, releasing energy in the form of photons (light). The specific composition of the InGaN alloy determines the bandgap energy, which directly corresponds to the wavelength (color) of the emitted light—in this case, blue (~468 nm). The "reverse mount" refers purely to the mechanical packaging orientation; the underlying electroluminescence principle remains the same as any standard LED.

13. Industry Trends and Developments

The trend in SMD LEDs continues towards higher efficiency (more lumens per watt), smaller package sizes, and improved reliability. InGaN technology for blue and green LEDs has seen steady improvements in output and longevity. There is also a growing emphasis on tighter color and intensity binning to meet the demands of applications like full-color displays and architectural lighting, where consistency is critical. Furthermore, packaging advancements focus on improving thermal performance to allow higher drive currents without compromising lifespan, and on enhancing compatibility with automated pick-and-place and reflow soldering processes for cost-effective mass production.