SMD LED 19-118/BHC-ZL1M2QY/3T Datasheet - Blue 468nm - 2.7-3.2V - 25mA - 95mW - English Technical Document

1. Product Overview

This document provides the complete technical specifications for a surface-mount device (SMD) LED identified as 19-118/BHC-ZL1M2QY/3T. This is a mono-color, blue LED designed for high-density electronic assemblies.

1.1 Core Advantages and Product Positioning

The primary advantage of this component is its compact SMD package, which enables significant reductions in board size and equipment footprint compared to traditional lead-frame type LEDs. This miniaturization supports higher packing density on PCBs and reduces storage space requirements. The lightweight nature of the package makes it particularly suitable for miniature and space-constrained applications. The product is compliant with Pb-free manufacturing processes and is designed to remain within RoHS compliance standards.

1.2 Target Applications

This LED is versatile and finds use in several key application areas:

• Backlighting: Ideal for dashboard indicators and switch illumination.
• Telecommunications: Serves as status indicators and backlighting for devices such as telephones and fax machines.
• Display Technology: Used for flat backlighting of LCDs, switches, and symbols.
• General Purpose: Suitable for a wide range of indicator and illumination tasks in consumer and industrial electronics.

2. Technical Parameter Deep-Dive

This section provides a detailed, objective analysis of the LED's key performance parameters under standard test conditions (Ta=25°C).

2.1 Device Selection and Material Composition

The LED chip is constructed using Indium Gallium Nitride (InGaN) semiconductor material, which is responsible for emitting blue light. The encapsulating resin is water-clear, optimizing light output and color purity.

2.2 Absolute Maximum Ratings

These ratings define the limits beyond which permanent damage to the device may occur. Operation under or at these conditions is not guaranteed.

• Reverse Voltage (V_R): 5 V - Exceeding this voltage in reverse bias can damage the LED junction.
• Continuous Forward Current (I_F): 25 mA - The maximum DC current for reliable operation.
• Peak Forward Current (I_FP): 100 mA (Duty 1/10 @1KHz) - Suitable for pulsed operation but not for continuous use.
• Power Dissipation (P_d): 95 mW - The maximum power the package can dissipate as heat.
• Electrostatic Discharge (ESD) Human Body Model (HBM): 2000 V - Indicates a moderate level of ESD sensitivity; proper handling procedures are necessary.
• Operating Temperature (T_opr): -40°C to +85°C - The ambient temperature range for normal operation.
• Storage Temperature (T_stg): -40°C to +90°C.
• Soldering Temperature: The device can withstand reflow soldering at 260°C for 10 seconds or hand soldering at 350°C for 3 seconds.

2.3 Electro-Optical Characteristics

These parameters define the light output and electrical behavior under a standard test current of 5mA.

• Luminous Intensity (I_v): Ranges from a minimum of 11.5 mcd to a maximum of 28.5 mcd. The typical value is not specified, indicating performance is managed through a binning system.
• Viewing Angle (2θ_1/2): 120 degrees (typical). This wide viewing angle makes it suitable for applications requiring broad illumination or visibility from multiple angles.
• Peak Wavelength (λ_p): 468 nm (typical). This is the wavelength at which the spectral power distribution is maximum.
• Dominant Wavelength (λ_d): Ranges from 465 nm to 475 nm. This is the single wavelength perceived by the human eye, closely related to the color point.
• Spectral Bandwidth (Δλ): 35 nm (typical). This defines the spread of the emitted spectrum around the peak wavelength.
• Forward Voltage (V_F): Ranges from 2.7 V to 3.2 V at 5mA. Designers must account for this voltage range when selecting current-limiting resistors.

Note on Tolerances: The datasheet specifies manufacturing tolerances: Luminous Intensity (±11%), Dominant Wavelength (±1nm), and Forward Voltage (±0.05V). These are critical for understanding the variance between individual units.

3. Binning System Explanation

To ensure consistency in applications, LEDs are sorted (binned) based on key parameters. This device uses a three-dimensional binning system.

3.1 Luminous Intensity Binning

LEDs are categorized into four bins (L1, L2, M1, M2) based on their measured luminous intensity at I_F=5mA. This allows designers to select the brightness grade required for their application, ensuring uniform appearance in multi-LED designs.

3.2 Dominant Wavelength Binning

The color (hue) is controlled by sorting into two wavelength bins: X (465-470 nm) and Y (470-475 nm). This minimizes color variation within an assembly.

3.3 Forward Voltage Binning

LEDs are binned into five groups (29 to 33) based on their forward voltage drop at I_F=5mA. Knowing the V_F bin can help in designing more consistent current drive circuits, especially when LEDs are connected in parallel.

4. Performance Curve Analysis

The datasheet includes several characteristic curves that illustrate device behavior under varying conditions. These are essential for robust circuit design.

• Relative Luminous Intensity vs. Forward Current: Shows how light output increases with current. It is non-linear, and operating above the recommended current leads to diminishing returns and increased heat.
• Forward Voltage vs. Forward Current: Demonstrates the diode's IV characteristic. The voltage increases logarithmically with current.
• Forward Current Derating Curve: Indicates how the maximum allowable continuous forward current must be reduced as the ambient temperature increases above 25°C to prevent overheating.
• Luminous Intensity vs. Ambient Temperature: Shows that light output typically decreases as the junction temperature rises, a key consideration for thermal management.
• Spectrum Distribution: A graph of relative intensity versus wavelength, centered around 468 nm with a typical 35 nm bandwidth.
• Radiation Diagram: A polar plot illustrating the spatial distribution of light intensity, confirming the 120-degree viewing angle.

5. Mechanical and Package Information

5.1 Package Dimensions

The datasheet provides a detailed dimensional drawing of the LED package. Critical dimensions include the overall length, width, and height, as well as the placement and size of the solderable terminals. All unspecified tolerances are ±0.1mm.

5.2 Recommended Solder Pad Design

A suggested solder pad layout is provided for PCB design. The datasheet explicitly states this is for reference only and should be modified based on individual manufacturing processes and thermal requirements. Proper pad design is crucial for reliable soldering and mechanical strength.

6. Soldering and Assembly Guidelines

Adherence to these guidelines is critical for maintaining device reliability and performance.

6.1 Soldering Process Compatibility

The LED is compatible with both infrared and vapor phase reflow soldering processes. A detailed Pb-free reflow soldering temperature profile is provided, specifying pre-heating, time above liquidus (217°C), peak temperature (260°C max for 10 sec max), and cooling rates. Reflow soldering should not be performed more than two times.

6.2 Hand Soldering Precautions

If hand soldering is necessary, the iron tip temperature must be below 350°C, applied for no more than 3 seconds per terminal. A low-power iron (<25W) is recommended, with an interval of more than 2 seconds between soldering each terminal to prevent thermal shock.

6.3 Storage and Moisture Sensitivity

The LEDs are packaged in moisture-resistant bags with desiccant.

• Before opening: Store at ≤30°C and ≤90% RH.
• After opening: The "floor life" is 1 year at ≤30°C and ≤60% RH. Unused parts should be resealed.
• Baking: If the desiccant indicator changes or storage time is exceeded, bake at 60±5°C for 24 hours before use in a reflow process.

6.4 Critical Application Notes

• Current Limiting: An external current-limiting resistor is mandatory. The LED's exponential IV characteristic means a small voltage change causes a large current change, which can lead to immediate failure (burn-out).
• Stress Avoidance: Do not apply mechanical stress to the LED during heating (soldering) or by warping the PCB afterward.
• Repairing: Repair after soldering is discouraged. If unavoidable, a double-head soldering iron must be used to simultaneously heat both terminals and prevent damaging thermal stress. The impact on LED characteristics must be evaluated beforehand.

7. Packaging and Ordering Information

7.1 Reel and Tape Specifications

The device is supplied in 8mm tape on 7-inch diameter reels, compatible with standard automatic pick-and-place equipment. Each reel contains 3000 pieces. Detailed dimensional drawings for the carrier tape and the reel are provided.

7.2 Label Explanation

The reel label contains several codes:

• P/N: Product Number.
• CAT: Luminous Intensity Rank (bin code).
• HUE: Chromaticity Coordinates & Dominant Wavelength Rank (bin code).
• REF: Forward Voltage Rank (bin code).
• LOT No: Traceability lot number.

8. Application Design Considerations

8.1 Circuit Design

Always use a series resistor to set the forward current. Calculate the resistor value using the maximum forward voltage from the datasheet (3.2V) and the target supply voltage to ensure the current never exceeds 25mA under worst-case conditions. Consider the forward voltage binning if designing parallel arrays to ensure current sharing.

8.2 Thermal Management

While the package is small, power dissipation (up to 95mW) generates heat. Use the derating curve to limit current at high ambient temperatures. Ensure adequate PCB copper area or thermal vias are used if operating at high currents or in warm environments to maintain junction temperature within limits and preserve luminous output and lifespan.

8.3 Optical Integration

The 120-degree viewing angle provides broad emission. For applications requiring focused light, external lenses or reflectors will be necessary. The water-clear resin is suitable for use with secondary optics.

9. Technical Comparison and Positioning

Compared to through-hole LEDs, this SMD type offers the clear advantages of miniaturization, suitability for automated assembly, and better high-frequency performance due to lower parasitic inductance. Within the SMD blue LED segment, its key differentiators are its specific combination of 468nm wavelength, wide 120-degree viewing angle, and the detailed three-parameter binning system which allows for high consistency in demanding applications. The 2000V ESD rating is standard; designs in environments with higher ESD risk may require additional external protection.

10. Frequently Asked Questions (Based on Technical Parameters)

Q: Why is a current-limiting resistor absolutely necessary?
A: The LED's forward voltage has a negative temperature coefficient and manufacturing tolerance. Without a resistor, a small increase in supply voltage or a drop in V_F due to heating can cause current to rise uncontrollably, leading to rapid thermal runaway and destruction.

Q: Can I drive this LED with a 3.3V supply without a resistor?
A: No. Even if 3.3V is within the V_F range (2.7-3.2V), the lack of a current limit makes the circuit extremely sensitive to variations. The current could easily exceed the 25mA maximum, damaging the LED.

Q: What do the bin codes (L1, M2, X, Y, 30, 31) mean for my design?
A> They allow you to specify the brightness, color, and electrical consistency you need. For a multi-LED display, specifying tight bins (e.g., all M1 for intensity, all X for wavelength) ensures uniform appearance. Knowing the V_F bin helps predict power consumption.

Q: How many times can I reflow solder this component?
A> The datasheet specifies a maximum of two reflow soldering cycles. Each cycle subjects the component to thermal stress, and exceeding this limit can compromise internal bonds or the encapsulant.

11. Design and Usage Case Study

Scenario: Designing a status indicator panel with 20 uniform blue LEDs.

1. Specification: Select bins for consistency. Choose all LEDs from intensity bin M1 (18.0-22.5 mcd) and wavelength bin X (465-470 nm) to guarantee matching brightness and color.
2. Circuit Design: Using a 5V supply and a target current of 20mA (below the 25mA max for margin). Using the max V_F of 3.2V, calculate R = (5V - 3.2V) / 0.020A = 90 Ohms. Use the next standard value (91 Ohms). Re-calculate actual current with min V_F: I = (5V - 2.7V) / 91 = ~25.3mA (still at limit, acceptable with binning). A safer approach is to use 100 Ohms.
3. PCB Layout: Place the recommended solder pads. Include a small thermal relief connecting to a ground plane to help dissipate heat, as total power for 20 LEDs could be up to ~1.3W.
4. Assembly: Follow the provided reflow profile. Keep the sealed reels in a dry cabinet until ready for use in the pick-and-place machine.

12. Operational Principle

This is a semiconductor photonic device. When a forward voltage exceeding its bandgap energy is applied across the InGaN p-n junction, electrons and holes recombine. In this material system, the energy released during recombination is emitted as photons (light) with a wavelength corresponding to the bandgap energy of the InGaN alloy, which is engineered to produce blue light centered around 468 nm. The water-clear epoxy resin encapsulant protects the chip, acts as a lens to shape the light output, and enhances light extraction from the semiconductor.

13. Technology Trends

Blue InGaN LEDs represent a mature and foundational technology. Trends in the broader LED industry that influence components like this one include:

• Increased Efficiency: Ongoing development aims to improve the internal quantum efficiency (more light generated per electron) and light extraction efficiency (more light escaping the chip).
• Miniaturization: The drive for smaller devices (like this SMD LED) continues, enabling ever more compact electronic products.
• Improved Color Consistency: Advanced epitaxial growth and binning processes lead to tighter wavelength and intensity distributions, reducing the need for selective binning in some applications.
• Enhanced Reliability: Improvements in packaging materials and die attach technologies aim to increase operational lifetime and resistance to thermal and environmental stress.

This component sits within these trends, offering a reliable, standardized solution for blue indicator and backlight applications where specific wavelength and package size are key requirements.