SMD Blue LED 19-217 Datasheet - Package 2.0x1.25x0.8mm - Voltage 2.6-2.9V - Power 40mW - English Technical Documentation

1. Product Overview

The 19-217 is a compact, surface-mount blue LED designed for modern electronic applications requiring reliable indicator and backlighting solutions. This component utilizes an InGaN (Indium Gallium Nitride) semiconductor chip to produce light in the blue spectrum, with a typical peak wavelength of 468 nanometers. Its primary advantage lies in its miniature footprint, which enables significant space savings on printed circuit boards (PCBs) and facilitates higher packing density compared to traditional leaded components. The device is fully compliant with contemporary environmental and manufacturing standards, including RoHS (Restriction of Hazardous Substances), EU REACH regulations, and is classified as halogen-free.

1.1 Core Advantages and Target Market

The design of the 19-217 SMD LED offers several key benefits for engineers and designers. Its small size and lightweight nature make it ideal for applications where space and weight are critical constraints. The package is supplied on 8mm tape wound on a 7-inch diameter reel, making it fully compatible with high-speed automated pick-and-place assembly equipment, thereby streamlining the manufacturing process. The LED is also compatible with standard infrared and vapor phase reflow soldering processes. Its primary target markets include automotive electronics (for dashboard and switch backlighting), telecommunications equipment (for indicators in phones and fax machines), consumer electronics for LCD backlighting, and general-purpose indicator applications.

2. Technical Parameter Deep-Dive

This section provides a detailed, objective analysis of the key electrical, optical, and thermal parameters specified in the datasheet, crucial for proper circuit design and reliability assessment.

2.1 Absolute Maximum Ratings

The Absolute Maximum Ratings define the stress limits beyond which permanent damage to the device may occur. These are not conditions for normal operation.

• Reverse Voltage (VR): 5V. Exceeding this voltage in reverse bias can cause junction breakdown.
• Continuous Forward Current (IF): 10mA. The maximum DC current that can be applied continuously.
• Peak Forward Current (IFP): 40mA. This is the maximum allowable pulsed current, specified at a duty cycle of 1/10 and a frequency of 1kHz. It is suitable for brief, high-intensity pulses but not for sustained operation.
• Power Dissipation (Pd): 40mW. The maximum power the package can dissipate as heat, calculated as Forward Voltage (VF) * Forward Current (IF). Operating near this limit requires careful thermal management.
• Electrostatic Discharge (ESD) Human Body Model (HBM): 150V. This is a relatively low ESD tolerance, indicating the device is sensitive to static electricity. Proper ESD handling procedures are mandatory during assembly and handling.
• Operating Temperature (Topr): -40°C to +85°C. The ambient temperature range over which the device is guaranteed to meet its published specifications.
• Storage Temperature (Tstg): -40°C to +90°C.
• Soldering Temperature: The device can withstand reflow soldering with a peak temperature of 260°C for up to 10 seconds, or hand soldering at 350°C for up to 3 seconds per terminal.

2.2 Electro-Optical Characteristics

These parameters are measured at a standard test condition of Ta=25°C and IF=2mA, unless otherwise noted. They define the optical performance of the LED.

• Luminous Intensity (Iv): Ranges from a minimum of 7.2 mcd to a maximum of 18.0 mcd. The typical value is not specified, indicating performance is managed through a binning system (see Section 3).
• Viewing Angle (2θ1/2): 120 degrees. This is the full angle at which the luminous intensity drops to half of its peak value. A 120° angle provides a wide, diffuse emission pattern suitable for area illumination and backlighting.
• Peak Wavelength (λp): 468 nm (typical). This is the wavelength at which the spectral power distribution is at its maximum.
• Dominant Wavelength (λd): 465.0 nm to 470.0 nm. This is the single-wavelength perception of the LED's color by the human eye and is the parameter used for color binning.
• Spectral Bandwidth (Δλ): 25 nm (typical). This is the width of the emitted spectrum, measured at half the maximum intensity (Full Width at Half Maximum - FWHM).
• Forward Voltage (VF): 2.60V to 2.90V at IF=2mA. This range is critical for designing the current-limiting circuitry.
• Reverse Current (IR): Maximum 50 μA at VR=5V. The datasheet explicitly notes that the device is not designed for reverse operation; this parameter is for test purposes only.

3. Binning System Explanation

To ensure consistent performance in mass production, LEDs are sorted into bins based on key parameters. The 19-217 uses a three-dimensional binning system.

3.1 Luminous Intensity Binning

LEDs are categorized into four bins (K1, K2, L1, L2) based on their measured luminous intensity at 2mA.

• Bin K1: 7.2 - 9.0 mcd
• Bin K2: 9.0 - 11.5 mcd
• Bin L1: 11.5 - 14.5 mcd
• Bin L2: 14.5 - 18.0 mcd

A tolerance of ±11% is applied to the bin limits.

3.2 Dominant Wavelength Binning

The color is controlled within a single bin for this product.

• Bin X: 465.0 - 470.0 nm. A tight tolerance of ±1nm is specified.

3.3 Forward Voltage Binning

Forward voltage is sorted into three bins to aid in designing consistent current drivers.

• Bin 28: 2.60 - 2.70V
• Bin 29: 2.70 - 2.80V
• Bin 30: 2.80 - 2.90V

A tolerance of ±0.05V is applied.

4. Performance Curve Analysis

The datasheet provides several characteristic graphs that are essential for understanding the LED's behavior under different operating conditions.

4.1 Relative Luminous Intensity vs. Forward Current

This curve shows that luminous output is not linear with current. It increases with current but will eventually saturate. Operating above the recommended continuous current (10mA) may lead to reduced efficiency and accelerated aging.

4.2 Relative Luminous Intensity vs. Ambient Temperature

This graph demonstrates the negative temperature coefficient of LED light output. As the junction temperature increases, the luminous intensity decreases. For the 19-217, the output can drop significantly as the ambient temperature approaches the maximum operating limit of 85°C. This must be factored into designs requiring consistent brightness over a wide temperature range.

4.3 Forward Current Derating Curve

This is one of the most critical graphs for reliability. It shows the maximum allowable continuous forward current as a function of ambient temperature. As temperature rises, the maximum safe current decreases. At 85°C, the allowable current is substantially lower than the 10mA rating at 25°C. Failure to derate the current can lead to thermal runaway and device failure.

4.4 Forward Voltage vs. Forward Current

This IV (Current-Voltage) curve shows the exponential relationship typical of a diode. The voltage increases logarithmically with current. The curve is essential for selecting an appropriate current-limiting resistor or designing a constant-current driver.

4.5 Spectral Distribution and Radiation Pattern

The spectral graph confirms the blue emission centered around 468nm with a FWHM of approximately 25nm. The radiation pattern diagram illustrates the spatial distribution of light, confirming the Lambertian-like emission pattern with the specified 120° viewing angle.

5. Mechanical and Package Information

5.1 Package Dimensions

The 19-217 features a standard SMD package. Key dimensions (in millimeters) include a body size of approximately 2.0mm in length, 1.25mm in width, and 0.8mm in height. The datasheet provides a detailed drawing with tolerances of ±0.1mm unless otherwise specified. The anode and cathode are clearly marked, which is crucial for correct orientation during assembly.

5.2 Polarity Identification

Correct polarity is vital for LED operation. The package includes visual markers (typically a notch or a green marking) to identify the cathode. Designers must ensure the PCB footprint matches this orientation.

6. Soldering and Assembly Guidelines

Proper handling and soldering are critical to yield and long-term reliability.

6.1 Storage and Moisture Sensitivity

The LEDs are packaged in a moisture-resistant bag with desiccant. The bag should not be opened until the components are ready for use. After opening, unused parts should be stored at ≤30°C and ≤60% Relative Humidity (RH) and used within 168 hours (7 days). If this window is exceeded, a baking treatment at 60±5°C for 24 hours is required before soldering to prevent "popcorning" (package cracking due to vapor pressure during reflow).

6.2 Reflow Soldering Profile

A lead-free reflow profile is specified:

• Pre-heating: 150-200°C for 60-120 seconds.
• Time Above Liquidus (TAL): Above 217°C for 60-150 seconds.
• Peak Temperature: Maximum 260°C, held for a maximum of 10 seconds.
• Ramp Rates: Maximum 6°C/sec heating, 3°C/sec cooling.

Reflow soldering should not be performed more than two times. Stress on the LED body during heating and warping of the PCB after soldering must be avoided.

6.3 Hand Soldering and Rework

If hand soldering is necessary, the iron tip temperature must be below 350°C, applied for no more than 3 seconds per terminal, using a soldering iron with a power rating below 25W. A cooling interval of at least 2 seconds should be allowed between terminals. Rework is strongly discouraged. If unavoidable, a specialized double-head soldering iron must be used to simultaneously heat both terminals and prevent mechanical stress on the solder joints.

7. Packaging and Ordering Information

7.1 Reel and Tape Specifications

The components are supplied in embossed carrier tape with dimensions provided in the datasheet. The tape is 8mm wide and wound on a standard 7-inch (178mm) diameter reel. Each reel contains 3000 pieces.

7.2 Label Explanation

The reel label contains critical information for traceability and correct application:

• P/N: Product Number (e.g., 19-217/BHC-XK1L2B11X/3T).
• QTY: Packing Quantity (3000 pcs).
• CAT: Luminous Intensity Rank (e.g., K1, L2).
• HUE: Chromaticity/Dominant Wavelength Rank (X).
• REF: Forward Voltage Rank (e.g., 28, 29, 30).
• LOT No: Manufacturing Lot Number for traceability.

8. Application Suggestions and Design Considerations

8.1 Typical Application Scenarios

• Automotive Interior Lighting: Backlighting for instrument clusters, buttons, and switches. The wide viewing angle and blue color are suitable for creating modern aesthetic effects.
• Consumer Electronics: Status indicators and backlighting for keys on remote controls, appliances, and audio equipment.
• Telecom and Networking Equipment: Link activity, power, and status indicators on routers, switches, and modems.
• General Panel Indicators: Any application requiring a small, reliable, and bright blue indicator light.

8.2 Critical Design Considerations

1. Current Limiting is Mandatory: An external current-limiting resistor or constant-current driver MUST be used in series with the LED. The forward voltage has a negative temperature coefficient, meaning it decreases as temperature rises. Without current limiting, a small increase in voltage or temperature can cause a large, potentially destructive increase in current.
2. Thermal Management: Consider the operating environment. Use the derating curve to select an appropriate operating current, especially if the ambient temperature is high or the PCB has poor heat dissipation.
3. ESD Protection: Implement ESD protection on input lines if the LED is user-accessible, and enforce ESD-safe handling procedures during assembly.
4. Optical Design: The 120° viewing angle provides wide coverage. For focused light, an external lens or light guide may be necessary.

9. Technical Comparison and Differentiation

While many SMD blue LEDs exist, the 19-217's combination of parameters positions it for specific use cases. Compared to smaller packages (e.g., 0402), it offers higher light output and potentially better heat dissipation due to its larger size. Compared to high-power LEDs, it operates at much lower current and requires simpler drive circuitry, making it cost-effective for indicator applications. Its explicit compliance with halogen-free and REACH standards is a key differentiator for markets with strict environmental regulations, such as the European Union.

10. Frequently Asked Questions (Based on Technical Parameters)

10.1 Why is a current-limiting resistor absolutely necessary?

LEDs are current-driven devices, not voltage-driven. The V-I characteristic is exponential. At the typical forward voltage of ~2.8V, a very small change in supply voltage or a drop in the LED's Vf due to heating can cause the current to increase dramatically, exceeding the maximum rating and destroying the device. A resistor sets a fixed current based on Ohm's Law (I = (Vsupply - Vf) / R).

10.2 Can I drive this LED directly from a 3.3V or 5V logic output?

No, not directly. A microcontroller's GPIO pin typically cannot source enough current (often limited to 20-25mA) safely and consistently for an LED, and it lacks current regulation. You must use a series resistor. For a 3.3V supply and a target current of 5mA with a Vf of 2.8V, the resistor value would be R = (3.3V - 2.8V) / 0.005A = 100 Ohms. Always check the microcontroller's pin current sourcing capability.

10.3 What does the 120° viewing angle mean for my design?

It means light is emitted in a wide cone. If you need the LED to be visible from many angles (e.g., a panel indicator), this is ideal. If you need a focused beam of light (e.g., to illuminate a specific spot), this LED alone is not suitable and would require secondary optics.

10.4 How critical is the 7-day floor life after opening the moisture barrier bag?

Very critical for reflow soldering. Moisture absorbed into the plastic package can turn to steam during the high-temperature reflow cycle, causing internal delamination or cracking ("popcorning"), which leads to immediate or latent failure. If the bag has been open longer than 168 hours, the baking procedure must be followed.

11. Practical Design and Usage Case

Scenario: Designing a status indicator for a consumer router. The LED needs to show "power on" and "WAN activity" (blinking). The system uses a 3.3V rail. To ensure long life and avoid overstressing the microcontroller, an external transistor (e.g., a small NPN or an NFET) is used to switch the LED. A series resistor is placed between the 3.3V rail and the LED anode, and the transistor switches the cathode to ground. Choosing a conservative current of 5mA for continuous "power" indication and using the max Vf of 2.9V for calculation ensures brightness under all conditions: R = (3.3V - 2.9V) / 0.005A = 80 Ohms (use a standard 82 Ohm resistor). The power dissipation in the LED is Pd = Vf * If = 2.9V * 0.005A = 14.5mW, well below the 40mW maximum, ensuring excellent reliability even in a potentially warm enclosure.

12. Operating Principle Introduction

The 19-217 LED operates on the principle of electroluminescence in a semiconductor p-n junction. The active region is composed of InGaN. When a forward voltage exceeding the junction's built-in potential is applied, electrons from the n-type region and holes from the p-type region are injected into the active region. When these charge carriers recombine, they release 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 epoxy resin package serves to protect the semiconductor die, provide mechanical stability, and acts as a primary lens to shape the light output.

13. Technology Trends and Context

This device represents a mature, cost-optimized segment of LED technology. The use of InGaN for blue emission is well-established. Current trends in indicator-type SMD LEDs focus on several areas: 1) Miniaturization: Even smaller packages than the 19-217 are available (e.g., 0402, 0201) for ultra-high-density boards. 2) Higher Efficiency: Newer chip designs and materials continue to improve lumens per watt, allowing for lower operating currents and reduced power consumption. 3) Improved Reliability and Consistency: Advanced manufacturing and binning techniques yield tighter parameter distributions. 4) Broad Environmental Compliance: As seen with this part, compliance with RoHS, REACH, and halogen-free standards is now a baseline expectation for global market access. The 19-217 fits into applications where a proven, reliable, and standardized component is preferred over cutting-edge performance.