SMD Blue LED 19-217/B7C-ZL2N1B3X/3T Datasheet - 2.0x1.25x0.8mm - 2.5-2.9V - 40mW - English Technical Document

1. Product Overview

The 19-217/B7C-ZL2N1B3X/3T is a compact, surface-mount blue LED designed for modern electronic applications requiring high reliability and efficient assembly. This component represents a significant advancement over traditional lead-frame LEDs, enabling substantial miniaturization and performance improvements in end products.

1.1 Core Advantages and Product Positioning

The primary advantage of this LED is its miniature footprint. The SMD package allows for significantly smaller printed circuit board (PCB) designs, leading to higher component packing density. This directly translates to reduced equipment size and lower storage requirements for both components and finished goods. Furthermore, the lightweight nature of the SMD package makes it ideal for portable and miniature applications where weight is a critical factor. The product is positioned as a reliable, industry-standard blue indicator and backlight source, compliant with major environmental and safety regulations.

1.2 Key Features

• Packaging: Supplied on 8mm tape mounted on a 7-inch diameter reel, fully compatible with high-speed automatic pick-and-place equipment.
• Soldering Compatibility: Designed for use with standard infrared (IR) and vapor phase reflow soldering processes.
• Environmental Compliance: The device is Pb-free (lead-free), compliant with the EU RoHS directive, and adheres to EU REACH regulations. It is also classified as Halogen-Free, with Bromine (Br) and Chlorine (Cl) content each below 900 ppm and their sum below 1500 ppm.
• Type: Mono-color (Blue) LED with a water-clear resin lens.

2. Technical Specifications Deep Dive

This section provides a detailed, objective analysis of the LED's electrical, optical, and thermal parameters, which are crucial for robust circuit design.

2.1 Absolute Maximum Ratings

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

• Reverse Voltage (V_R): 5V. Exceeding this voltage in reverse bias can cause immediate junction breakdown.
• Continuous Forward Current (I_F): 10 mA. The DC current that can be continuously applied.
• Peak Forward Current (I_FP): 40 mA. This is permissible only under pulsed conditions (duty cycle 1/10 at 1 kHz) to handle transient surges.
• Power Dissipation (P_d): 40 mW. The maximum power the package can dissipate at 25°C ambient, calculated as V_F * I_F.
• Electrostatic Discharge (ESD): 150V (Human Body Model). Proper ESD handling procedures are mandatory during assembly.
• Operating & Storage Temperature: -40°C to +85°C (operating), -40°C to +90°C (storage).
• Soldering Temperature: Reflow: 260°C peak for 10 seconds max. Hand soldering: 350°C for 3 seconds max per terminal.

2.2 Electro-Optical Characteristics

These are the typical performance parameters measured at 25°C ambient temperature and a forward current of 2mA, unless otherwise specified.

• Luminous Intensity (I_v): Ranges from 14.5 mcd (min) to 36.0 mcd (max), with a typical tolerance of ±11%. This defines the perceived brightness of the LED.
• Viewing Angle (2θ_1/2): 120 degrees (typical). This is the full angle at which the luminous intensity is half of the peak intensity, indicating a wide viewing cone.
• Peak Wavelength (λ_p): 468 nm (typical). The wavelength at which the spectral power distribution is maximum.
• Dominant Wavelength (λ_d): 465.0 nm to 475.0 nm. This defines the perceived color of the light, with a tight tolerance of ±1 nm.
• Spectral Bandwidth (Δλ): 25 nm (typical). The width of the emitted spectrum at half its maximum power.
• Forward Voltage (V_F): 2.50V to 2.90V at I_F=2mA, with a tolerance of ±0.05V. This is critical for current-limiting resistor calculation.
• Reverse Current (I_R): Maximum 50 μA at V_R=5V. The device is not designed for operation in reverse bias.

3. Binning System Explanation

The LEDs are sorted (binned) after production based on key parameters to ensure consistency. The part number 19-217/B7C-ZL2N1B3X/3T encodes this bin information.

3.1 Luminous Intensity Binning (Codes: L2, M1, M2, N1)

LEDs are grouped into four intensity bins at I_F=2mA:

• L2: 14.5 - 18.0 mcd
• M1: 18.0 - 22.5 mcd
• M2: 22.5 - 28.5 mcd
• N1: 28.5 - 36.0 mcd

The "N1" in the part number indicates this specific unit falls into the highest brightness bin.

3.2 Dominant Wavelength Binning (Codes: X, Y)

LEDs are sorted into two wavelength bins at I_F=2mA:

• X: 465.0 - 470.0 nm
• Y: 470.0 - 475.0 nm

The "X" in the part number specifies the lower wavelength range, resulting in a slightly deeper blue hue.

3.3 Forward Voltage Binning (Codes: 27, 28, 29, 30)

LEDs are grouped into four forward voltage bins at I_F=2mA:

• 27: 2.50 - 2.60 V
• 28: 2.60 - 2.70 V
• 29: 2.70 - 2.80 V
• 30: 2.80 - 2.90 V

The "3" in the part number's bin string corresponds to a V_F bin, ensuring predictable voltage drop in circuit design.

4. Performance Curve Analysis

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

4.1 Relative Luminous Intensity vs. Forward Current

This curve shows that luminous intensity increases with forward current but in a non-linear fashion. It highlights the importance of driving the LED at a stable, specified current (e.g., 2mA for rated output) rather than a voltage, as small voltage changes can cause large current and brightness variations.

4.2 Relative Luminous Intensity vs. Ambient Temperature

The output of an LED decreases as the junction temperature rises. This curve typically shows a gradual decline in intensity from low temperatures up to the maximum operating temperature (+85°C). Designers must account for this thermal derating in applications where high ambient temperatures or poor heat sinking is expected.

4.3 Forward Current Derating Curve

This is a critical design tool. It dictates the maximum allowable continuous forward current as a function of the ambient temperature. As temperature increases, the maximum safe current decreases to prevent exceeding the 40mW power dissipation limit and causing thermal runaway.

4.4 Spectrum Distribution

The spectral plot confirms a narrow emission band centered around 468 nm (blue), with a typical bandwidth of 25 nm. This pure spectrum is characteristic of InGaN semiconductor material.

4.5 Radiation Pattern

The polar diagram illustrates the 120° viewing angle, showing how light intensity is distributed spatially. The pattern is typically Lambertian or near-Lambertian, providing even illumination over a wide area.

5. Mechanical and Packaging Information

5.1 Package Dimensions

The LED has a very compact footprint. Key dimensions (in mm, tolerance ±0.1mm unless noted) include the overall length, width, and height, as well as the solder pad layout and recommended PCB land pattern. Precise dimensions are critical for PCB layout and solder paste stencil design to ensure proper soldering and alignment.

5.2 Polarity Identification

The cathode is typically marked, often by a green tint on the corresponding side of the package or a notch in the molding. Correct polarity must be observed during placement to ensure proper operation.

6. Soldering and Assembly Guidelines

Adherence to these guidelines is paramount for long-term reliability.

6.1 Reflow Soldering Profile (Pb-free)

A detailed temperature profile is provided:

• Pre-heating: 150-200°C for 60-120 seconds to slowly ramp temperature and activate flux.
• Time Above Liquidus (TAL): 60-150 seconds above 217°C.
• Peak Temperature: Maximum 260°C, held for no more than 10 seconds.
• Heating/Cooling Rates: Maximum 6°C/sec heating, 3°C/sec cooling to minimize thermal shock.

Reflow should not be performed more than two times on the same LED.

6.2 Storage and Moisture Sensitivity

The LEDs are packaged in a moisture-resistant barrier bag with desiccant.

• Do not open the bag until ready for use.
• After opening, use within 168 hours (7 days) if stored at ≤30°C and ≤60% RH.
• If the exposure time is exceeded or desiccant is saturated, a bake-out at 60±5°C for 24 hours is required before reflow to prevent "popcorning" (package cracking due to vaporized moisture).

6.3 Hand Soldering and Rework

If hand soldering is necessary:

• Use a soldering iron tip temperature ≤350°C.
• Limit contact time to ≤3 seconds per terminal.
• Use a low-power iron (≤25W).
• Allow a cooling interval of ≥2 seconds between terminals.
• Avoid rework after initial soldering. If unavoidable, use a dual-tip soldering iron to simultaneously heat both terminals and lift the component without stressing the solder joints.

7. Packaging and Ordering Information

7.1 Reel and Tape Specifications

The LEDs are supplied in embossed carrier tape on 7-inch reels. The tape width is 8mm. Each reel contains 3000 pieces. Detailed dimensions for the carrier tape pockets and the reel hub/flange are provided to ensure compatibility with automated feeders.

7.2 Label Explanation

The reel label contains several key identifiers:

• P/N: Full product number.
• QTY: Quantity on the reel.
• CAT/HUE/REF: Codes corresponding to the Luminous Intensity, Dominant Wavelength, and Forward Voltage bins, respectively.
• LOT No: Traceability lot number.

8. Application Suggestions and Design Considerations

8.1 Typical Application Scenarios

• Backlighting: Ideal for dashboard indicators, membrane switches, and symbol illumination due to its small size and even light distribution.
• Telecommunication Equipment: Status indicators and keypad backlighting in phones, fax machines, and networking hardware.
• LCD Flat Backlighting: Can be used in arrays for edge-lit or direct-lit small LCD panels.
• General Indication: Power status, mode indicators, and decorative lighting in consumer and industrial electronics.

8.2 Critical Design Considerations

1. Current Limiting: An external current-limiting resistor is absolutely mandatory. The LED's exponential I-V characteristic means a small increase in voltage causes a large increase in current, leading to rapid failure. The resistor value is calculated using R = (V_supply - V_F) / I_F.
2. Thermal Management: While power dissipation is low, ensure adequate PCB copper area or thermal vias if operating near maximum current or in high ambient temperatures, as per the derating curve.
3. ESD Protection: Implement ESD protection on input lines if the LED is user-accessible, and follow proper ESD protocols during handling.
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

Compared to older through-hole blue LEDs or larger SMD packages, the 19-217 offers distinct advantages:

• Size: Its miniature 2.0mm x 1.25mm footprint allows for unprecedented design density.
• Performance Consistency: The tight binning on intensity, wavelength, and voltage ensures uniform appearance and behavior in multi-LED applications.
• Manufacturability: Full compatibility with automated SMT assembly lines significantly reduces production cost and increases reliability compared to manual insertion.
• Compliance: Meeting RoHS, REACH, and Halogen-Free standards future-proofs the design for global markets with stringent environmental regulations.

10. Frequently Asked Questions (Based on Technical Parameters)

Q1: Why is a current-limiting resistor necessary when the forward voltage is specified?

A1: The forward voltage is a characteristic at a specific current (2mA). Power supply voltages vary, and the LED's V_F itself has a tolerance and varies with temperature. The resistor provides a linear, stable method to set the current, protecting the LED from overcurrent conditions.

Q2: Can I drive this LED at 10mA continuously?

A2: Yes, 10mA is the absolute maximum continuous rating at 25°C. However, you must consult the forward current derating curve. If the ambient temperature is higher, the maximum allowable current is lower. For reliable long-term operation, driving at a lower current like 5mA is often recommended.

Q3: What does the "B3X" in the part number mean for my design?

A3: This indicates the specific performance bin. "B3X" points to particular bins for luminous intensity and dominant wavelength. For a design requiring color and brightness consistency across multiple units or production runs, specifying and adhering to a full part number including the bin code is essential.

Q4: How do I interpret the 120° viewing angle?

A4: This means the LED emits light in a wide cone. When viewed head-on (0°), brightness is maximum. At ±60° from the center (total 120°), the brightness falls to half of the maximum value. This is suitable for applications where the LED needs to be seen from various angles.

11. Practical Design and Usage Case Study

Scenario: Designing a compact control panel with four blue status indicators.

Implementation:

1. Circuit Design: Using a 5V system supply. Target I_F = 5mA for good brightness and longevity. Assuming a typical V_F of 2.7V, calculate R = (5V - 2.7V) / 0.005A = 460Ω. Use the nearest standard value, 470Ω.
2. PCB Layout: Place the four LEDs in alignment. Follow the recommended land pattern from the datasheet precisely. Include a small copper pour connected to the cathode pads for slight thermal relief.
3. Assembly: Keep reels sealed until the production line is ready. Follow the exact reflow profile. Perform visual inspection post-soldering.
4. Result: Four indicators with consistent blue color and brightness, reliable operation, and a professional, miniaturized appearance.

12. Operating Principle Introduction

This LED is based on an Indium Gallium Nitride (InGaN) semiconductor chip. When a forward voltage exceeding the junction's built-in potential is applied, electrons and holes are injected into the active region where they recombine. This recombination process releases energy in the form of photons (light). The specific composition of the InGaN alloy determines the bandgap energy, which directly corresponds to the wavelength of the emitted light—in this case, approximately 468 nm (blue). The water-clear epoxy resin encapsulant protects the chip, acts as a lens to shape the light output, and is formulated for high optical clarity and long-term stability.

13. Technology Trends and Context

The 19-217 LED exemplifies key trends in optoelectronics: relentless miniaturization, enhanced manufacturability via SMT compatibility, and strict adherence to environmental standards. The use of InGaN technology for blue emission is now mature and highly reliable. Future evolution in such components may focus on even higher efficiency (more light output per mA), tighter parametric control for premium applications, and integration with onboard drivers or control circuitry. The demand for such compact, reliable, and compliant indicators and backlights continues to grow across automotive, industrial, consumer, and IoT device markets.