SMD LED 19-21/S2C-AL2M2VY/3T Datasheet - Size 2.0x1.25x0.8mm - Voltage 1.7-2.2V - Color Brilliant Orange - English Technical Document

1. Product Overview

The 19-21/S2C-AL2M2VY/3T is a surface-mount device (SMD) LED utilizing AlGaInP chip technology to emit a brilliant orange color. This component is designed for modern, compact electronic assemblies, offering significant advantages in board space utilization and automated manufacturing processes.

1.1 Core Advantages and Product Positioning

The primary advantage of this LED is its miniature footprint. Being significantly smaller than traditional lead-frame type LEDs, it enables the design of smaller printed circuit boards (PCBs), higher component packing density, reduced storage space requirements, and ultimately, the creation of more compact end-user equipment. Its lightweight construction further makes it an ideal choice for applications where size and weight are critical constraints.

This LED is a mono-color type, is lead-free (Pb-free), and is compliant with major environmental and safety regulations including RoHS, EU REACH, and halogen-free standards (Br <900 ppm, Cl <900 ppm, Br+Cl < 1500 ppm). It is supplied in 8mm tape on 7-inch diameter reels, making it fully compatible with standard automatic pick-and-place equipment used in high-volume electronics manufacturing. The component is also compatible with both infrared and vapor phase reflow soldering processes.

2. Technical Specifications and In-Depth Interpretation

2.1 Absolute Maximum Ratings

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

• Reverse Voltage (V_R): 5V. Exceeding this voltage in reverse bias can cause junction breakdown.
• Forward Current (I_F): 25mA (continuous).
• Peak Forward Current (I_FP): 60mA (at a duty cycle of 1/10 and 1kHz frequency). This rating is for pulsed operation only.
• Power Dissipation (P_d): 60mW. This is the maximum power the package can dissipate without exceeding its thermal limits.
• Electrostatic Discharge (ESD) Human Body Model (HBM): 2000V. This indicates a moderate level of ESD sensitivity; proper ESD handling procedures are required.
• Operating Temperature (T_opr): -40°C to +85°C. The device is rated for industrial temperature range applications.
• Storage Temperature (T_stg): -40°C to +90°C.
• Soldering Temperature: For reflow soldering, a peak temperature of 260°C for a maximum of 10 seconds is specified. For hand soldering, the iron tip temperature should not exceed 350°C for a maximum of 3 seconds per terminal.

2.2 Electro-Optical Characteristics

These parameters are measured at a standard test condition of an ambient temperature (T_a) of 25°C and a forward current (I_F) of 5mA, unless otherwise noted.

• Luminous Intensity (I_v): Ranges from a minimum of 14.5 mcd to a maximum of 28.5 mcd. The typical value falls within this range. A tolerance of ±11% applies.
• Viewing Angle (2θ_1/2): The half-intensity angle is typically 100 degrees, indicating a wide viewing pattern.
• Peak Wavelength (λ_p): Typically 611 nm.
• Dominant Wavelength (λ_d): Ranges from 600.5 nm to 612.5 nm, with a tolerance of ±1 nm. This parameter defines the perceived color.
• Spectral Bandwidth (Δλ): Typically 17 nm, measured at half the peak intensity (Full Width at Half Maximum).
• Forward Voltage (V_F): Ranges from 1.70V to 2.20V at I_F=5mA, with a tolerance of ±0.05V.
• Reverse Current (I_R): Maximum of 10 μA when a reverse voltage (V_R) of 5V is applied. Important Note: The device is not designed for operation in reverse bias; this test condition is for leakage current characterization only.

3. Binning System Explanation

To ensure color and brightness consistency in production, LEDs are sorted into bins based on key parameters.

3.1 Luminous Intensity Binning

Binned at I_F = 5mA.

• L2: 14.5 mcd to 18.0 mcd
• M1: 18.0 mcd to 22.5 mcd
• M2: 22.5 mcd to 28.5 mcd

3.2 Dominant Wavelength Binning

Binned at I_F = 5mA.

• D8: 600.5 nm to 603.5 nm
• D9: 603.5 nm to 606.5 nm
• D10: 606.5 nm to 609.5 nm
• D11: 609.5 nm to 612.5 nm

3.3 Forward Voltage Binning

Binned at I_F = 5mA.

• 19: 1.70V to 1.80V
• 20: 1.80V to 1.90V
• 21: 1.90V to 2.00V
• 22: 2.00V to 2.10V
• 23: 2.10V to 2.20V

The product code "19-21" in the part number likely references specific bins from these categories (e.g., V_F bin 19-21).

4. Performance Curve Analysis

The datasheet provides several typical characteristic curves which are crucial for design.

4.1 Spectral Distribution

The curve shows a single, dominant peak centered around 611 nm, which is characteristic of AlGaInP-based orange LEDs. The narrow bandwidth (typically 17 nm) results in a saturated, pure orange color.

4.2 Relative Luminous Intensity vs. Forward Current

This curve is generally linear at lower currents but will show saturation effects as current increases. It is essential for determining the drive current needed to achieve a desired brightness level.

4.3 Relative Luminous Intensity vs. Ambient Temperature

The luminous intensity decreases as the ambient temperature increases. This curve is critical for applications operating over a wide temperature range, as it allows designers to derate the expected output or compensate in the drive circuitry.

4.4 Forward Current Derating Curve

This graph shows the maximum allowable continuous forward current as a function of ambient temperature. As temperature rises, the maximum current must be reduced to stay within the device's power dissipation limits and prevent thermal runaway.

4.5 Forward Voltage vs. Forward Current (I-V Curve)

This standard diode curve shows the exponential relationship. The forward voltage has a negative temperature coefficient, meaning it decreases slightly as the junction temperature increases.

4.6 Radiation Pattern

The polar diagram confirms the wide, lambertian-like emission pattern with a typical 100-degree viewing angle, providing even illumination over a broad area.

5. Mechanical and Package Information

5.1 Package Dimensions

The 19-21 SMD LED has a compact rectangular package. Key dimensions (in mm, tolerance ±0.1mm unless specified) include a body size of approximately 2.0mm in length and 1.25mm in width, with a height of about 0.8mm. The detailed drawing specifies pad locations, standoff height, and the position of the cathode identification mark.

5.2 Polarity Identification

A clear cathode mark is indicated on the package and the dimension drawing. Correct polarity must be observed during assembly to prevent reverse bias damage.

6. Soldering and Assembly Guidelines

6.1 Current Limiting

Mandatory: An external current-limiting resistor or constant-current driver must always be used in series with the LED. The LED's forward voltage has a sharp knee; a small increase in supply voltage can cause a large, potentially destructive increase in current.

6.2 Storage and Moisture Sensitivity

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

1. Do not open the bag until ready for use.
2. After opening, unused LEDs should be stored at ≤30°C and ≤60% Relative Humidity.
3. The "floor life" after bag opening is 168 hours (7 days).
4. If the exposure time is exceeded or the desiccant indicator has changed color, the components must be baked at 60°C ±5°C for 24 hours before reflow soldering to prevent "popcorning" damage.

6.3 Reflow Soldering Profile

A lead-free (Pb-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 of 260°C, held for a maximum of 10 seconds.
• Ramp-up Rate: Maximum 6°C/second.
• Ramp-down Rate: Maximum 3°C/second.

Reflow soldering should not be performed more than two times. Avoid mechanical stress on the LED during heating and do not warp the PCB after soldering.

6.4 Hand Soldering and Rework

If hand soldering is necessary, use a soldering iron with a tip temperature <350°C, apply heat for ≤3 seconds per terminal, and use an iron with a power rating <25W. Allow a cooling interval of >2 seconds between terminals. Rework is strongly discouraged. If absolutely necessary, use a dual-tip soldering iron to simultaneously heat both terminals and lift the component to avoid pad damage. Always verify LED functionality after any rework.

7. Packaging and Ordering Information

7.1 Reel and Tape Specifications

The LEDs are supplied in embossed carrier tape on 7-inch diameter reels. The tape width is 8mm. Each reel contains 3000 pieces. Detailed dimensions for the carrier tape pockets and the reel are provided in the datasheet.

7.2 Label Explanation

The reel label contains several key fields:

• CPN: Customer's Product Number
• P/N: Manufacturer's Product Number (e.g., 19-21/S2C-AL2M2VY/3T)
• QTY: Packing Quantity
• CAT: Luminous Intensity Rank (Bin Code, e.g., M1)
• HUE: Chromaticity Coordinates & Dominant Wavelength Rank (Bin Code, e.g., D10)
• REF: Forward Voltage Rank (Bin Code, e.g., 20)
• LOT No: Manufacturing Lot Number for traceability.

8. Application Suggestions

8.1 Typical Application Scenarios

• Automotive Interior: Backlighting for dashboard indicators, switches, and control panels.
• Telecommunications Equipment: Status indicators and keypad backlighting in phones, fax machines, and networking hardware.
• Consumer Electronics: Flat backlighting for small LCD displays, switch illumination, and symbolic indicators.
• General Purpose Indication: Power status, mode indication, and alert signals in a wide variety of electronic devices.

8.2 Design Considerations

1. Drive Circuit: Always implement a constant-current source or a voltage source with a series resistor. Calculate the resistor value using R = (V_supply - V_F) / I_F, where V_F should be chosen from the maximum bin value (2.2V) for a robust design.
2. Thermal Management: While the power is low, ensure adequate PCB copper area or thermal vias under the LED pads if operating at high ambient temperatures or near maximum current, to help dissipate heat and maintain light output stability.
3. Optical Design: The wide 100-degree viewing angle makes it suitable for applications requiring broad-area illumination without secondary optics. For focused beams, a lens may be required.
4. ESD Protection: Incorporate ESD protection diodes on sensitive signal lines if the LED is in a user-accessible location, as the device has a 2kV HBM rating.

9. Technical Comparison and Differentiation

Compared to older through-hole LED technologies, the 19-21 SMD LED offers:

• Size Reduction: Drastically smaller footprint and profile.
• Manufacturing Efficiency: Enables fully automated, high-speed assembly.
• Performance: AlGaInP technology provides high efficiency and good color saturation in the orange/red spectrum.
• Reliability: Solid SMD construction is generally more robust against vibration and mechanical shock than devices with wire bonds to a lead frame.

Compared to some other SMD orange LEDs, the specific binning structure (Luminous Intensity, Dominant Wavelength, Forward Voltage) of this part allows for tighter system-level color and brightness matching when multiple LEDs are used in an array.

10. Frequently Asked Questions (FAQs)

Q: What is the difference between peak wavelength and dominant wavelength?
A: Peak wavelength (λ_p) is the wavelength at which the spectral power distribution is maximum. Dominant wavelength (λ_d) is the single wavelength of monochromatic light that matches the perceived color of the LED. For LEDs with a symmetric spectrum, they are often close, but λ_d is more relevant for color specification.

Q: Can I drive this LED at 20mA continuously?
A: Yes, the absolute maximum continuous forward current is 25mA, so 20mA is within specification. However, you must refer to the derating curve if the ambient temperature is significantly above 25°C, and ensure proper heat dissipation.

Q: Why is the reverse voltage rating only 5V?
A: This LED is not designed to be operated in reverse bias. The 5V rating is a test condition for measuring leakage current (I_R). In circuit design, you must ensure the LED is never subjected to a reverse voltage, typically by ensuring it is correctly oriented or by placing a protection diode in parallel (anti-parallel) if the application necessitates it.

Q: How do I interpret the part number 19-21/S2C-AL2M2VY/3T?
A: While the full decoding may be proprietary, a common pattern is: "19-21" likely indicates forward voltage bin range, "S2C" may refer to the package size/style (2.0x1.25mm), "AL2M2VY" likely encodes the chip material (AlGaInP), color (Brilliant Orange), and other attributes, and "3T" may indicate tape-and-reel packaging.

11. Practical Design Case Study

Scenario: Designing a cluster of three orange status indicators for a consumer device powered by a 5V rail. The goal is uniform brightness and color.

Design Steps:

1. Current Selection: Choose I_F = 10mA for a good balance of brightness and longevity, well below the 25mA maximum.
2. Voltage Calculation: Use the maximum V_F from the datasheet (2.20V) for a conservative design. Series resistor R = (5V - 2.20V) / 0.010A = 280Ω. The nearest standard E24 value is 270Ω or 300Ω. Choosing 270Ω gives I_F ≈ (5-2.2)/270 = 10.37mA.
3. Power in Resistor: P = I²R = (0.01037)² * 270 ≈ 0.029W. A standard 1/10W (0.1W) resistor is more than sufficient.
4. Ensuring Uniformity: To achieve uniform appearance, specify tight binning requirements when ordering: request all LEDs from the same Dominant Wavelength bin (e.g., D10) and the same Luminous Intensity bin (e.g., M1). Using individual resistors for each LED (rather than one resistor for all in parallel) compensates for small V_F variations and ensures equal current.
5. Layout: Place the LEDs with adequate spacing to prevent thermal coupling. Follow the recommended pad layout from the dimension drawing for reliable soldering.

12. Technology Principle Introduction

The 19-21 LED is based on AlGaInP (Aluminum Gallium Indium Phosphide) semiconductor material. This compound semiconductor allows for the direct bandgap engineering necessary to produce efficient light emission in the orange, red, and yellow spectral regions. When a forward voltage is applied across the p-n junction, electrons and holes are injected into the active region where they recombine, releasing energy in the form of photons. The specific ratio of aluminum, gallium, and indium in the crystal lattice determines the bandgap energy and thus the wavelength (color) of the emitted light. The water-clear resin encapsulant protects the chip and acts as a primary lens, shaping the emitted light into the wide viewing angle pattern.

13. Industry Trends and Developments

The market for SMD LEDs like the 19-21 continues to evolve. Key trends include:

• Increased Efficiency: Ongoing material science and chip design improvements lead to higher luminous efficacy (more light output per electrical watt), allowing for lower drive currents and reduced system power consumption.
• Miniaturization: The drive for smaller devices pushes package sizes even smaller than the 19-21 (e.g., 1608, 1005 metric sizes), while maintaining or improving performance.
• Enhanced Reliability and Lifetime: Improvements in packaging materials, die attach, and wire bonding (or flip-chip designs) are extending operational lifetimes and improving performance under high-temperature and high-humidity conditions.
• Smart Integration: A broader trend involves integrating control circuitry, such as constant-current drivers or even addressable controllers (like WS2812), directly into the LED package, simplifying system design for complex lighting effects.
• Sustainability: The focus on halogen-free, lead-free, and REACH-compliant materials, as seen in this datasheet, is a standard industry requirement driven by global environmental regulations.

While the fundamental AlGaInP technology for orange/red is mature, these packaging and integration trends ensure that components like the 19-21 remain relevant and improve over time.