SMD Mid-Power LED 67-22ST Datasheet - PLCC-2 Package - Voltage 34-38V - Current 25mA - White LED - English Technical Document

1. Product Overview

The 67-22ST is a surface-mount device (SMD) mid-power LED housed in a PLCC-2 (Plastic Leaded Chip Carrier) package. It is designed as a white LED solution offering a balance of performance, efficiency, and compact form factor, making it suitable for a broad range of lighting applications that require reliable and consistent light output.

1.1 Core Advantages and Positioning

This LED package is characterized by several key advantages that position it as a versatile component in the lighting market. It delivers high luminous intensity output, ensuring bright and effective illumination. The device features a wide viewing angle, typically 120 degrees, which promotes even light distribution and is ideal for applications requiring broad-area coverage. Furthermore, it is constructed using lead-free (Pb-free) materials and complies with major environmental and safety regulations including RoHS, EU REACH, and halogen-free standards (with Bromine <900ppm, Chlorine <900ppm, Br+Cl <1500ppm). The use of ANSI-standard binning for color characteristics ensures consistency and predictability in color performance across production batches.

1.2 Target Applications

The combination of high efficacy, good color rendering index (CRI), low power consumption, and a compact footprint makes this LED suitable for numerous applications. Primary use cases include general purpose lighting, decorative and entertainment lighting, status indicators, various illumination tasks, and switch backlighting.

2. Technical Parameter Analysis

This section provides a detailed, objective interpretation of the LED's key technical specifications as defined in the datasheet under standard test conditions (soldering point temperature at 25°C).

2.1 Absolute Maximum Ratings

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

• Forward Current (I_F): 36 mA (Continuous)
• Peak Forward Current (I_FP): 72 mA (Pulsed, Duty Cycle 1/10, Pulse Width 10ms)
• Power Dissipation (P_d): 1368 mW
• Operating Temperature (T_opr): -40°C to +85°C
• Storage Temperature (T_stg): -40°C to +100°C
• Thermal Resistance, Junction to Soldering Point (R_{th J-S}): 16 °C/W
• Maximum Junction Temperature (T_j): 115 °C

Important Note: The device is sensitive to electrostatic discharge (ESD). Proper ESD handling procedures must be followed during assembly and handling to prevent latent or catastrophic failure.

2.2 Electro-Optical Characteristics

These parameters are measured at the typical operating forward current of 25 mA.

• Luminous Flux (Φ): The minimum luminous flux is specified as 120 lm, with a typical tolerance of ±11%. The actual flux value depends on the specific bin code (e.g., S3A, S3B, etc.).
• Forward Voltage (V_F): Ranges from a minimum of 34 V to a maximum of 38 V at 25mA. The typical tolerance is ±0.1V, and specific voltage bins (C4 to C7) are defined for tighter control.
• Color Rendering Index (CRI/Ra): A minimum CRI of 80 is guaranteed, with a tolerance of ±2. The R9 value (saturated red) is specified as 0 minimum.
• Viewing Angle (2θ_1/2): The half-intensity angle is typically 120 degrees.

2.3 Thermal and Soldering Characteristics

Proper thermal management is critical for LED longevity and performance maintenance.

• The thermal resistance of 16 °C/W indicates the temperature rise from the junction to the solder point per watt of power dissipated. Effective PCB layout and possible use of thermal vias are recommended to manage heat.
• Reflow Soldering: The LED can withstand a peak temperature of 260°C for a maximum of 10 seconds.
• Hand Soldering: If necessary, a soldering iron tip at 350°C may be applied for a maximum of 3 seconds.

3. Binning System Explanation

The product uses a comprehensive binning system to categorize key performance variations, allowing designers to select LEDs with consistent characteristics for their application.

3.1 Luminous Flux Binning

Luminous flux is grouped into bins denoted by codes like S3A, S3B, S4A, etc. Each bin defines a minimum and maximum flux range measured at I_F=25mA. For example, bin S3A covers 120 to 125 lm, and S3B covers 125 to 130 lm. This allows for selection based on brightness requirements.

3.2 Forward Voltage Binning

Forward voltage is binned to aid in circuit design, particularly for driving multiple LEDs in series. Bins range from C4 (34.0-35.0V) to C7 (37.0-38.0V). Selecting LEDs from the same or adjacent voltage bins can help ensure more uniform current distribution in parallel strings or predictable voltage requirements in series strings.

3.3 Chromaticity and Color Temperature Binning

The datasheet provides detailed chromaticity coordinate (CIE x, y) boxes for different Correlated Color Temperatures (CCTs) like 2700K and 3000K. Multiple binning schemes are presented:

• 3-STEP and 5-STEP MacAdam Ellipses: These define tighter color consistency. A "3-STEP" bin ensures all LEDs fall within a 3-step MacAdam ellipse, representing very small color variation perceptible only under careful comparison. "5-STEP" is slightly looser but still ensures good color uniformity for most applications.
• Detailed 7-Code Chromaticity Bins: For each CCT (e.g., 2700K), further subdivision into codes like 27-7A, 27-7B, etc., is provided with specific coordinate corners and reference CCT ranges (e.g., 2580K~2718K). This allows for extremely precise color matching in critical applications.

3.4 Color Rendering Index (CRI) Index

The CRI is indicated by a letter in the part number (e.g., 'K' for CRI 80 Min.). The table defines symbols from M (CRI 60 Min.) to H (CRI 90 Min.), with the example parts all using 'K' for a minimum CRI of 80.

4. Product Numbering and Ordering Guide

4.1 Part Number Explanation

The part number follows a structured format: 67-22ST/KKE-NXX XX XX 380U2/SZM/2T

• 67-22ST/: Base package type.
• K: CRI bin code (K = 80 Min.).
• KE: Likely internal code.
• N: CRI index (N=65 Min., but overridden by 'K' in this case? The example uses KKE-N...). The example clarifies that 'K' defines CRI=80.
• First XX: Color Temperature in hundreds of Kelvin (e.g., 27 for 2700K).
• Second XX: Luminous Flux code (e.g., 12 for 120 lm min).
• Third XX: Likely a flux or color sub-bin.
• 380: Forward Voltage index (38.0V max).
• U2: Forward Current index (I_F=25mA).
• /SZM/2T: Packaging and tape specification.

Example: 67-22ST/KKE-N27120380U2/SZM/2T decodes to: CRI 80 Min., CCT 2700K, Flux 120 lm min, V_F 38.0V max, I_F 25mA.

4.2 Mass Production List

The datasheet lists specific part numbers available for mass production, covering popular CCTs at a minimum CRI of 80:

• 2700K (120 lm min)
• 3000K (125 lm min)
• 4000K (130 lm min)
• 5000K (130 lm min)
• 6500K (130 lm min)

5. Application Guidelines and Design Considerations

5.1 Typical Application Scenarios

Based on its specifications, this LED is well-suited for:

• General Indoor Lighting: Its 2700K-6500K CCT range and good CRI make it fit for ambient lighting in homes, offices, and retail spaces, especially when used in arrays on LED modules or strips.
• Decorative & Architectural Lighting: The wide viewing angle and consistent color bins are ideal for coves, shelves, signage, and facade lighting where even light spread is desired.
• Functional Illumination: Can be used in task lights, cabinet lighting, or under-cabinet lighting where its brightness and color quality are beneficial.

5.2 Driver Circuit Design

Given the high forward voltage (34-38V at 25mA), a constant-current LED driver is essential. The driver must be rated to deliver the required current while accommodating the total forward voltage of the LED string(s). For a single LED, the driver output voltage must exceed ~38V. For multiple LEDs in series, the total V_F adds up (e.g., 3 LEDs could require ~102-114V), which influences driver selection. The low current (25mA) allows for efficient driver designs and the potential to drive many parallel strings from a single current-regulated source with appropriate ballasting.

5.3 Thermal Management Design

With a power dissipation of up to ~0.95W (38V * 0.025A) and a thermal resistance of 16°C/W, the junction temperature rise from the solder point can be significant. For example, if the solder point reaches 60°C, the junction could be at 60°C + (0.95W * 16°C/W) = ~75°C, which is within limits but reduces light output and lifetime. Therefore, designing the PCB with adequate copper area (acting as a heat sink) and ensuring good airflow in the final fixture are crucial for maintaining performance and longevity.

5.4 Optical Design Considerations

The 120-degree viewing angle is inherently wide. For applications requiring a more focused beam, secondary optics such as lenses or reflectors would be necessary. The water-clear resin of the package is suitable for use with such optics without significant absorption losses.

6. Performance Curves and Chromaticity Analysis

The datasheet includes CIE 1931 chromaticity diagrams with plotted bin ranges for 2700K and 3000K. These diagrams are crucial for understanding color point variation.

6.1 Interpreting the Chromaticity Diagrams

The black-body locus (the curved line) represents the color of a theoretical perfect radiator at different temperatures. The bins (rectangles or parallelograms) show the allowable spread of color coordinates (x,y) for a given CCT bin. Choosing a tighter bin (e.g., 3-STEP) ensures all LEDs will appear nearly identical in color to the human eye, which is vital for high-quality lighting products where color mismatch is unacceptable. The provided coordinate corners allow for precise color mixing calculations in multi-LED systems.

7. Comparison and Selection Rationale

Compared to traditional through-hole LEDs, this SMD package offers significant advantages in automated assembly, thermal path to the PCB, and design miniaturization. Within the SMD mid-power segment, its key differentiators are its relatively high forward voltage (suggesting it may contain multiple die in series within the package) and the availability of tight chromaticity binning options. This makes it competitive in applications requiring good color consistency at a moderate power level, bridging the gap between low-power indicator LEDs and high-power illumination LEDs.

8. Frequently Asked Questions (FAQ)

Q: What is the typical operating current for this LED?
A: The datasheet specifies electro-optical characteristics at I_F=25mA, which is the recommended typical operating current. It can be driven up to the Absolute Maximum Rating of 36mA continuous, but this will increase heat and may reduce lifetime and efficiency.

Q: How do I interpret the luminous flux tolerance of ±11%?
A: This means the actual luminous flux of a given LED can vary by ±11% from the nominal bin value. For example, an LED from the 120 lm min bin could actually measure between approximately 107 lm and 133 lm. For consistent brightness, it's advisable to source from a single production lot.

Q: Can I drive this LED directly with a constant voltage source?
A: No. LEDs are current-driven devices. Their forward voltage has a tolerance and varies with temperature. A constant-voltage supply would lead to uncontrolled current, potentially exceeding the maximum rating and destroying the LED. Always use a constant-current driver or a current-limiting circuit.

Q: What does "halogen-free" compliance mean for my application?
A: Halogen-free materials reduce the emission of toxic and corrosive fumes (like dioxins) in case of a fire. This is increasingly important for consumer electronics, indoor lighting, and products with specific environmental or safety certifications (e.g., for use in enclosed public spaces).

9. Technical Principles and Trends

9.1 Operating Principle

This LED is based on semiconductor technology. When a forward voltage exceeding its bandgap energy is applied, electrons and holes recombine within the active region of the InGaN (Indium Gallium Nitride) chip, releasing energy in the form of photons (light). The specific composition of the semiconductor layers and the use of phosphors (for white LEDs) determine the wavelength and color of the emitted light. The PLCC-2 package provides mechanical protection, electrical connections, and a primary optical lens while facilitating heat transfer to the printed circuit board.

9.2 Industry Trends

The mid-power LED segment continues to evolve towards higher efficacy (more lumens per watt), improved color rendering (higher R9 values, fuller spectrum), and greater reliability. There is also a strong trend towards standardization of footprints and photometric data to simplify design and sourcing. The inclusion of detailed chromaticity and flux binning, as seen in this datasheet, reflects the market's demand for predictable performance and color consistency in volume production, which is critical for the replacement of traditional light sources with LED technology in professional lighting applications.