SMD Mid-Power LED 67-21ST Datasheet - PLCC-2 Package - 3.3V Max - 60mA - White - English Technical Document

1. Product Overview

The 67-21ST 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 offering a balance of performance, efficiency, and reliability for general lighting applications. Its compact form factor and standardized package make it suitable for automated assembly processes.

1.1 Core Advantages

The key advantages of this LED package include:

• High Efficacy: Delivers good luminous output relative to its power consumption.
• High Color Rendering Index (CRI): Available with minimum CRI ratings from 60 to 90, ensuring good color reproduction. The standard mass production list features CRI 80 (Min.) variants.
• Wide Viewing Angle: A typical viewing angle (2θ1/2) of 120 degrees provides broad and even illumination.
• Low Power Consumption: Operates at a standard forward current of 60mA, making it energy-efficient.
• Environmental Compliance: The product is Pb-free, compliant with EU RoHS and REACH regulations, and meets halogen-free standards (Br<900ppm, Cl<900ppm, Br+Cl<1500ppm).
• ANSI Binning: Follows standardized binning for chromaticity, ensuring color consistency across production batches.

1.2 Target Market & Applications

This LED is an ideal solution for a wide range of lighting applications that require a reliable, efficient, and compact light source. Primary application areas include:

• General Lighting: Integration into residential, commercial, and industrial luminaires.
• Decorative and Entertainment Lighting: Used in accent lighting, signage, and stage lighting.
• Indicators and Switch Lights: Suitable for backlighting buttons, panels, and status indicators.
• General Illumination: For any application requiring a diffuse, wide-angle white light source.

2. In-Depth Technical Parameter Analysis

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

2.1 Electro-Optical Characteristics

The primary performance metrics are summarized below. All values are specified at a forward current (I_F) of 60mA.

• Luminous Flux (Φ): The minimum luminous flux varies by correlated color temperature (CCT), ranging from 23 lm for 2400K to 28 lm for CCTs from 4000K to 6500K. The typical maximum can reach up to 34 lm depending on the bin. A tolerance of ±11% applies.
• Forward Voltage (V_F): The maximum forward voltage is 3.3V, with a typical range from 2.8V to 3.3V. The tolerance is ±0.1V. Lower V_F bins contribute to higher system efficiency.
• Color Rendering Index (CRI - R_a): Standard products have a minimum CRI of 80, with a tolerance of ±2. The R9 value (saturated red) is specified as 0 (min), which is typical for standard white LEDs and indicates limited deep red rendering.
• Viewing Angle (2θ_1/2): The typical value is 120 degrees, which is considered a wide viewing angle, suitable for applications requiring broad light distribution.
• Reverse Current (I_R): Maximum of 50 µA at a reverse voltage of 5V, indicating the diode's leakage characteristics.

2.2 Absolute Maximum Ratings & Electrical Parameters

These ratings define the limits beyond which permanent damage may occur. Operation should always be within these limits.

• Forward Current (I_F): 75 mA (continuous).
• Peak Forward Current (I_FP): 150 mA (pulsed, duty cycle 1/10, pulse width 10ms).
• Power Dissipation (P_d): 250 mW.
• Forward Voltage Index: Coded as "33" in the part number, corresponding to V_F max of 3.3V.
• Forward Current Index: Coded as "Z6" in the part number, corresponding to I_F of 60mA.

2.3 Thermal Characteristics

Thermal management is crucial for LED longevity and performance stability.

• Thermal Resistance (R_{th J-S}): Junction-to-soldering point thermal resistance is 21 °C/W. This value is critical for calculating the junction temperature based on the power dissipated and the board temperature.
• Junction Temperature (T_j): Maximum allowable is 125 °C. Exceeding this limit accelerates lumen depreciation and can cause catastrophic failure.
• Operating Temperature (T_opr): -40 to +105 °C. This defines the ambient temperature range for reliable operation.
• Storage Temperature (T_stg): -40 to +100 °C.

3. Binning System Explanation

The product uses a comprehensive binning system to ensure consistency in luminous flux, forward voltage, and chromaticity (color).

3.1 Luminous Flux Binning

Luminous flux is binned with specific codes. For example:

• 2400K: Bins include 23L2 (23-25 lm), 25L2 (25-27 lm), 27L2 (27-29 lm).
• 2700K to 6500K: Bins include 24L2 (24-26 lm), 26L2 (26-28 lm), 28L2 (28-30 lm), 30L2 (30-32 lm), 32L2 (32-34 lm).

All bins are measured at I_F=60mA with a ±11% tolerance.

3.2 Forward Voltage Binning

Forward voltage is grouped under code "2833" and further binned in 0.1V steps:

• 28A: 2.8 - 2.9V
• 29A: 2.9 - 3.0V
• 30A: 3.0 - 3.1V
• 31A: 3.1 - 3.2V
• 32A: 3.2 - 3.3V

The tolerance is ±0.1V. Selecting a lower V_F bin can reduce driver losses.

3.3 Chromaticity & CCT Binning

The LED uses ANSI-standard chromaticity bins defined on the CIE 1931 diagram. The datasheet provides detailed coordinate boxes for each CCT and sub-bin (e.g., 30K-A, 30K-B, 30K-C, 30K-D, 30K-F, 30K-G for 3000K). This ensures the emitted white light falls within a defined color space. The CCT range for mass production spans from 2400K (warm white) to 6500K (cool white).

3.4 Color Rendering Index (CRI) Binning

CRI is indicated by a single-letter code in the part number:

• M: CRI(Min.) 60
• N: CRI(Min.) 65
• L: CRI(Min.) 70
• Q: CRI(Min.) 75
• K: CRI(Min.) 80
• P: CRI(Min.) 85
• H: CRI(Min.) 90

The standard mass production list features the "K" bin (CRI 80 Min.). Tolerance is ±2.

4. Performance Curve Analysis & Design Considerations

While specific performance curves (IV, spectrum, temperature vs. flux) are not provided in the excerpt, key relationships can be inferred from the parameters.

4.1 Current vs. Luminous Flux/Voltage

All primary characteristics are specified at 60mA. Operating at a lower current will reduce luminous output and forward voltage, while increasing current up to the maximum 75mA will increase both. The relationship is generally linear within this range, but efficacy (lm/W) may decrease at higher currents due to increased thermal load.

4.2 Temperature Dependence

LED performance is temperature-sensitive. As junction temperature rises:

• Luminous Flux Decreases: Light output typically drops. The thermal resistance of 21°C/W is key to estimating T_j.
• Forward Voltage Decreases: V_F has a negative temperature coefficient.
• Chromaticity May Shift: The white point can shift slightly with temperature.

Proper heat sinking is essential to maintain performance and lifetime.

4.3 Spectral Distribution

As a white LED, it uses a blue InGaN chip combined with a phosphor layer (water-clear resin) to produce white light. The CCT defines the "warmth" or "coolness" of the white light. The CRI of 80 indicates good, but not exceptional, color rendering across the visible spectrum, with a noted limitation in the R9 (red) value.

5. Mechanical, Packaging & Assembly Information

5.1 Package & Dimensions

The LED uses a standard PLCC-2 surface-mount package. While exact dimensions are not detailed in the provided text, this package type typically has a low profile and is designed for pick-and-place assembly. The top view is the emitting surface.

5.2 Soldering Guidelines

The device is sensitive to electrostatic discharge (ESD) and must be handled with appropriate precautions. Soldering specifications are:

• Reflow Soldering: Maximum peak temperature of 260°C for 10 seconds.
• Hand Soldering: Iron tip temperature not to exceed 350°C for 3 seconds.

Adherence to these profiles is critical to prevent damage to the plastic package and internal die attach.

5.3 Polarity Identification

PLCC-2 packages have two leads. The cathode is typically identified by a marking on the package, such as a notch, green dot, or cut corner. Correct polarity must be observed during assembly.

6. Ordering Information & Model Number Decoding

The part number follows a specific structure: 67-21ST/KKE-HXXXX33Z6/2T

• 67-21ST/: Base package code.
• KKE: Likely internal code.
• H: Prefix for the performance code.
• XX: First two digits indicate CCT (e.g., 30 for 3000K).
• XX: Next two digits indicate minimum luminous flux bin (e.g., 26 for 26 lm min).
• 33: Forward Voltage index (3.3V max).
• Z6: Forward Current index (60mA).
• /2T: Packaging code (e.g., tape and reel).

Example: 67-21ST/KKE-H302633Z6/2T decodes to: CRI 80(Min.), CCT 3000K, Flux 26 lm min, V_F 3.3V max, I_F 60mA.

7. Application Suggestions & Design Notes

7.1 Driver Circuit Design

For stable operation, use a constant current driver set to 60mA (±10%). The driver must be capable of providing a voltage compliance above the maximum forward voltage of the selected bin (up to 3.3V + headroom). Consider inrush current protection.

7.2 Thermal Management Design

Calculate the expected junction temperature: T_j = T_s + (R_{th J-S} * P_d), where T_s is the soldering point temperature and P_d = V_F * I_F. Ensure T_j remains well below 125°C, ideally below 85°C for optimal lifetime. Use adequate copper area on the PCB for heat spreading.

7.3 Optical Design

The 120-degree viewing angle is inherently diffuse. For directional lighting, secondary optics (lenses, reflectors) will be required. The water-clear resin allows for good light extraction.

8. Technical Comparison & Market Context

The 67-21ST fits into the popular mid-power LED category, competing with other PLCC-2 and similar package types (e.g., 2835, 3014). Its differentiation lies in its specific combination of flux, CRI, and voltage bins, as well as its compliance certifications. Compared to high-power LEDs, it offers lower thermal density and is often driven in arrays for higher total lumen output. Compared to low-power LEDs, it provides significantly higher efficacy and flux.

9. Frequently Asked Questions (FAQ)

Q: What is the typical lifetime of this LED?
A: While not explicitly stated in the excerpt, LED lifetime (L70/B50) is heavily dependent on operating conditions, primarily junction temperature. When operated within specifications with good thermal management, typical lifetimes of 25,000 to 50,000 hours can be expected.

Q: Can I drive this LED at 75mA continuously?
A: Yes, 75mA is the absolute maximum continuous rating. However, driving at the maximum current will generate more heat, reduce efficacy, and potentially shorten lifespan. Operating at the recommended 60mA is advised for optimal performance and reliability.

Q: How do I select the right CCT and CRI for my application?
A: For ambient lighting (homes, offices), 2700K-4000K with CRI 80+ is common. For retail or task lighting where color accuracy is critical, consider CRI 90+ variants. For decorative lighting, the choice depends on the desired ambiance.

Q: Is a series resistor sufficient to drive this LED?
A> A simple series resistor can be used for basic, non-critical applications with a stable voltage supply. However, a constant current driver is strongly recommended for stable light output, better efficiency, and protection against voltage variations and thermal runaway.

10. Practical Use Case Example

Scenario: Designing a linear LED tube light.

1. Requirements: 1200 lm output, 4000K neutral white, CRI >80, input voltage 24V DC.
2. Selection: Choose part number 67-21ST/KKE-H402833Z6/2T (4000K, 28 lm min, V_F ~3.1V typ).
3. Array Design: To achieve 1200 lm, approximately 1200 lm / 28 lm/LED ≈ 43 LEDs are needed. Arrange them in a series-parallel configuration compatible with a 24V driver. For example, 14 series strings of 3 LEDs each (14 * 3.1V ≈ 43.4V) would require a boost driver. A more practical design might use 2 parallel strings of 22 LEDs in series (22 * 3.1V ≈ 68.2V), requiring a different driver. Detailed driver selection is needed.
4. Thermal Design: Total power ≈ 43 LEDs * 3.1V * 0.06A ≈ 8W. Ensure the metal core PCB or heatsink can dissipate this heat to keep the LED junctions cool.
5. Optical Design: Use a diffuser cover to blend the individual LED points into a uniform line of light.

This example illustrates the process of scaling from a single LED datasheet to a functional lighting product.

11. Operating Principle

The 67-21ST LED operates on the principle of electroluminescence in a semiconductor. An InGaN (Indium Gallium Nitride) chip emits blue light when a forward current is applied across its p-n junction. This blue light then excites a layer of yellow (and often red) phosphors coated on or around the chip. The combination of the blue light from the chip and the yellow/red light from the phosphors mixes to produce the perception of white light. The exact proportions of blue and phosphor-converted light determine the correlated color temperature (CCT) of the emitted white light.

12. Technology Trends & Context

Mid-power LEDs like the 67-21ST represent a mature and highly optimized segment of LED technology. Current trends in this space focus on:

• Increased Efficacy (lm/W): Ongoing improvements in chip design and phosphor efficiency.
• Higher CRI with Better R9: Development of phosphor systems that improve red rendering without significant efficacy loss.
• Color Tuning: Growth of tunable white products, often using multiple LED chips in a single package.
• Miniaturization & Higher Density: Packing more lumens into the same or smaller footprint for sleeker luminaire designs.
• Improved Reliability & Lifetime: Enhanced materials and packaging techniques to withstand higher temperatures and harsher environments.

This product sits within this evolving landscape, offering a reliable, standardized solution for a vast array of general lighting applications.