SMD Low Power LED 45-21S PLCC-2 Datasheet - Package 3.5x2.8x1.9mm - Voltage 2.9-3.6V - Power 0.27W - White Light - English Technical Document

1. Product Overview

The 45-21S/XK2C series is a family of surface-mount device (SMD) low-power white light-emitting diodes (LEDs) housed in a PLCC-2 (Plastic Leaded Chip Carrier) package. This product is engineered for general illumination applications requiring a compact form factor, high efficacy, and reliable performance. The package features a white LED die and a water-clear resin lens, contributing to its high luminous output and wide viewing angle.

The core advantages of this LED series include its certification to the LM-80 standard for lumen maintenance, which assures long-term reliability and performance consistency. It is constructed with lead-free materials and is fully compliant with the RoHS (Restriction of Hazardous Substances) directive. The device utilizes ANSI (American National Standards Institute) standard binning for chromaticity and flux, ensuring color consistency and predictable light output across production batches. Its primary target markets encompass a broad range of lighting applications, including but not limited to general ambient lighting, decorative and accent lighting, entertainment lighting, status indicators, backlighting, and switch illumination.

2. Technical Parameter Deep Dive

2.1 Absolute Maximum Ratings

The device's operational limits are defined under conditions where the soldering point temperature (T_Soldering) is maintained at 25°C. Exceeding these ratings may cause permanent damage.

• Forward Current (I_F): 75 mA (Continuous)
• Peak Forward Current (I_FP): 100 mA (Permissible under pulsed conditions with a duty cycle of 1/10 and pulse width of 10ms)
• Power Dissipation (P_d): 270 mW
• Operating Temperature (T_opr): -40°C to +85°C
• Storage Temperature (T_stg): -40°C to +100°C
• Thermal Resistance (R_{th J-S}): 50 °C/W (Junction to Soldering point)
• Junction Temperature (T_j): 125 °C (Maximum)
• Soldering Temperature: For reflow soldering, a peak temperature of 260°C for 10 seconds is specified. For hand soldering, a temperature of 350°C for a maximum of 3 seconds is allowed.

Important Note: These LEDs are 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

The following parameters are measured at a standard test condition of T_Soldering = 25°C and a forward current (I_F) of 60 mA, which is the typical operating point.

• Luminous Flux (Φ): The total visible light output. The minimum value starts from 16 lumens (lm), with a maximum up to 27 lm depending on the specific bin code. A tolerance of ±11% applies to the luminous flux.
• Forward Voltage (V_F): The voltage drop across the LED when operating at 60 mA. It ranges from a minimum of 2.9 V to a maximum of 3.6 V, with a tolerance of ±0.1V for binned groups.
• Color Rendering Index (Ra or CRI): A measure of how accurately the light source reveals the colors of objects compared to a natural light source. For the mass production list provided, the minimum CRI is 80, with a tolerance of ±2.
• Viewing Angle (2θ_1/2): The angle at which the luminous intensity is half of the value at 0° (on-axis). This LED features a wide viewing angle of 120 degrees, typical.
• Reverse Current (I_R): The leakage current when a reverse bias of 5V is applied. The maximum specified value is 50 µA.

3. Binning System Explanation

The product employs a comprehensive binning system to categorize key performance parameters, enabling designers to select LEDs with precise characteristics for their application.

3.1 Product Numbering and Binning Decoding

The part number follows a specific structure: 45–21S / X K 2 C – H XX XX XX XX XXZ6 / 2T. Critical binning information is embedded within the "HXX XX XX XX XX" segment and the suffix.

• Forward Current Index (Z6): Denotes the nominal forward current is 60 mA.
• Example Decode (45-21S/KK2C-H2727L7M4B2Z6/2T):
  • KK: Indicates a Color Rendering Index (CRI) with a minimum of 80.
  • H2727: Specifies the Correlated Color Temperature (CCT). The first two digits (27) represent the minimum CCT in hundreds of Kelvin (2700K), and the last two digits (27) represent the maximum CCT (2700K), indicating a tight 2700K bin.
  • L7: Bin code for the minimum luminous flux (16-17 lm).
  • M4: Bin code for the maximum luminous flux (21-24 lm).
  • B2: Bin group for forward voltage (2.9-3.0V).

3.2 Color Rendering Index (CRI) Binning

CRI is binned using single-letter codes representing the minimum value.

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

Tolerance for CRI is ±2.

3.3 Luminous Flux Binning

Flux bins are defined by a letter-number combination (e.g., L7, M4). The table specifies the minimum and maximum luminous flux in lumens for each bin code when driven at I_F=60mA.

• L7: 16 - 17 lm
• L8: 17 - 18 lm
• L9: 18 - 19 lm
• M3: 19 - 21 lm
• M4: 21 - 24 lm
• N3: 24 - 27 lm

The overall luminous flux tolerance is ±11%.

3.4 Forward Voltage Binning

Forward voltage is grouped under a main group (e.g., B2) and further subdivided into bin codes (36 to 42). Each code corresponds to a 0.1V range.

• Group B2, Bin 36: 2.9 - 3.0 V
• Group B2, Bin 37: 3.0 - 3.1 V
• ... up to Bin 42: 3.5 - 3.6 V

The tolerance for forward voltage within a bin is ±0.1V.

3.5 Chromaticity and CCT Binning

The datasheet provides detailed chromaticity coordinate (CIE x, y) boxes on the CIE 1931 diagram for various CCTs including 2700K, 3000K, 3500K, and 4000K. Each CCT is divided into multiple bins (e.g., for 2700K: 27K-A, 27K-B, 27K-C, 27K-D, 27K-F, 27K-G). Each bin is defined by a set of four coordinate pairs that form a quadrilateral on the chromaticity chart. This allows for very precise color selection and consistency. Reference ranges are provided for the effective CCT of each main bin grouping (e.g., 27K-A/B cover 2580K-2870K).

4. Mass Production List for CRI > 80

The following table lists standard product configurations available for mass production, all with a minimum CRI of 80.

5. Application Suggestions and Design Considerations

5.1 Typical Application Scenarios

• General Lighting: Ideal for LED bulbs, tubes, and panels where high efficacy and good color rendering are required.
• Decorative & Entertainment Lighting: Suitable for accent lighting, cove lighting, and stage lighting due to its wide viewing angle and consistent color bins.
• Indicators & Switch Lights: Can be used for backlit switches, appliance status indicators, and panel illumination.
• Architectural & Retail Illumination: The high CRI options (80+ Min.) make it suitable for applications where accurate color rendition is important, such as in retail displays or art lighting.

5.2 Design Considerations

• Current Driving: Always use a constant current driver or a current-limiting resistor in series with the LED. The nominal operating point is 60mA, but the circuit must be designed to never exceed the absolute maximum rating of 75mA continuous current.
• Thermal Management: With a thermal resistance of 50°C/W from junction to solder point, proper PCB thermal design is crucial. Ensure adequate copper area (thermal pad) and possibly vias under the device to conduct heat away, especially when operating at high ambient temperatures or at maximum current. Exceeding the maximum junction temperature (125°C) will drastically reduce lifetime and can cause failure.
• Optical Design: The 120° viewing angle is inherent to the package. For applications requiring a narrower beam, secondary optics (lenses) will be necessary.
• ESD Protection: Implement ESD protection on PCB lines connected to the LED anode/cathode if the assembly environment or end-use scenario poses an ESD risk.
• Binning Selection: For applications requiring color consistency (e.g., multi-LED fixtures), specify tight CCT bins (e.g., H2727 for 2700K) and select from the same flux bin. Using the ANSI standard bins as provided ensures predictable performance.

6. Soldering and Assembly Guidelines

Adherence to the specified soldering profiles is critical to prevent damage to the plastic package and the internal wire bonds.

• Reflow Soldering (Recommended): A standard lead-free reflow profile with a peak temperature not exceeding 260°C for a duration not exceeding 10 seconds is specified. The time above 240°C should be controlled according to standard IPC/JEDEC guidelines.
• Hand Soldering: If manual soldering is unavoidable, limit the iron tip temperature to 350°C maximum and the contact time to 3 seconds per pad. Use a heatsink (e.g., tweezers) on the lead being soldered to protect the die.
• Cleaning: If cleaning is required after soldering, use solvents compatible with the plastic package. Avoid ultrasonic cleaning as it may damage the internal structure.
• Storage Conditions: Store LEDs in their original moisture-barrier bags at temperatures between -40°C and +100°C, in a low-humidity environment. If the bags have been opened and the devices are exposed to ambient humidity, they may require baking before reflow soldering to prevent "popcorn" cracking during reflow.

7. Technical Comparison and Differentiation

While direct competitor comparisons are not provided in the datasheet, key differentiating features of the 45-21S/XK2C series can be inferred:

• LM-80 Certification: This is a significant advantage for lighting manufacturers who need to comply with energy star or other certification programs requiring verified lumen maintenance data. It provides confidence in the long-term lumen output stability of the LED.
• ANSI Standard Binning: Adherence to ANSI C78.377 chromaticity bins ensures color consistency and interchangeability, which is a critical requirement in the professional lighting industry. This simplifies the design and manufacturing process for luminaire makers.
• Wide Viewing Angle (120°): The native wide beam is advantageous for applications requiring even, diffuse illumination without secondary optics, reducing system cost and complexity.
• Comprehensive Binning: The availability of detailed binning for flux, voltage, and chromaticity (with precise CIE coordinate boxes) allows for very high selectivity, enabling both cost-effective general solutions and high-performance, tightly specified applications.

8. Frequently Asked Questions (FAQ)

Q: What is the typical lifetime of this LED?
A: While the exact L70/B50 lifetime (time to 70% lumen maintenance for 50% of samples) is not stated, the LM-80 certification indicates that the manufacturer has tested and reported lumen maintenance data under controlled conditions. The actual lifetime in an application depends heavily on the operating junction temperature (T_j). Staying well below the maximum T_j of 125°C is essential for long life.

Q: Can I drive this LED at 75mA continuously?
A: The Absolute Maximum Rating for continuous forward current is 75mA. However, for reliable long-term operation and to maximize lifetime, it is strongly recommended to operate at or below the typical test current of 60mA. Operating at 75mA will generate more heat, increase the junction temperature, and accelerate lumen depreciation.

Q: How do I interpret the CCT code "H2727"?
A: In the part number, "H2727" means the LED's Correlated Color Temperature is binned to be between 2700K (min) and 2700K (max), effectively a single-step 2700K bin. "H3030" would be a 3000K bin, and "H3535" a 3500K bin. Codes like "H4040" indicate a 4000K bin.

Q: Is a heatsink required?
A> For a single LED operated at 60mA in moderate ambient conditions, the internal thermal resistance (50°C/W) and the PCB copper may be sufficient. However, for arrays of LEDs, high ambient temperatures, or operation near the maximum current, attaching the PCB to a metal core PCB (MCPCB) or an external heatsink is necessary to manage the junction temperature.

9. Operating Principle and Technology

The 45-21S LED is based on semiconductor technology. The core of the device is a chip made of InGaN (Indium Gallium Nitride) materials. When a forward voltage exceeding the diode's threshold (approximately 2.9V) is applied, electrons and holes recombine within the semiconductor's active region, releasing energy in the form of photons (light). The specific composition of the InGaN layers and the use of phosphor conversion (likely a yellow phosphor coating on a blue LED chip) determine the output color, resulting in the white light emission described. The water-clear resin encapsulant protects the chip and wire bonds while also acting as a primary lens, shaping the initial light output to achieve the 120-degree viewing angle.

10. Industry Context and Trends

The 45-21S series represents a mature and optimized product in the low-power SMD LED market. Key industry trends reflected in its specifications include:

• Demand for High Quality of Light: The availability of high CRI (80+ minimum) options addresses the growing market demand for LEDs that provide excellent color rendering, moving beyond mere efficiency to light quality.
• Standardization and Reliability: Features like LM-80 certification and ANSI binning are now industry expectations for components used in professional lighting products, underscoring a trend towards verified performance and interoperability.
• Miniaturization and Integration: The PLCC-2 package is a compact, industry-standard format that allows for high-density placement on PCBs, enabling sleek and efficient luminaire designs.
• Efficiency and Sustainability: The high luminous efficacy (implied by the flux output at 60mA), RoHS compliance, and lead-free construction align with global trends towards energy-efficient and environmentally responsible electronics.

Future developments in this segment may focus on further increasing efficacy (lumens per watt), achieving even higher CRI values (e.g., >90) with good efficiency, and improving color consistency over temperature and drive current variations.