PLCC-2 White LED Specification - 3.5x2.75x1.1mm - 3.12V - 0.238W - English Technical Document

1. Product Overview

This document provides the complete technical specification for a series of white light-emitting diodes (LEDs) in a PLCC-2 (Plastic Leaded Chip Carrier) surface-mount package. These LEDs are fabricated using a blue LED chip combined with a phosphor coating to produce white light. They are designed for general-purpose lighting and indication applications requiring reliable performance and compatibility with standard automated assembly processes.

1.1 Core Features and Advantages

The primary advantages of this LED series stem from its package design and performance characteristics:

• Package: Standard PLCC-2 package ensures compatibility with a wide range of SMT assembly lines and solder processes.
• Viewing Angle: Features an extremely wide viewing angle of 120 degrees (typical), providing uniform light distribution.
• Automation Friendly: Supplied on tape and reel for high-speed pick-and-place assembly.
• Environmental Compliance: The product is RoHS compliant, meeting international environmental standards.
• Moisture Handling: Classified with a Moisture Sensitivity Level (MSL) of Level 3, requiring specific handling procedures outlined in the packaging section.

1.2 Target Applications and Market

These LEDs are suitable for a variety of indoor lighting and indication purposes. Key application areas include:

• Optical status indicators on electronic devices and control panels.
• Backlighting for indoor informational displays and signage.
• General illumination in tubular light applications.
• General-purpose decorative or functional lighting where white light is required.

Important Note: The datasheet explicitly states that this product is not suitable for flexible strip applications. Designers must consider the mechanical rigidity of the PLCC-2 package.

2. In-Depth Technical Parameter Analysis

This section provides a detailed, objective analysis of the LED's key performance parameters measured at a standard test condition of Ts=25°C.

2.1 Electro-Optical Characteristics

The table below summarizes the critical performance metrics for different correlated color temperature (CCT) variants of the product. All values are measured at a forward current (IF) of 60mA.

Table: Electrical & Optical Characteristics (Ts=25°C)

• Forward Voltage (VF): Ranges from 3.0V (Min) to 3.4V (Max), with a typical value of 3.12V. This parameter is crucial for driver circuit design to ensure proper current regulation.
• Luminous Flux (Φ): Varies slightly by CCT bin. For most white bins (E40, E50, A57, E65), the luminous flux is 26.5 lm (Typ) with a range of 26-28 lm. The warm white bin (E30) has a slightly lower typical output of 25.5 lm (24-28 lm range).
• Viewing Angle (2θ1/2): 120 degrees (Typical). This defines the angular width at which the luminous intensity drops to half of its peak value.
• Color Rendering Index (CRI): Minimum of 80, with a typical value of 81.5. This indicates good color rendering quality for general lighting.
• Thermal Resistance (RθJ-S): 55 °C/W (Typical). This is the resistance to heat flow from the semiconductor junction to the solder point. It is a key parameter for thermal management design.
• Reverse Current (IR): Maximum of 10 µA at a reverse voltage (VR) of 5V.

2.2 Absolute Maximum Ratings

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

• Power Dissipation (PD): 238 mW. The total electrical power converted to heat and light must not exceed this value.
• Forward Current (IF): 70 mA (Continuous).
• Peak Forward Current (IFP): 140 mA. This is allowed only under pulsed conditions (1/10 duty cycle, 0.1ms pulse width).
• Reverse Voltage (VR): 5 V. Exceeding this can cause breakdown.
• Electrostatic Discharge (ESD): 2000 V (Human Body Model). While the yield is over 90% at this level, ESD protection during handling is still required.
• Temperature Ranges:
  • Operating (TOPR): -40°C to +85°C.
  • Storage (TSTG): -40°C to +100°C.
  • Junction (TJ): 110°C (Maximum). The actual junction temperature during operation must be calculated and kept below this limit.

3. Binning System Explanation

The LEDs are sorted (binned) based on key parameters to ensure consistency within a production lot. This allows designers to select parts that meet specific application requirements.

3.1 Forward Voltage and Luminous Flux Binning

At IF=60mA, LEDs are categorized into bins for forward voltage (VF) and luminous flux (Φ).

• Forward Voltage Bins (H1, H2, I1, I2): These represent voltage ranges: 3.0-3.1V, 3.1-3.2V, 3.2-3.3V, and 3.3-3.4V respectively.
• Luminous Flux Bin (QIA): This bin corresponds to a luminous flux range of 26-28 lumens.

3.2 Correlated Color Temperature (CCT) Binning

The white light is defined by its chromaticity coordinates on the CIE 1931 diagram. The datasheet provides specific bins with their respective coordinate boundaries (x1,y1 to x4,y4) that form a quadrilateral on the diagram.

• E30: Warm White (2780-3110K)
• E40: Neutral White (3770-4330K)
• E50: Cool White (4660-5360K)
• A57: ANSI Cool White (5350-6050K)
• E65: Daylight White (6050-6950K)

The typical measurement tolerance for color coordinates is ±0.005.

4. Performance Curve Analysis

Graphical data provides insight into the device's behavior under varying conditions.

4.1 Forward Voltage vs. Forward Current (IV Curve)

The provided curve shows the relationship between forward voltage (VF) and forward current (IF). It is a non-linear curve typical of a diode. The voltage increases with current, and the slope represents the dynamic resistance of the LED. Designers use this curve to select an appropriate driving voltage/current to achieve desired brightness while staying within power limits.

4.2 Relative Luminous Intensity vs. Forward Current

This curve illustrates how the light output (relative intensity) changes with the applied forward current. Typically, the output increases with current but may saturate or become less efficient at very high currents due to thermal effects and droop. This graph is essential for determining the optimal operating current for efficiency and longevity.

5. Mechanical and Package Information

5.1 Package Dimensions and Drawings

The LED is housed in a PLCC-2 package. Key dimensions (all in millimeters, tolerance ±0.05mm unless noted) include:

• Overall Length: 3.50 mm
• Overall Width: 2.75 mm
• Overall Height: 1.10 mm
• Lead Dimensions: Specific pad widths and spacings are detailed in the soldering pattern diagram (Fig. 1-5).

5.2 Polarity Identification and Soldering Pattern

Clear polarity marking is critical for correct installation. The cathode (C, negative) is identified on the package. The datasheet includes a recommended soldering pad land pattern (Fig. 1-5) for PCB design to ensure proper solder joint formation and mechanical stability during reflow.

6. Soldering and Assembly Guidelines

6.1 SMT Reflow Soldering Instructions

The LED is suitable for all standard SMT assembly processes. However, due to its MSL Level 3 rating, specific precautions are necessary:

• Moisture Sensitivity: After the sealed moisture barrier bag is opened, the components must be mounted within 168 hours (7 days) when stored at conditions ≤30°C/60% RH.
• Baking: If the exposure time is exceeded, the components must be baked before use to remove absorbed moisture and prevent "popcorn" cracking during reflow. Standard baking profiles apply (e.g., 125°C for a specified time).
• Reflow Profile: A standard lead-free (or leaded) reflow profile with a peak temperature not exceeding the maximum ratings for the device (refer to package and junction temperature limits) should be used. The thermal mass of the PCB and components must be considered.

6.2 General Handling Precautions

• Avoid mechanical stress on the LED lens and leads.
• Use ESD-safe practices during handling and assembly.
• Do not touch the lens with bare hands to avoid contamination.
• Store in the original moisture-resistant packing until ready for use.

7. Packaging and Ordering Information

7.1 Packaging Specification

The LEDs are supplied in industry-standard packaging for automated assembly.

• Carrier Tape: Dimensions for the embossed carrier tape that holds individual LEDs are specified, including pocket size, pitch, and tape width.
• Reel Dimension: Specifications for the reel onto which the carrier tape is wound, including reel diameter and hub size.
• Label Specification: The format for the reel label, which typically includes part number, quantity, lot code, and date code.

7.2 Moisture-Resistant Packing and Carton

The reels are packaged in a sealed moisture barrier bag with a desiccant and humidity indicator card to maintain the MSL rating. These bags are then packed in cardboard boxes for shipment.

8. Application Design Considerations

8.1 Driver Circuit Design

Given the forward voltage characteristics (VF typ. 3.12V, max 3.4V at 60mA), a constant current driver is strongly recommended over a constant voltage source. This ensures stable light output and protects the LED from thermal runaway. The driver should be designed to limit the maximum current to 70mA continuous.

8.2 Thermal Management

With a thermal resistance of 55 °C/W, effective heat sinking is important, especially when operating at higher currents or in elevated ambient temperatures. The PCB layout should provide adequate copper area (thermal pads) connected to the LED's solder points to dissipate heat. The maximum junction temperature (110°C) must not be exceeded. The actual junction temperature can be estimated using the formula: Tj = Ts + (RθJ-S * PD), where Ts is the solder point temperature and PD is the power dissipation (VF * IF).

8.3 Optical Design

The 120-degree viewing angle makes these LEDs suitable for applications requiring wide, diffuse illumination rather than a focused beam. For applications requiring more directional light, secondary optics (lenses) would be necessary.

9. Technical Comparison and Differentiation

While many PLCC-2 white LEDs exist on the market, this series differentiates itself through a combination of parameters:

• Balanced Performance: It offers a good balance of luminous flux (26-28 lm), CRI (>80), and wide viewing angle at a standard 60mA drive current.
• Comprehensive Binning: The detailed voltage, flux, and multi-CCT binning provide designers with the flexibility to select parts for color- and brightness-critical applications.
• Clear Application Guidance: The explicit warning against use in flexible strips is a critical differentiator that prevents field failures due to mechanical stress.

10. Frequently Asked Questions (Based on Technical Parameters)

10.1 What is the recommended operating current?

The datasheet characterizes the LED at IF=60mA, and this is a typical operating point. The absolute maximum continuous current is 70mA. For optimal longevity and efficiency, operating at or below 60mA is advisable. The performance vs. current curve should be consulted for specific brightness requirements.

10.2 How do I select the correct CCT bin?

Choose the CCT bin (E30, E40, E50, A57, E65) based on the desired "color" of white light for your application—warmer (yellowish) to cooler (bluish). The chromaticity coordinate bins ensure color consistency within a selected group.

10.3 Can I drive this LED with a 3.3V power supply?

Directly connecting to a 3.3V source is risky. The typical forward voltage is 3.12V, but it can be as high as 3.4V. A 3.3V source may not reliably turn on all units, especially those in higher VF bins, leading to inconsistent brightness. A constant current driver circuit is the correct solution.

10.4 What are the consequences of exceeding the moisture exposure time?

If the MSL Level 3 exposure limit (168 hours) is exceeded without proper baking, absorbed moisture can rapidly vaporize during the high-temperature reflow soldering process. This can cause internal delamination or "popcorn" cracking of the plastic package, leading to immediate or latent failure.

11. Practical Design and Usage Case

Case: Designing a Status Indicator Panel

An engineer is designing a control panel that requires multiple bright, uniform white status indicators. The panel operates in an indoor environment at room temperature.

• Component Selection: This PLCC-2 LED is chosen for its wide viewing angle (ensuring visibility from various angles), SMT compatibility (easing assembly), and good brightness.
• Circuit Design: A simple constant-current circuit is designed using a current-limiting resistor in series with a voltage regulator. The resistor value is calculated based on the supply voltage (e.g., 5V), the target current (60mA), and the maximum expected VF (3.4V): R = (Vsupply - VF_max) / IF = (5 - 3.4) / 0.06 ≈ 26.7Ω. A 27Ω resistor is selected.
• Thermal Management: Since the panel operates at low duty cycle and ambient temperature, and the power per LED is low (~0.2W), the standard PCB copper pour is sufficient for heat dissipation. The junction temperature is verified to be well within limits.
• Result: The final product features reliable, consistently bright indicators that are easy to manufacture in volume.

12. Operating Principle

This white LED operates on the principle of phosphor conversion. The core component is a semiconductor chip that emits blue light when electrical current passes through it (electroluminescence). This blue light is then directed onto a layer of phosphor material deposited inside the package. The phosphor absorbs a portion of the blue light and re-emits it as light of longer wavelengths (yellow, red). The combination of the remaining blue light and the converted yellow/red light is perceived by the human eye as white light. The specific mix of phosphors determines the correlated color temperature (CCT) and color rendering index (CRI) of the emitted white light.

13. Technology Trends

The general trend in SMD LED technology, including devices like this PLCC-2 type, continues to focus on several key areas:

• Increased Efficiency (lm/W): Ongoing improvements in chip design, phosphor efficiency, and package architecture aim to deliver more light output (lumens) for the same electrical input power (watts).
• Improved Color Quality and Consistency: Advancements in phosphor technology and tighter binning processes lead to higher CRI values and more precise color point control, meeting the demands of high-quality lighting applications.
• Enhanced Reliability and Lifetime: Research into better packaging materials, die attach methods, and thermal management extends the operational lifetime and maintains light output over time (lumen maintenance).
• Miniaturization and Integration: While PLCC-2 remains a standard, there is a trend towards smaller package footprints and chip-scale packages (CSP) for space-constrained applications, as well as integrated modules combining multiple LEDs and drivers.