LED PLCC4 Yellow Light Specification - Size 3.50x2.80x1.85mm - Voltage 2.8-3.3V - Power 0.231W - English Technical Document

1. Product Overview

This technical specification document details the characteristics and requirements for a high-performance yellow light emitting diode (LED) encapsulated in a PLCC4 (Plastic Leaded Chip Carrier) package. The device is engineered using a blue semiconductor chip combined with a phosphor conversion layer to emit yellow light, a common approach for achieving specific chromaticities in solid-state lighting. With compact dimensions of 3.50mm in length, 2.80mm in width, and 1.85mm in height, this LED is designed for integration into space-constrained applications where reliable surface-mount assembly is critical. Its core design philosophy balances optical performance, thermal management, and manufacturability, positioning it as a robust component for demanding environments.

1.1 Core Advantages and Market Positioning

The primary advantage of this LED lies in its combination of a wide viewing angle and qualification for automotive standards. The 120-degree viewing angle ensures uniform illumination over a broad area, which is essential for indicator lights and ambient lighting where visibility from multiple angles is required. Furthermore, its compliance with the AEC-Q101 stress test qualification guidelines signifies that it has undergone rigorous testing for reliability under the extreme temperature cycles, humidity, and mechanical stresses typical in automotive applications. This makes it not only suitable for consumer electronics but specifically targeted at the automotive interior and exterior lighting market, including functions like switch backlighting, dashboard illumination, and exterior signal lights. The use of a standard PLCC4 footprint also ensures compatibility with existing SMT assembly lines, reducing integration costs and time-to-market for manufacturers.

2. In-Depth Technical Parameter Analysis

A thorough understanding of the electrical and optical parameters is crucial for proper circuit design and ensuring long-term reliability. The following sections break down the key specifications provided in the datasheet.

2.1 Photometric and Electrical Characteristics

The fundamental operating point for this LED is defined at a forward current (I_F) of 50mA. At this current, the forward voltage (V_F) ranges from a minimum of 2.8V to a maximum of 3.3V, with a typical value often around the midpoint. This voltage range is important for driver design, as it determines the power supply requirements and power dissipation. The luminous intensity (I_V), a measure of the light output in a specific direction, is specified between 3500 millicandelas (mcd) and 6500 mcd at 50mA. It is critical to note the stated measurement tolerance of ±10% for luminous intensity, which accounts for variations in testing equipment and conditions. The reverse current (I_R) is guaranteed to be less than 10 μA at a reverse voltage (V_R) of 5V, indicating good diode characteristics and minimal leakage.

2.2 Thermal Characteristics and Absolute Maximum Ratings

Thermal management is paramount for LED performance and lifespan. The datasheet provides two thermal resistance values: Rth_JS_real and Rth_JS_el, measured at 120 °C/W and 80 °C/W (typical) respectively. Thermal resistance (junction-to-solder point) quantifies how effectively heat is transferred from the semiconductor junction to the solder pads on the PCB. A lower value is better. The absolute maximum ratings define the limits beyond which permanent damage may occur. Key limits include a continuous forward current (I_F) of 70mA, a peak forward current (I_FP) of 100mA (under pulsed conditions with a 1/10 duty cycle), and a maximum power dissipation (P_D) of 231mW. The operating and storage temperature range is specified from -40°C to +100°C, and the maximum allowable junction temperature (T_J) is 120°C. Exceeding the junction temperature, especially over prolonged periods, will accelerate lumen depreciation and can lead to catastrophic failure.

3. Bin Range System Explanation

To manage manufacturing variances, LEDs are often sorted into performance bins. This product features binning for forward voltage (V_F) and luminous intensity (I_V) at the standard test current of 50mA. While the detailed binning table is provided in the original PDF, the principle involves grouping units based on measured V_F (e.g., G1, G2 bins as mentioned) and I_V into specific ranges. This allows designers to select components that meet tighter system tolerances for brightness consistency or voltage drop. For instance, in an array of LEDs, using devices from the same V_F and I_V bin ensures uniform brightness and current sharing, which is critical for aesthetic lighting applications. Designers should consult the bin code information when ordering to guarantee the required performance consistency for their specific application.

4. Performance Curve Analysis

The datasheet references typical optical characteristic curves. Although the specific graphs are not reproduced here, standard curves for such LEDs would typically include the relationship between forward current and forward voltage (I-V curve), the relationship between forward current and luminous intensity (I-L curve), and the variation of luminous intensity with ambient temperature. The I-V curve is non-linear, showing the diode turn-on characteristic. The I-L curve is generally linear over a range but will saturate at higher currents due to thermal effects and efficiency droop. Understanding the temperature dependence is vital; light output typically decreases as the junction temperature increases. These curves enable designers to model LED behavior under different drive conditions and thermal environments, optimizing for efficiency and longevity.

5. Mechanical and Packaging Information

The physical construction of the LED is defined by precise dimensional drawings. The PLCC4 package has a top-view outline of 3.50mm x 2.80mm, with a height of 1.85mm. The package features four leads, and a polarity mark (typically a dot or a chamfered corner) is clearly indicated to denote the cathode. The recommended soldering pad pattern (land pattern) is provided to ensure proper solder joint formation and mechanical stability during reflow. Adherence to these pad dimensions is essential for achieving good soldering yield and reliable thermal connection to the PCB. The bottom-view drawing shows the lead arrangement and the thermal pad if present, which aids in heat dissipation.

6. Soldering and Assembly Guidelines

The component is rated for all standard SMT assembly processes. Specific instructions for SMT reflow soldering are included in the document. While exact profile parameters are not detailed here, general best practices for moisture-sensitive devices (MSL Level 2) apply. This typically involves baking the components if they have been exposed to ambient conditions beyond their floor life specification before reflow to prevent popcorning or delamination. The maximum peak temperature and time above liquidus during reflow must be controlled to avoid damaging the plastic package or the internal die and wire bonds. Following the recommended reflow profile ensures electrical connectivity and long-term reliability of the solder joints.

7. Packaging and Ordering Information

For automated assembly, the LEDs are supplied on embossed carrier tapes wound onto reels. The datasheet specifies the dimensions of the carrier tape pockets, the reel diameter, and the orientation of the components on the tape. A label specification for the reel is also provided, which includes critical information such as part number, quantity, lot number, and date code. The product is shipped in moisture-barrier bags with desiccant to maintain the MSL Level 2 rating during storage and transit. This packaging format is industry-standard for high-volume SMT production, facilitating efficient pick-and-place machine handling.

8. Application Recommendations

The primary application domain is automotive lighting, both interior (e.g., instrument cluster backlighting, ambient door lighting) and exterior (e.g., side marker lights, center high-mount stop lights). Its robustness also makes it suitable for industrial indicators and consumer appliance switches. Key design considerations include: ensuring the drive current does not exceed the absolute maximum rating, implementing proper current limiting (usually with a series resistor or constant-current driver), designing the PCB layout for effective heat sinking, especially when operating at high ambient temperatures or high currents, and considering optical elements like lenses or light guides to shape the wide beam angle as needed for the application.

9. Technical Comparison and Differentiation

Compared to generic PLCC LEDs, this product's key differentiators are its formal AEC-Q101 automotive qualification and its specified wide 120-degree viewing angle. Many standard LEDs may not be tested to automotive-grade reliability standards, making this component a safer choice for applications subject to vibration, thermal cycling, and humidity. The consistent optical performance across the binning ranges also offers an advantage for applications requiring color and brightness uniformity. The combination of moderate luminous intensity with high reliability, rather than extreme brightness, is tailored for functional and aesthetic lighting where longevity is paramount.

10. Frequently Asked Questions (FAQs)

Q: What is the significance of the Moisture Sensitivity Level (MSL) 2 rating?

A: MSL 2 indicates the component can be exposed to factory floor conditions (typically ≤ 30°C/60% RH) for up to one year before it requires baking prior to reflow soldering. This provides reasonable handling flexibility but precautions are needed for long-term storage.

Q: How do I determine the appropriate series resistor for this LED?

A: Using Ohm's law: R = (V_supply - V_F) / I_F. Use the maximum V_F from the datasheet (3.3V) for a conservative design to ensure the current does not exceed 50mA even with supply voltage tolerances and component variances.

Q: Can I drive this LED with a pulse-width modulation (PWM) signal for dimming?

A: Yes, PWM dimming is an effective method. Ensure the peak current in the pulse does not exceed the absolute maximum peak current rating of 100mA, and the average power dissipation remains within the 231mW limit.

11. Practical Design and Use Cases

A typical use case is in an automotive door switch panel. Multiple LEDs of this type might be used to backlight various switch icons. The design would involve a constant-current driver circuit to ensure uniform brightness across all LEDs despite variations in forward voltage. The wide viewing angle ensures the icon is evenly illuminated from the driver's perspective. The PCB would be designed with adequate copper pours connected to the LED thermal pads to dissipate heat, especially considering the potential for high cabin temperatures. The AEC-Q101 qualification gives confidence in the component's ability to withstand the temperature swings from cold winter starts to hot summer sun.

12. Principle of Operation Introduction

This LED operates on the principle of electroluminescence in a semiconductor. Electrical current injected through the forward-biased p-n junction causes electrons and holes to recombine, releasing energy in the form of photons. The base chip emits blue light. A layer of phosphor material, deposited over the chip, absorbs a portion of this blue light and re-emits it as yellow light through a process called photoluminescence. The mix of the remaining blue light and the converted yellow light results in the perceived yellow emission. This phosphor-converted method allows for the creation of specific colors that may be difficult or inefficient to produce with direct semiconductor emission alone.

13. Industry Trends and Development Outlook

The trend in LED technology for automotive and general lighting continues towards higher efficiency (more lumens per watt), improved reliability under higher temperature operation, and tighter color consistency. There is also a move towards chip-scale packaging (CSP) for even smaller footprints. For phosphor-converted LEDs like this one, advancements focus on more stable and efficient phosphor materials that maintain color point over temperature and time. Furthermore, integration with smart drivers and controllers for dynamic lighting effects is becoming more prevalent. This component, with its automotive focus, aligns with the industry's demand for more reliable, efficient, and compact light sources for both functional and decorative purposes.