PLCC-2 Cool White LED Datasheet - 1608 Package - 2.85V @ 10mA - 120° Viewing Angle - English Technical Document

1. Product Overview

This document details the specifications for a high-performance, surface-mount Cool White LED in a PLCC-2 (Plastic Leaded Chip Carrier) package, designated as 1608 size. The device is engineered for reliability and performance in demanding environments, featuring a typical luminous intensity of 710 millicandelas (mcd) at a forward current of 10 milliamperes (mA). Its primary design focus is on automotive interior applications, where consistent light output, wide viewing angles, and robust construction are paramount.

The LED's core advantages include its compact 1608 footprint, a wide 120-degree viewing angle for excellent light dispersion, and compliance with stringent automotive and environmental standards such as AEC-Q102, RoHS, REACH, and halogen-free requirements. It is targeted at markets requiring dependable, long-life illumination in confined spaces, such as vehicle dashboard clusters, backlit switches, and general interior accent lighting.

2. In-Depth Technical Parameter Analysis

2.1 Photometric and Electrical Characteristics

The key operational parameters define the LED's performance under standard conditions (T_s=25°C). The forward current (I_F) has an operating range from 2 mA to a maximum of 20 mA, with 10 mA being the typical test condition. At this current, the typical forward voltage (V_F) is 2.85V, with a range from 2.5V to 3.75V. The primary photometric output, luminous intensity (I_V), is specified with a typical value of 710 mcd, a minimum of 560 mcd, and can reach up to 1300 mcd. The dominant chromaticity coordinates (CIE x, y) are approximately 0.3, 0.3, defining its cool white point. It is critical to note the associated measurement tolerances: ±8% for luminous flux, ±0.05V for forward voltage, and ±0.005 for chromaticity coordinates.

2.2 Absolute Maximum Ratings and Thermal Management

To ensure device longevity, operating conditions must never exceed the absolute maximum ratings. The maximum continuous forward current is 20 mA, with a power dissipation limit of 75 mW. The device can withstand a short-duration surge current (I_FM) of 50 mA for pulses ≤10 μs. The junction temperature (T_J) must not exceed 125°C, with an operating ambient temperature range of -40°C to +110°C. Thermal management is crucial; the thermal resistance from the junction to the solder point is specified as 160 K/W (real) and 140 K/W (electrical). This parameter indicates how effectively heat is transferred away from the LED chip, directly impacting light output stability and lifespan.

2.3 Reliability and Environmental Specifications

The LED is designed for robustness. It has an ESD (Electrostatic Discharge) sensitivity rating of 2 kV (Human Body Model), which is a standard level for component handling. It is qualified to the AEC-Q102 standard, confirming its suitability for automotive applications. Furthermore, it meets Corrosion Robustness Class B1, offers compliance with EU REACH regulations, and is halogen-free (Bromine <900 ppm, Chlorine <900 ppm, Br+Cl < 1500 ppm). The Moisture Sensitivity Level (MSL) is 3, meaning the package must be baked if exposed to ambient air for more than 168 hours prior to reflow soldering.

3. Performance Curve Analysis

3.1 IV Curve and Luminous Efficiency

The forward current vs. forward voltage graph shows a characteristic exponential relationship. As current increases from 0 to 25 mA, the voltage rises from approximately 2.4V to 3.2V. This curve is essential for designing the current-limiting circuitry. The relative luminous intensity vs. forward current graph demonstrates that light output increases super-linearly with current at lower levels before tending towards saturation at higher currents, emphasizing the importance of driving the LED at or near its recommended current for optimal efficiency.

3.2 Temperature Dependence

The performance graphs reveal significant temperature dependencies. The relative luminous intensity vs. junction temperature curve shows that output decreases as temperature increases. At 100°C, the intensity is roughly 60-70% of its value at 25°C. Conversely, the forward voltage has a negative temperature coefficient, decreasing by about 0.2V over the same temperature range. The chromaticity coordinates also shift with both current and temperature, which is a critical consideration for applications requiring consistent color quality.

3.3 Spectral Distribution and Beam Pattern

The relative spectral distribution graph confirms a cool white spectrum, typical of a blue LED chip with a phosphor coating. The peak is in the blue region, with a broad secondary peak in the yellow/green region from the phosphor. The radiation pattern diagram illustrates the Lambertian-like emission profile with a full width at half maximum (FWHM) of 120°, providing wide, even illumination.

3.4 Derating and Pulsed Operation

The forward current derating curve is vital for high-temperature operation. At the maximum solder pad temperature of 110°C, the permissible continuous forward current drops to 20 mA. The graph also specifies not to use currents below 2mA. The permissible pulse handling capability chart allows designers to use higher peak currents (I_F) for short durations (from 0.1 ms to 10 seconds) at various duty cycles, which is useful for multiplexing or creating brightness bursts.

4. Binning System Explanation

The LED output is categorized into bins to ensure consistency within a production lot. Two primary binning structures are provided.

4.1 Luminous Intensity Binning

Luminous intensity is sorted into groups labeled Q through B, with each group subdivided into X, Y, and Z bins representing ascending intensity ranges. For this specific part number (1608-C701 00H-AM), the possible output bins are highlighted, falling within the U and V groups. This means the typical 710 mcd part is in the upper range of the U group (U-Z: 610-710 mcd) or the lower range of the V group (V-X: 710-820 mcd). Designers must account for this range when specifying minimum brightness levels.

4.2 Chromaticity (Color) Binning

The standard cool white color bin structure defines specific quadrilaterals on the CIE 1931 chromaticity diagram. Each bin (e.g., PK0, NK0, MK0) is defined by four sets of (x, y) coordinates that form its boundaries. This ensures all LEDs within a given bin code will exhibit color coordinates within that defined area, maintaining color uniformity in an array. The provided table lists numerous bin codes and their corresponding coordinate sets.

5. Mechanical, Packaging & Assembly Information

5.1 Mechanical Dimensions and Polarity

The LED uses a standard 1608 (1.6mm x 0.8mm) PLCC-2 package. The mechanical drawing would typically show the top view, side view, and footprint. The PLCC-2 package has two leads. Polarity is indicated by a marking on the top of the device, such as a dot or a cut corner, which corresponds to the cathode (-) lead. Correct orientation is essential for circuit operation.

5.2 Recommended Soldering Pad Layout

A recommended land pattern (soldering pad) design is provided to ensure reliable solder joints and proper alignment during reflow. This pattern is slightly larger than the component's leads to facilitate good solder fillet formation. Adhering to this footprint is critical for manufacturing yield and long-term mechanical reliability.

5.3 Reflow Soldering Profile and Guidelines

The datasheet specifies a reflow soldering profile with a peak temperature of 260°C for a maximum of 30 seconds. This is a standard lead-free (Pb-free) reflow profile. The profile includes preheat, thermal soak, reflow, and cooling zones with defined ramp rates and time limits to prevent thermal shock and ensure proper solder joint formation without damaging the LED package or internal die.

5.4 Packaging Information

The LEDs are supplied on tape and reel for automated pick-and-place assembly. The packaging information details the reel dimensions, tape width, pocket spacing, and orientation of the components on the tape. This information is necessary for configuring assembly equipment.

5.5 Precautions for Use and Storage

Key precautions include: avoiding reverse voltage application, ensuring the operating conditions do not exceed absolute maximum ratings, implementing proper ESD handling procedures, and following the specified reflow profile. Storage conditions should be within the -40°C to +110°C range, and MSL-3 handling procedures must be followed if the bag is opened.

6. Application Notes and Design Considerations

6.1 Typical Application Scenarios

The primary application is automotive interior lighting. This includes illumination for instrument clusters, providing backlighting for gauges and displays. It is also ideal for backlighting various switches (power window, climate control) and for general ambient or accent lighting within the cabin. Its reliability specifications make it suitable for these harsh, temperature-cycling environments.

6.2 Circuit Design Considerations

Designers must incorporate a current-limiting resistor or a constant-current driver circuit. The resistor value can be calculated using Ohm's Law: R = (V_supply - V_F) / I_F. Using the typical V_F of 2.85V and a desired I_F of 10mA with a 5V supply, the resistor would be approximately (5 - 2.85) / 0.01 = 215 Ohms. A driver IC is recommended for applications requiring precise current control or dimming (PWM). The wide viewing angle eliminates the need for secondary optics in many diffuse lighting applications.

6.3 Thermal Management in Design

Effective heat sinking is critical for maintaining performance and longevity. The high thermal resistance value means heat does not easily escape the junction. Designers should ensure the PCB pad connected to the LED's thermal pad (if present) is adequately sized and connected to copper pours or planes to act as a heat spreader. In high-temperature ambient environments (e.g., near a car's engine electronics), the current must be derated according to the provided curve.

6.4 Sulfur Resistance Criteria

The datasheet includes a sulfur test criteria section, which is particularly relevant for automotive and industrial environments where atmospheric sulfur can corrode silver-plated components. This test verifies the LED's resistance to such environments, a key factor for long-term reliability in certain geographic locations or applications.

7. Ordering and Part Number Information

The part number system provides specific information. For the example "1608-C701 00H-AM": "1608" denotes the package size, "C701" is likely the base product code, and "00H-AM" may specify the luminous intensity bin and color bin (e.g., Cool White). The ordering information section would detail how to specify different bins or packaging options (tape and reel vs. bulk).

8. Frequently Asked Questions (FAQ)

Q: What is the difference between real and electrical thermal resistance (R_{th JS})?
A: Real thermal resistance is measured using a temperature-sensitive parameter (like forward voltage) of the LED itself. Electrical thermal resistance is often a calculated or simulated value. The real value is generally more accurate for thermal design.

Q: Can I drive this LED with a 3.3V supply without a resistor?
A: No. The forward voltage varies (2.5V-3.75V). Connecting 3.3V directly could result in excessive current if the V_F is low, potentially damaging the LED. Always use a current-limiting mechanism.

Q: How does the 120° viewing angle affect my design?
A: It provides very wide, diffuse light. It's excellent for area illumination but not for creating a focused beam. For a spotlight effect, a secondary lens would be required.

Q: Is this LED dimmable?
A: Yes, like most LEDs, it can be dimmed effectively using Pulse Width Modulation (PWM). Do not use analog voltage reduction for dimming, as it causes a significant color shift.

9. Technical Principles and Trends

9.1 Operating Principle

This is a phosphor-converted white LED. A semiconductor chip, typically made of indium gallium nitride (InGaN), emits blue light when forward biased. This blue light excites a yellow (or yellow-red) phosphor coating inside the package. The combination of the remaining blue light and the converted yellow light results in the perception of white light. The specific mix of phosphors determines the correlated color temperature (CCT), in this case, "Cool White."

9.2 Industry Trends

The trend in such components is towards higher efficiency (more lumens per watt), improved color rendering index (CRI) for better light quality, and greater miniaturization while maintaining or increasing light output. There is also a strong drive towards higher reliability standards and broader environmental compliance (e.g., lower blue light hazard, full recyclability). Integration with smart drivers for adaptive lighting is another growing area, especially in automotive applications.