PLCC-2 Red LED 67-21-UR0200L-AM Datasheet - 120\u00b0 Viewing Angle - 300mcd @ 20mA - 2.0V - Automotive Grade - English Technical Document

3. Absolute Maximum Ratings

These are stress limits that must not be exceeded under any conditions, even momentarily. Operation beyond these ratings may cause permanent damage.

• Surge Current (I_FM): 100 mA for pulses \u2264 10 \u00b5s with a very low duty cycle (D=0.005). This rating is relevant for withstanding brief transients.
• Reverse Voltage (V_R): The device is not designed for reverse operation. Applying a reverse voltage can instantly destroy the LED. Protection (e.g., a diode in parallel) is necessary if reverse voltage is possible in the circuit.
• Electrostatic Discharge (ESD): Rated at 2 kV (Human Body Model, HBM). This is a moderate level of ESD protection; standard ESD handling precautions should still be followed during assembly.
• Reflow Soldering Temperature: The package can withstand a peak temperature of 260\u00b0C for 30 seconds during the reflow soldering process.

4. Performance Curve Analysis

The graphs in the datasheet illustrate how key parameters change with operating conditions, providing essential data for real-world design.

4.1 Forward Current vs. Forward Voltage (I-V Curve)

This fundamental graph shows the exponential relationship between current and voltage. For this LED, at 20 mA, the voltage is typically 2.0V. The curve is essential for selecting an appropriate current-limiting resistor or designing a constant-current driver. The voltage increases non-linearly with current.

4.2 Relative Luminous Intensity vs. Forward Current

This graph shows that light output increases with current but not perfectly linearly, especially at higher currents. It helps determine the drive current needed to achieve a desired brightness level while considering efficiency.

4.3 Temperature Dependence Graphs

Three key graphs show the impact of junction temperature (T_J):

• Relative Luminous Intensity vs. T_J: Light output decreases as temperature increases. This is a critical consideration for applications in hot environments like automotive interiors.
• Relative Forward Voltage vs. T_J: The forward voltage drops linearly as temperature rises (typically -2 mV/\u00b0C for red LEDs). This property can sometimes be used for temperature sensing.
• Relative Wavelength Shift vs. T_J: The dominant wavelength shifts slightly (typically a few nanometers) with temperature, which can affect color perception in critical applications.

4.4 Forward Current Derating Curve

This is one of the most important graphs for reliability. It shows the maximum allowable continuous forward current as a function of the solder pad temperature (T_S). As the ambient/pad temperature rises, the maximum safe current decreases. For example, at the maximum solder pad temperature of 110\u00b0C, the maximum allowed continuous current is 30 mA. Designers must ensure the operating current is below this derated line based on their application's worst-case temperature.

4.5 Permissible Pulse Handling Capability

This graph defines the allowable peak pulse current for various pulse widths (t_p) and duty cycles (D). It allows the LED to be driven with short, high-current pulses to achieve very high instantaneous brightness, as long as the average power and junction temperature limits are not exceeded.

5. Binning System Explanation

Due to manufacturing variations, LEDs are sorted into performance bins. This allows customers to select parts with specific characteristics.

5.1 Luminous Intensity Binning

The LED is sorted into groups based on its minimum luminous intensity at 20mA. The datasheet lists bins from L1 (11.2-14 mcd) up to GA (18000-22400 mcd). For the 67-21-UR0200L-AM, the typical bin is centered around 300 mcd, which likely falls within the T1 (280-355 mcd) or T2 (355-450 mcd) bins. The "possible output bins" are highlighted, indicating the specific intensity range available for this part number.

5.2 Dominant Wavelength Binning

The LED is also binned by its dominant wavelength to ensure consistent color. Bins are defined in 3nm or 4nm steps. For a typical wavelength of 623 nm, the relevant bins are 2124 (621-624 nm), 2427 (624-627 nm), and 2730 (627-630 nm). The specific bin for a given order determines the exact shade of red.

6. Mechanical and Package Information

The device uses a standard PLCC-2 surface-mount package. This package has two leads and often includes a molded plastic lens. The exact dimensions, including length, width, height, and lead spacing, are provided in the mechanical drawing (Section 7 of the PDF). The recommended solder pad layout (Section 8) is crucial for achieving a reliable solder joint and proper thermal connection to the PCB. Adhering to these dimensions helps prevent tombstoning and ensures good heat sinking.

7. Soldering and Assembly Guidelines

7.1 Reflow Soldering Profile

The datasheet specifies a reflow profile with a peak temperature of 260\u00b0C for 30 seconds. This is a standard lead-free (SnAgCu) reflow profile. The preheat, soak, reflow, and cooling rates should be controlled according to standard IPC/JEDEC guidelines to avoid thermal shock and ensure proper solder joint formation.

7.2 Precautions for Use

General handling and design precautions include:

• ESD Protection: Use standard anti-static measures during handling and assembly.
• Current Control: Always operate the LED with a current-limiting device (resistor or driver). Do not connect directly to a voltage source.
• Reverse Voltage Protection: Implement circuit protection if reverse bias is possible.
• Thermal Management: Design the PCB with adequate copper area or thermal vias to dissipate heat, especially when operating at high currents or in high ambient temperatures.
• Cleaning: Use appropriate cleaning solvents that are compatible with the plastic package.

8. Application Design Considerations

8.1 Driving Circuit Design

The simplest drive method is a series resistor. The resistor value (R) is calculated as R = (V_supply - V_F) / I_F. Use the maximum V_F from the datasheet (2.75V) to ensure the current does not exceed the desired level even with a high-V_F part. For example, with a 5V supply and a target of 20 mA: R = (5V - 2.75V) / 0.020A = 112.5\u03a9 (use 110\u03a9 or 120\u03a9 standard value). The resistor power rating should be at least P = I² * R. For more stable brightness and efficiency, especially over temperature, a constant-current driver is recommended.

8.2 Thermal Design in Automotive Environments

Automotive interiors can experience extreme temperatures. The derating curve must be carefully applied. If the LED is placed near a heat source (e.g., behind a sunlit dashboard), the local PCB temperature may be significantly higher than the cabin air temperature. Thermal simulation or measurement is advised. Using a PCB with an internal ground plane connected to the LED's thermal pad (if present) greatly improves heat dissipation.

8.3 Optical Integration

The 120-degree viewing angle is suitable for wide-area illumination. For focused indicators, a secondary optic (lens or light guide) may be needed. The plastic package material may have specific refractive index properties that should be considered when designing adjacent light pipes or diffusers.

9. Technical Comparison and Differentiation

Compared to generic PLCC-2 red LEDs, the key differentiators of this part are its AEC-Q101 qualification and detailed binning information. The AEC-Q101 qualification involves a suite of stress tests (high-temperature operating life, temperature cycling, humidity resistance, etc.) that generic components do not undergo. This provides a much higher level of confidence in long-term reliability for automotive applications. The extensive binning allows for tighter control over brightness and color consistency in production runs, which is critical for automotive clusters where all warning lights must match.

10. Frequently Asked Questions (Based on Technical Parameters)

Q: Can I drive this LED at 30 mA continuously?
A: You can only drive it at 30 mA continuously if the solder pad temperature (T_S) is at or below 30\u00b0C, as per the derating curve. At a more realistic automotive interior temperature of 85\u00b0C, the maximum continuous current is derated to approximately 22-24 mA. Always consult the derating graph for your specific application temperature.

Q: What is the difference between 'Typical' and 'Binned' luminous intensity?
A: "Typical" (300 mcd) is a statistical average from the datasheet. When you order, you receive parts from a specific bin (e.g., T1: 280-355 mcd). All LEDs in your order will have a minimum intensity within that bin's range, ensuring consistency. The typical value falls within the bin range.

Q: Why is the thermal resistance given as two different values?
A: The "Real" value (160 K/W) is measured directly. The "Electrical" value (125 K/W) is calculated from the temperature dependence of the forward voltage. For conservative thermal design, always use the higher "Real" value.

Q: Is a heatsink required?
A: For continuous operation at 20 mA in a moderate environment (\u2248 25\u00b0C ambient), the power dissipation is about 40 mW (20mA * 2.0V), which is below the 82 mW maximum. A basic PCB pad is usually sufficient. However, in a high-temperature automotive environment (e.g., 85\u00b0C) or at higher currents, improving the thermal path by using a larger copper pad on the PCB or thermal vias becomes necessary to keep the junction temperature below 125\u00b0C.

11. Practical Design Case Study

Scenario: Designing a red "Door Ajar" indicator for a car's dashboard cluster. The LED will be driven by the vehicle's 12V system (nominal, but can range from 9V to 16V). The maximum expected PCB temperature in the cluster location is 85\u00b0C.

Design Steps:

1. Current Selection: Check the derating curve at T_S = 85\u00b0C. The maximum continuous current is ~22 mA. To provide margin and ensure long life, select a drive current of 15 mA.
2. Driver Circuit: Use a series resistor for simplicity. Use the maximum V_F (2.75V) and minimum supply voltage (9V during engine crank) for worst-case current calculation. R = (9V - 2.75V) / 0.015A = 416.7\u03a9. Use a standard 430\u03a9 resistor. Verify current at maximum supply (16V): I = (16V - 1.75V_{min VF}) / 430\u03a9 = 33.1 mA. This exceeds the absolute maximum rating! Therefore, a simple resistor is unsafe with this wide voltage range.
3. Revised Design: A linear constant-current regulator or a small switching LED driver is required to maintain a stable 15 mA across the 9V-16V input range. This ensures consistent brightness and protects the LED.
4. Thermal Design: Power dissipation in the LED at 15 mA is ~30 mW. Even at 85\u00b0C, this is well within limits. The thermal design focus shifts to the current regulator.
5. Bin Selection: Specify a luminous intensity bin (e.g., T1) to ensure all "Door Ajar" indicators in different cars have similar brightness.

12. Operating Principle

This is a semiconductor light-emitting diode (LED). When a forward voltage exceeding its characteristic threshold (approximately 1.8V for red) is applied, electrons and holes recombine within the semiconductor's active region (typically made of aluminum indium gallium phosphide, AlInGaP, for red). This recombination process releases energy in the form of photons (light). The specific composition of the semiconductor layers determines the wavelength (color) of the emitted light. The plastic PLCC package encapsulates the semiconductor chip, provides mechanical protection, and incorporates a molded lens that shapes the light output to achieve the 120-degree viewing angle.

13. Technology Trends

The trend in automotive LEDs is towards higher efficiency (more lumens per watt), which reduces power consumption and thermal load. This allows for brighter displays or lower energy use. There is also a move towards miniaturization of packages while maintaining or increasing light output. Furthermore, the demand for tighter color and brightness consistency (narrower binning) is increasing as automotive displays become more sophisticated and premium. The integration of driver electronics and multiple LED chips into single, smart modules is another ongoing trend, simplifying design for automotive manufacturers.