PLCC-2 Red LED Datasheet - 120° Viewing Angle - 3550mcd @ 50mA - 2.2V - Automotive Grade - English Technical Document

1. Product Overview

This document details the specifications for a high-performance, surface-mount red LED in a PLCC-2 package. The device is engineered primarily for demanding automotive interior applications, offering a combination of high luminous output, wide viewing angle, and robust reliability. Its core advantages include compliance with stringent automotive standards like AEC-Q102, excellent sulfur resistance (Class A1), and adherence to environmental directives such as RoHS, REACH, and Halogen-Free requirements. The target market is automotive electronics, specifically for interior ambient lighting, backlighting for switches, and other indicator functions where reliability and consistent performance under harsh conditions are paramount.

2. In-Depth Technical Parameter Analysis

2.1 Photometric and Electrical Characteristics

The LED's key performance metrics are defined under standard test conditions. The typical forward voltage (V_F) is 2.20V at a forward current (I_F) of 50mA, with a specified range from 1.75V (Min) to 2.75V (Max). The luminous intensity (I_V) is rated at 3550 millicandelas (mcd) typical under the same 50mA condition, with a minimum of 2800 mcd and a maximum of 5600 mcd. The dominant wavelength (λ_d) is centered at 615nm, defining its red color, with a tolerance of ±1nm. The device features a very wide 120-degree viewing angle (φ), ensuring good visibility from off-axis positions. The absolute maximum forward current is 70mA, and the device is not designed for reverse voltage operation.

2.2 Thermal and Reliability Ratings

Thermal management is critical for LED longevity. The junction-to-solder thermal resistance (R_{th JS}) has two values: 85 K/W (typical, real) and 60 K/W (typical, electrical). The maximum permissible junction temperature (T_J) is 125°C, while the operating temperature range (T_opr) spans from -40°C to +110°C. The device can withstand a reflow soldering temperature of 260°C for up to 30 seconds. For electrostatic discharge (ESD) protection, it is rated for 2kV (Human Body Model). The power dissipation (P_d) is limited to 192 mW.

3. Binning System Explanation

To ensure color and brightness consistency in production, LEDs are sorted into bins.

3.1 Luminous Intensity Binning

The luminous intensity is categorized into a detailed alphanumeric binning structure. Bins range from L1 (11.2-14 mcd) up to high-output bins like GA (18000-22400 mcd). The specific device covered in this datasheet, based on its typical rating of 3550 mcd, would fall into the CA bin (2800-3550 mcd). This system allows designers to select parts with tightly controlled brightness levels for uniform lighting applications.

3.2 Dominant Wavelength Binning

The dominant wavelength, which determines the perceived color, is also binned. The bins are defined by four-digit codes representing the minimum and maximum wavelength in nanometers. For example, bin '1215' covers wavelengths from 612nm to 615nm. The device's typical 615nm wavelength places it in the '1518' bin (615-618 nm) or potentially the '1215' bin, depending on the specific production lot. This precise binning is crucial for applications requiring specific color points or color mixing.

4. Performance Curve Analysis

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

The provided graph shows the relationship between forward current and forward voltage at 25°C. The curve is characteristic of a diode, showing an exponential increase in current once the forward voltage exceeds a threshold (around 1.7V for this LED). This curve is essential for designing the current-limiting circuitry to ensure stable operation.

4.2 Thermal Characteristics

Several graphs illustrate performance variation with temperature. The Relative Luminous Intensity vs. Junction Temperature graph shows that light output decreases as temperature increases, a typical behavior for LEDs. The Relative Forward Voltage vs. Junction Temperature graph demonstrates that V_F has a negative temperature coefficient, decreasing linearly with rising temperature. The Dominant Wavelength vs. Junction Temperature and Relative Wavelength vs. Junction Temperature graphs show a slight shift in wavelength (typically a few nanometers) with temperature, which is important for color-critical applications.

4.3 Spectral Distribution and Radiation Pattern

The Relative Spectral Distribution graph confirms the monochromatic red output, with a peak around 615nm and very little emission in other parts of the spectrum. The Typical Diagram Characteristics of Radiation (not fully detailed in the excerpt) would typically show the spatial distribution of light, illustrating the 120° viewing angle where intensity falls to half of its peak value.

4.4 Derating and Pulse Handling

The Forward Current Derating Curve is critical for reliability. It shows the maximum allowable continuous forward current as a function of the solder pad temperature (T_S). For example, at a T_S of 110°C, the maximum I_F is derated to 55mA. The Permissible Pulse Handling Capability graph defines the maximum permissible non-repetitive or repetitive pulse current for various pulse widths (t_p) and duty cycles (D), which is useful for PWM dimming or transient conditions.

5. Mechanical and Package Information

The LED uses a standard PLCC-2 (Plastic Leaded Chip Carrier) surface-mount package. While the exact mechanical dimensions (length, width, height) are referenced in section 7 of the datasheet but not provided in the excerpt, this package type is widely used and allows for automated pick-and-place assembly. The device will have clear anode and cathode markings for correct PCB orientation. A recommended soldering pad layout is provided to ensure proper solder joint formation and thermal dissipation during reflow.

6. Soldering and Assembly Guidelines

The device is suitable for reflow soldering processes. The specified profile allows for a peak temperature of 260°C for a maximum of 30 seconds. Designers must adhere to this profile to prevent thermal damage to the plastic package or the semiconductor die. Precautions for use likely include standard handling procedures to avoid mechanical stress on the leads, protection from moisture (MSL Level 2), and avoidance of excessive electrostatic discharge. Proper storage conditions would align with the specified storage temperature range of -40°C to +110°C in a dry environment.

7. Packaging and Ordering Information

The part number for this device is 57-21R-UR0501H-AM. The ordering information and packaging details (e.g., tape and reel specifications, quantity per reel) are covered in sections 6 and 10 of the datasheet. The part number structure may encode information such as color (R for Red), package type, and possibly binning codes, allowing for precise ordering of the required performance grade.

8. Application Recommendations

8.1 Typical Application Scenarios

The primary application is automotive interior lighting. This includes dashboard backlighting, ambient footwell lighting, backlighting for control buttons and switches, and status indicators on center consoles. Its AEC-Q102 qualification and sulfur robustness make it specifically suitable for the harsh environment inside a vehicle, which can involve high temperatures, thermal cycling, and exposure to corrosive gases.

8.2 Design Considerations

When designing with this LED, engineers must consider several factors:
1. Current Drive: A constant current driver is recommended to maintain stable light output, as LED brightness is a function of current, not voltage. The circuit must limit I_F to 50mA for typical operation and never exceed 70mA.
2. Thermal Management: The PCB layout must facilitate heat dissipation from the solder pads to prevent the junction temperature from exceeding 125°C, especially in high ambient temperature environments. Using the recommended pad layout and possibly thermal vias is advised.
3. ESD Protection: Although rated for 2kV HBM, implementing basic ESD protection on the input lines is good practice, especially during handling and assembly.
4. Optical Design: The 120° viewing angle provides wide emission. For focused light, secondary optics (lenses) may be required.

9. Technical Comparison and Differentiation

Compared to standard commercial-grade LEDs, this device's key differentiators are its automotive-grade reliability certifications. The AEC-Q102 qualification involves a suite of rigorous tests for high-temperature operation, thermal shock, moisture resistance, and longevity. The Class A1 sulfur robustness rating indicates superior resistance to sulfur-containing atmospheres, which is a common failure mode in automotive environments due to certain rubber and lubricant compounds. The wide operating temperature range (-40°C to +110°C) exceeds that of typical consumer LEDs, ensuring functionality in all climatic conditions a vehicle may encounter.

10. Frequently Asked Questions (Based on Technical Parameters)

Q: Can I drive this LED with a 3.3V supply directly?
A: No. The typical forward voltage is 2.2V, but it can be as low as 1.75V. Connecting it directly to a 3.3V source without a current-limiting resistor or driver would cause excessive current to flow, potentially exceeding the absolute maximum rating of 70mA and destroying the LED. A series resistor or constant-current driver is mandatory.

Q: How does the light output change if I drive it at 30mA instead of 50mA?
A: Referencing the Relative Luminous Intensity vs. Forward Current graph, the output is not linearly proportional to current. At 30mA, the relative intensity is approximately 0.6 (or 60%) of its value at 50mA. Therefore, the luminous intensity would be roughly 2130 mcd (0.6 * 3550 mcd).

Q: Is this LED suitable for PWM dimming?
A: Yes, LEDs are ideal for PWM dimming. The Permissible Pulse Handling Capability graph should be consulted to ensure the chosen peak current, pulse width, and duty cycle are within safe operating limits. Typically, for dimming frequencies above 100Hz, the graph allows for pulse currents higher than the DC maximum, but average power must still be managed.

11. Practical Design and Usage Case

Case: Designing an Automotive Switch Backlight. A designer needs to illuminate a row of 5 push-button switches on a center console. Each switch requires even, low-level red illumination. The designer selects this LED for its reliability. Using a 12V automotive supply, a circuit is designed where each LED is driven by a dedicated constant-current regulator set to 50mA. The LEDs are placed on the PCB behind a light guide to distribute the 120° beam evenly across the switch icon. Thermal analysis confirms that in the worst-case cabin temperature of 85°C, the solder pad temperature remains below 100°C, keeping the forward current within the derated limit from the graph, thus ensuring long-term reliability.

12. Operating Principle Introduction

Light Emitting Diodes (LEDs) are semiconductor devices that emit light through electroluminescence. When a forward voltage is applied across the p-n junction, electrons from the n-type material recombine with holes from the p-type material in the active region. This recombination process releases energy in the form of photons (light). The specific wavelength (color) of the emitted light is determined by the energy bandgap of the semiconductor materials used in the construction of the LED chip. In this red LED, materials like Aluminum Gallium Arsenide (AlGaAs) or similar compounds are typically used to produce photons with a wavelength around 615nm, which the human eye perceives as red.

13. Technology Trends and Developments

The trend in automotive LED lighting is towards higher efficiency (more lumens per watt), which reduces power consumption and thermal load. There is also a move towards smaller package sizes with higher power density, enabling more compact and stylish designs. Furthermore, the integration of control electronics directly with the LED package (e.g., LED drivers, protection circuits) is becoming more common, simplifying the system design for engineers. The demand for even broader color gamuts and higher color rendering indices (CRI) for interior ambient lighting is also pushing advancements in phosphor technology and multi-chip designs, although this particular device is a monochromatic red LED. Reliability standards continue to evolve, with longer lifetime requirements and testing for new environmental stressors.