Red LED PLCC4 3.5x2.8x1.85mm - Forward Voltage 1.9-2.5V - Power 125mW - Luminous Intensity 1500-2800mcd - AEC-Q102 Qualified

1. Product Overview

This high-brightness red LED is based on AlGaInP semiconductor technology and packaged in a compact PLCC4 form factor measuring 3.50mm x 2.80mm x 1.85mm. Designed for demanding automotive interior and exterior lighting applications, the device complies with the AEC-Q102 stress test qualification standard, ensuring robust reliability under harsh operating conditions. The LED delivers a dominant wavelength range of 627.5nm to 635nm with a typical viewing angle of 120°, providing uniform illumination over a wide area. With a forward voltage of 1.9V to 2.5V at 50mA and luminous intensity from 1500mcd to 2800mcd, it balances efficiency and brightness for various signal and indicator lighting needs.

2. Technical Parameter Analysis

2.1 Electrical and Optical Characteristics

At a test current of 50mA and ambient temperature of 25°C, the electrical and optical parameters are defined as follows:

• Forward Voltage (VF): minimum 1.9V, typical value not provided, maximum 2.5V. Measurement tolerance is ±0.1V.
• Reverse Current (IR): at reverse voltage 5V, maximum 10µA, ensuring low leakage.
• Dominant Wavelength (λD): 627.5nm to 635nm, covering deep red region. Measurement tolerance ±0.005nm.
• Luminous Intensity (IV): 1500mcd to 2800mcd, with ±10% measurement tolerance.
• Viewing Angle (2θ1/2): 120° typical, providing wide dispersion suitable for indicator and backlighting applications.
• Thermal Resistance (Rth JS real): 160°C/W typical, 180°C/W maximum (junction to solder). Electrical measurement method yields 80°C/W typical, 90°C/W maximum.

2.2 Absolute Maximum Ratings

The device must not be operated beyond the following limits at 25°C solder point temperature:

• Power Dissipation: 175mW
• Forward Current: 70mA (continuous), 100mA peak (1/10 duty cycle, 10ms pulse width)
• Reverse Voltage: 5V
• ESD (HBM): 2000V
• Operating Temperature: -40°C to +100°C
• Storage Temperature: -40°C to +100°C
• Junction Temperature: 120°C

Care should be taken that power dissipation does not exceed the absolute maximum rating. The maximum current in operation should be determined after measuring package temperature to ensure junction temperature remains below the maximum limit.

3. Binning System

3.1 Forward Voltage Bins (IF=50mA)

The forward voltage is categorized into six bins: B2 (1.9-2.0V), C1 (2.0-2.1V), C2 (2.1-2.2V), D1 (2.2-2.3V), D2 (2.3-2.4V), E1 (2.4-2.5V).

3.2 Luminous Intensity Bins

Intensity bins are defined as M2 (1500-1800mcd), N1 (1800-2300mcd), N2 (2300-2800mcd).

3.3 Wavelength Bins

Dominant wavelength bins: F2 (627.5-630nm), G1 (630-632.5nm), G2 (632.5-635nm).

These bins allow customers to select devices with tight tolerances for consistent color and brightness in mass production. The bin code on the product label indicates the exact combination of VF, IV, and wavelength ranks.

4. Performance Curves

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

The forward voltage increases non-linearly with current. At 1.9V the current is near zero; at 2.5V the current reaches approximately 60mA. The curve indicates a typical forward voltage around 2.2V at 50mA.

4.2 Relative Luminous Intensity vs. Forward Current

Relative intensity increases almost linearly with forward current up to 60mA. At 50mA the relative intensity is approximately 100% (reference point). Dimming by current reduction is effective but note that chromaticity shift is minimal in this range.

4.3 Junction Temperature Effects

As junction temperature rises from -40°C to 120°C, relative luminous intensity decreases by about 20% at 120°C compared to room temperature. The forward voltage shift (ΔVF) is negative with temperature, decreasing by approximately 0.2V over the full range. Dominant wavelength shifts slightly (about 4-5nm) to longer wavelengths as temperature increases. These characteristics are important for thermal management in high-temperature automotive environments.

4.4 Solder Temperature Derating

Maximum forward current must be derated as solder point temperature rises. At 100°C solder temperature, the allowable current drops to about 20mA from 70mA at 25°C.

4.5 Radiation Pattern

The radiation diagram shows a typical lambertian pattern with half-power angle of ±60°, confirming the wide 120° viewing angle. The intensity is uniform across the emission cone.

4.6 Spectrum Distribution

The spectral distribution peaks at approximately 630nm with a full width at half maximum (FWHM) of about 20-25nm. No secondary emission is observed, ensuring color purity.

5. Mechanical and Packaging Information

5.1 Package Dimensions

The LED is encapsulated in a PLCC4 package with dimensions: length 3.50mm, width 2.80mm, height 1.85mm. The package has a polarity mark (dot) on top view indicating cathode. Bottom view shows four terminals: pad 1 (cathode), pad 2 (anode), pad 3 (anode), pad 4 (cathode) according to the polarity diagram. Polarity is also indicated by a chamfer on the package corner.

5.2 Recommended Soldering Pad Pattern

The recommended PCB land pattern includes four pads: two inner anode pads (each 2.20mm x 0.80mm) and two outer cathode pads (each 2.60mm x 0.80mm). The overall footprint is 4.60mm x 1.60mm with 0.70mm spacing between pads. Tolerances are ±0.05mm unless otherwise noted.

5.3 Carrier Tape and Reel

Devices are supplied in 8mm wide carrier tape with 4mm pitch sprocket holes. Tape dimensions: width 8.00mm, pocket pitch 4.00mm, cavity size 3.50mm x 2.80mm x 1.85mm. Each reel (330mm diameter) contains 2000 pieces. The reel hub is 60mm inner diameter with 13.6mm hub hole.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Profile

The recommended reflow profile (lead-free) is as follows:

• Average ramp-up rate: 3°C/s max from Tsmin (150°C) to Tp
• Preheat: 150°C to 200°C for 60-120 seconds
• Time above 217°C (TL): 60 seconds max
• Peak temperature (Tp): 260°C for 10 seconds max
• Cooling ramp-down: 6°C/s max
• Time from 25°C to peak: 8 minutes max

Reflow soldering should not exceed two times. If more than 24 hours elapse between two solderings, the LEDs may absorb moisture and be damaged. Do not apply mechanical stress during heating.

6.2 Hand Soldering

If manual soldering is necessary, use a soldering iron at less than 300°C for less than 3 seconds, and only once.

6.3 Storage and Moisture Sensitivity

Moisture sensitivity level is Level 2. Before opening the aluminum bag, store at ≤30°C and ≤75% RH for up to one year from date of manufacture. After opening, use within 24 hours at ≤30°C and ≤60% RH. If storage conditions are exceeded, baking at 60±5°C for more than 24 hours is required.

7. Packaging and Ordering Information

The product is packaged in reel quantities of 2000 pieces. Each reel is sealed in a moisture barrier bag with a desiccant and humidity indicator card. The outer cardboard box contains multiple reels. Each reel and bag is labeled with part number, specification number, lot number, bin code, quantity, and date code. The bin code encodes the specific ranks of luminous intensity, chromaticity (wavelength), and forward voltage.

8. Application Recommendations

8.1 Typical Applications

Automotive interior lighting (dashboard indicators, ambient lighting), exterior lighting (brake lights, turn signals, tail lights), switches, and general signal indication. The wide viewing angle and high brightness make it suitable for edge-lit panels and backlighting.

8.2 Design Considerations

• Thermal Management: Given the thermal resistance of 160°C/W, adequate heat sinking is necessary when driving near maximum current. Maintain solder point temperature below 100°C to ensure junction temperature stays under 120°C.
• Current Limiting: Always use a series resistor or constant current driver to prevent overcurrent. Small voltage variations cause large current changes due to the steep I-V curve.
• ESD Protection: The device is rated 2kV HBM. Use appropriate ESD precautions during handling and assembly.
• Sulfur and Halogen Restrictions: Keep sulfur content below 100ppm, bromine below 900ppm, chlorine below 900ppm, and combined below 1500ppm to avoid corrosion and lumen degradation.
• Volatile Organic Compounds (VOCs): Avoid adhesives or potting compounds that outgas organic vapors which can penetrate the silicone encapsulant and cause discoloration.
• Cleaning: Isopropyl alcohol is recommended for cleaning after soldering. Do not use ultrasonic cleaning as it may damage the LED.

9. Technology Comparison

Compared to conventional red LEDs based on GaAsP or GaP, this AlGaInP device offers significantly higher luminous efficacy (typical 1500-2800mcd at 50mA) and better temperature stability. The PLCC4 surface-mount package with a wide 120° viewing angle provides design flexibility for space-constrained automotive modules. The AEC-Q102 qualification ensures it meets stringent automotive reliability requirements, including thermal shock, life test, and high humidity operation.

10. Frequently Asked Questions

Q: What is the maximum recommended operating current for this LED?
A: The absolute maximum continuous forward current is 70mA, but for reliable long-life operation, derating must be applied based on ambient temperature and thermal management. Typically, 50mA is a safe nominal current with adequate heat sinking.

Q: Can this LED be driven by a PWM signal?
A: Yes, the LED can be pulse-width modulated for dimming. Ensure peak current does not exceed 100mA and the duty cycle is limited to keep average power below 175mW.

Q: What is the color consistency across different brightness bins?
A: The wavelength bins are independent of intensity bins. Customers should select both wavelength and intensity bins for consistent color and brightness. The typical wavelength shift with current and temperature is minimal within the specified range.

11. Practical Use Cases

Case 1: Automotive Rear Combination Lamp
Designers used 18 of these red LEDs in a 3-series 6-parallel configuration for a tail light. Each string was driven at 40mA with a constant current IC. Thermal simulation showed junction temperature stayed below 85°C under ambient 50°C. The wide viewing angle eliminated the need for secondary optics.

Case 2: Interior Ambient Lighting
For a center console accent light, two LEDs were placed behind a light guide. The 120° emission angle provided uniform illumination along the guide. The low forward voltage allowed direct driving from a 3.3V rail with a 22Ω resistor per LED, achieving 1500mcd per LED at 30mA.

12. Operational Principle

The red LED uses AlGaInP (Aluminum Gallium Indium Phosphide) as the active layer material, which is a direct bandgap semiconductor. When forward-biased, electrons from the n-type layer recombine with holes in the p-type layer, releasing energy in the form of photons. The bandgap energy of AlGaInP can be tuned by adjusting the Indium composition to emit in the red region (around 630nm). The multi-quantum well structure enhances recombination efficiency, resulting in high luminous intensity even at moderate currents. The transparent substrate and optimized chip design improve light extraction.

13. Development Trends

The trend in red LEDs for automotive applications is toward higher efficiency (lm/W) and smaller package sizes to enable more compact lighting designs. Improvements in AlGaInP epitaxial growth and chip shaping continue to push luminous efficacy beyond 100 lm/W for red. Additionally, integration of ESD protection within the package is becoming common. The adoption of AEC-Q102 and similar standards ensures that these LEDs can withstand harsh automotive environments. Future developments may include full-spectrum tuneable red-amber-green modules using multiple chips in a single PLCC package.