Red LED 3.50x2.80x1.85mm PLCC4 - Forward Voltage 2.4V - Power Dissipation 196mW - Wavelength 621nm - Technical Specifications

1. Product Overview

1.1 General Description

This product is a high-performance red light-emitting diode (LED) fabricated with AlGaInP epitaxial layers on a substrate. It is housed in a standard PLCC-4 package measuring 3.50 mm × 2.80 mm × 1.85 mm. The device is designed for surface mount technology (SMT) assembly and is qualified to automotive grade standards (AEC-Q101), making it suitable for demanding applications such as automotive interior lighting and switches. The LED emits a deep red color with a dominant wavelength centered around 621 nm and offers a very wide viewing angle of 120°.

1.2 Features

• PLCC-4 package (3.50 mm × 2.80 mm × 1.85 mm)
• Extremely wide viewing angle (120°)
• Suitable for all SMT assembly and soldering processes
• Available on tape and reel (2000 pcs/reel)
• Moisture sensitivity level: Level 2 (per IPC/JEDEC J-STD-020)
• Compliance with RoHS and REACH directives
• Qualified according to AEC-Q101 stress test qualification for automotive-grade discrete semiconductors
• ESD withstand capability: 2000 V (HBM), with >90% yield

1.3 Applications

• Automotive interior lighting (dome lights, reading lights, ambient lighting)
• Switches and indicator lights

2. Technical Parameters

2.1 Electrical and Optical Characteristics (at Ts = 25°C, IF = 50 mA)

The following table summarizes the key electrical and optical parameters measured at a forward current of 50 mA (unless otherwise noted):

The forward voltage is measured with an allowance tolerance of ±0.1 V, and luminous intensity tolerance is ±10%. The color coordinates (dominant wavelength) tolerance is ±0.5 nm.

2.2 Absolute Maximum Ratings

The device must not be operated beyond the absolute maximum ratings listed below. Exceeding these limits may cause permanent damage.

2.3 Bin Ranges for Forward Voltage, Luminous Intensity, and Dominant Wavelength

To ensure consistent performance, the LEDs are binned at a test current of 50 mA into the following categories:

• Forward Voltage (V_F) bins: C1 (2.0–2.1 V), C2 (2.1–2.2 V), D1 (2.2–2.3 V), D2 (2.3–2.4 V), E1 (2.4–2.5 V), E2 (2.5–2.6 V), F1 (2.6–2.7 V), F2 (2.7–2.8 V).
• Luminous Intensity (I_V) bins: N1 (1800–2300 mcd), N2 (2300–2800 mcd), O1 (2800–3500 mcd).
• Dominant Wavelength (λ_d) bins: D2 (617.5–620 nm), E1 (620–622.5 nm), E2 (622.5–625 nm).

2.4 Thermal Characteristics

The thermal resistance from junction to solder point (R_{th J-S}) is a maximum of 130 °C/W. Proper thermal management is essential to keep the junction temperature below 120 °C. At elevated temperatures, the forward voltage decreases and luminous intensity drops. Designers must ensure adequate heat sinking, especially when operating at currents close to the maximum rating (70 mA).

3. Performance Curves

The typical optical and electrical characteristics are illustrated in the following figures (refer to the datasheet for graphical details):

• Forward Voltage vs. Forward Current (Fig. 1-7): The forward voltage increases nonlinearly with current, from about 2.20 V at 0 mA to 2.60 V at 150 mA (pulse condition). At the test current of 50 mA, V_F is typically 2.4 V.
• Relative Intensity vs. Forward Current (Fig. 1-8): The relative luminous intensity increases almost linearly with forward current up to 70 mA. At 70 mA, the intensity is approximately 80% higher than at 20 mA.
• Solder Temperature vs. Relative Intensity (Fig. 1-9): As the ambient or solder point temperature rises from 20 °C to 120 °C, the relative intensity decreases by about 15%. Thermal derating is required for high-temperature operation.
• Solder Temperature vs. Forward Current (Fig. 1-10): To prevent exceeding the maximum junction temperature, the forward current must be derated as the solder temperature increases. At 100 °C, the maximum allowed current is approximately 40 mA.
• Forward Voltage vs. Solder Temperature (Fig. 1-11): The forward voltage decreases linearly with temperature at a rate of roughly –2 mV/°C.
• Radiation Pattern (Fig. 1-12): The device exhibits a Lambertian-like radiation pattern with a wide 120° half-intensity angle, providing uniform illumination.
• Forward Current vs. Dominant Wavelength (Fig. 1-13): The dominant wavelength shifts slightly to longer wavelengths (red shift) as current increases. At 70 mA, the shift is about +2 nm compared to 10 mA.
• Spectral Distribution (Fig. 1-14): The emission spectrum peaks at approximately 621 nm with a full width at half maximum (FWHM) of about 20 nm. The color is saturated red.

4. Mechanical Package

4.1 Package Dimensions

The LED is packaged in a 3.50 mm × 2.80 mm × 1.85 mm PLCC-4 package. The top view shows a rectangular shape with a clear silicone lens on top. The cathode and anode are indicated on the bottom view by a chamfered corner (cathode) and a keying mark. All dimensions are in millimeters with a tolerance of ±0.2 mm unless otherwise noted.

4.2 Soldering Pattern (Recommended Land Pattern)

The recommended land pattern for PCB design is provided to ensure proper solder joint formation and heat dissipation. The pattern consists of two rectangular pads (2.40 mm × 1.60 mm) with a pitch of 4.60 mm between them. The total copper area should be maximized to improve thermal performance.

4.3 Polarity Identification

The cathode is indicated by a small notch or chamfer on the package body in the bottom view. The pin configuration is: Pin 1 (anode) and Pin 2 (cathode) on one side, and Pin 3 (anode) and Pin 4 (cathode) on the opposite side. Refer to the datasheet for exact orientation.

5. Assembly and Soldering

5.1 Reflow Soldering Profile

The LED is designed to withstand reflow soldering according to the following profile (based on JEDEC J-STD-020):

Reflow soldering must not be performed more than twice. If the interval between two soldering cycles exceeds 24 hours, the LEDs must be baked (60 °C, 24 h) to prevent moisture damage.

5.2 Hand Soldering

If hand soldering is required, use a soldering iron with a temperature below 300 °C and a dwell time under 3 seconds. Only one hand soldering operation is allowed.

5.3 Handling and Processing Precautions

• Do not apply excessive pressure on the silicone lens. Use proper pick-and-place nozzles designed for silicone encapsulated LEDs.
• Avoid mounting the LED on warped or non-coplanar PCB sections.
• After soldering, allow the board to cool gradually; do not force cool with air or liquid.
• Do not perform any bending or twisting of the PCB after soldering.
• Use only recommended cleaning solvents (isopropyl alcohol). Ultrasonic cleaning is not recommended as it may damage the LED.

6. Packaging and Storage

6.1 Packaging Specification

The LEDs are supplied in tape and reel packaging with the following details:

• Quantity: 2000 pieces per reel.
• Carrier tape: 8 mm width, pocket pitch 4.0 mm, with cover tape.
• Reel: 330 mm diameter, 100 mm hub diameter, 13 mm spindle hole.

6.2 Label Information

Each reel carries a label with part number, specification number, lot number, bin code (for VF, IV, wavelength), quantity, and date code.

6.3 Moisture Barrier Bag and Storage Conditions

LEDs are sealed in a moisture barrier bag (MBB) with desiccant. Storage conditions:

7. Reliability Testing

7.1 Test Items and Conditions

The LED has been subjected to the following reliability tests in accordance with the standards listed. Each test was performed on 20 samples with acceptance criteria of 0 failures (0/1).

7.2 Failure Criteria

A device is considered failed if it exceeds the following limits after the test:

• Forward voltage at 50 mA: > 1.1 × upper specification limit (U.S.L.)
• Reverse current at 5 V: > 2.0 × U.S.L.
• Luminous flux at 50 mA: < 0.7 × lower specification limit (L.S.L.)

8. Application Design Considerations

To achieve optimal performance and reliability, the following design guidelines should be followed:

• Current Limiting: A series resistor is mandatory to limit the forward current to no more than 70 mA. Even a small change in supply voltage can cause a large current variation due to the steep IV curve.
• Reverse Voltage Protection: The LED has a maximum reverse voltage of only 5 V. Ensure the circuit does not apply reverse bias during operation or switching transients.
• Thermal Management: At 50 mA, power dissipation is about 120 mW (typical V_F 2.4 V). With a thermal resistance of 130 °C/W, the junction temperature rise is 15.6 °C above the solder point. For high ambient temperatures, derate the current accordingly.
• ESD Protection: Although the LED can withstand 2000 V HBM, it is recommended to use ESD protection devices (e.g., zener diodes) in the circuit if the system is prone to electrostatic discharges.
• Chemical Compatibility: Avoid using materials that contain sulfur, bromine, chlorine, or volatile organic compounds (VOCs) that can outgas and attack the silicone encapsulation. The sulfur concentration in the environment should not exceed 100 ppm, and halogens (Br, Cl) individually below 900 ppm, total below 1500 ppm.
• Cleaning: If cleaning is necessary after soldering, use isopropyl alcohol. Do not use ultrasonic cleaning as it may cause wire bond damage.

9. Comparative Advantages

Compared to standard red LEDs of similar package size, this device offers several distinct advantages:

• Wide Viewing Angle: 120° (vs. typical 60°–90°) makes it ideal for uniform interior lighting.
• High Brightness: Up to 3500 mcd at 50 mA, enabling use in daylight-visible applications.
• Automotive Qualification: AEC-Q101 compliance ensures robustness under harsh automotive conditions (temperature extremes, vibration, high humidity).
• Low Thermal Resistance: 130 °C/W is competitive for a plastic package, allowing higher current operation with proper heat sinking.
• Narrow Wavelength Tolerance: Binning to 2.5 nm bins ensures color consistency for switch indicators.

10. Frequently Asked Questions (FAQ)

1. Q: What is the maximum continuous forward current? A: The absolute maximum is 70 mA. For reliable long-term operation, it is recommended to stay below 60 mA in high-temperature environments.
2. Q: Can I drive the LED without a resistor? A: No. A current-limiting resistor is essential to prevent thermal runaway. Even a constant voltage source is not recommended because V_F varies with temperature.
3. Q: How should I store unused LEDs? A: Keep them in the unopened moisture barrier bag at ≤30 °C and ≤75% RH. Once opened, use within 24 hours or bake before assembly.
4. Q: What is the difference between dominant wavelength and peak wavelength? A: Dominant wavelength is the human-perceived color (for red LEDs, it is typically close to the peak). The dominant wavelength is measured according to CIE standards; for this product, it ranges from 617.5 to 625 nm.
5. Q: Can I use this LED for outdoor automotive lighting? A: This device is specified for interior applications. For exterior use (e.g., taillights), additional environmental testing (UV, water ingress) may be required.
6. Q: Why is the silicone lens soft? A: Silicone is chosen for its excellent light transmission and high-temperature stability. However, it is softer than epoxy; avoid touching the lens with sharp objects.

11. Practical Application Cases

Case 1: Automotive Dome Light

A single LED can replace a traditional incandescent bulb in a dome light. With a 50 mA drive, the LED delivers ~2.9 cd, sufficient to illuminate a small car interior. A wide viewing angle ensures even light distribution. A resistor of 18 Ω (for a 12 V supply) limits current to ~50 mA, assuming a typical V_F of 2.4 V. The LED can be mounted on an aluminum-core PCB (MCPCB) for heat sinking.

Case 2: Switch Backlighting

For a push-button switch, the LED can be placed behind a translucent button. With a lower drive current (20 mA), the intensity (~1.5 cd) is adequate for ambient indication. This reduces power consumption and heat generation. The small PLCC-4 package fits well on standard FR4 PCBs.

12. Working Principle

The LED is a semiconductor light source based on the AlGaInP (aluminum gallium indium phosphide) material system. When a forward bias is applied across the p-n junction, electrons from the n-side recombine with holes from the p-side in the active region. This recombination releases energy in the form of photons (light) with a wavelength determined by the bandgap energy of the AlGaInP compound. By carefully controlling the composition, the emission is tuned to the red part of the spectrum (~621 nm). The PLCC-4 package uses a clear silicone lens to enhance light extraction and provide a wide radiation pattern.

13. Development Trends

The trend in automotive interior lighting is toward higher efficiency, smaller packages, and better color consistency. Future developments may include:

- Integration of multiple LEDs in a single package for RGB or tunable white solutions.

- Improved thermal resistance through advanced package designs (e.g., using metal leadframes or ceramic substrates).

- Higher brightness levels to support daylight-readable displays.

- Stricter binning tolerances as demanded by adaptive lighting systems.

- Increased use of LEDs in human-centric lighting (HCL) for ambiance control.

This product, with its AEC-Q101 qualification and wide-angle emission, is well positioned for the next generation of automotive interior illumination.