LED RF-A4E27-R22H-S4 Specification - 2.75x2.0x0.6mm Red - 1.8-2.4V - 1200mW - Automotive Grade English

1. Product Overview

The RF-A4E27-R22H-S4 is a high-performance red LED designed for automotive interior and exterior lighting applications. It utilizes AlGaInP (Aluminum Gallium Indium Phosphide) semiconductor technology to achieve efficient red light emission with a dominant wavelength ranging from 617.5nm to 627.5nm. The device is housed in a compact EMC (Epoxy Molding Compound) package measuring 2.75mm x 2.0mm x 0.6mm, enabling thin and lightweight designs. Key features include an extremely wide viewing angle (120 degrees), compatibility with standard SMT assembly processes, and compliance with AEC-Q102 stress test qualification for automotive grade discrete semiconductors. The LED is also RoHS compliant and has a moisture sensitivity level of 2 (MSL2), making it suitable for high-reliability applications.

1.1 Features

• EMC package for robust mechanical and thermal performance.
• Extremely wide viewing angle of 120° for uniform light distribution.
• Suitable for all SMT assembly and solder processes.
• Available on tape and reel (4000pcs/reel).
• Moisture sensitivity level: Level 2 (per JEDEC).
• RoHS compliant and meets AEC-Q102 qualification.

1.2 Applications

• Automotive interior lighting (e.g., dome lights, ambient lighting).
• Automotive exterior lighting (e.g., tail lights, brake lights, turn signals).
• Other general lighting where high reliability and wide viewing angle are required.

2. Technical Specifications

2.1 Electrical and Optical Characteristics (at Ts=25°C, IF=350mA)

The forward voltage is measured at 350mA with a tolerance of ±0.1V. The device is not designed for reverse operation. Luminous flux tolerance is ±10%. Dominant wavelength tolerance is ±0.005 (for chromaticity coordinates). All measurements are performed under Refond’s standardized testing environment.

2.2 Absolute Maximum Ratings

It is crucial to never exceed these limits. The forward current should be derated based on solder temperature to keep the junction temperature below 125°C. The device can withstand 8000V ESD (HBM) with a yield rate over 90%; however, proper ESD protection measures must be taken during handling.

2.3 Bin Ranges (at IF=350mA)

The product is shipped in specified bins for forward voltage, luminous flux, and dominant wavelength to ensure consistency within production lots.

• Forward Voltage Bins: B1 (1.8-1.9V), 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).
• Luminous Flux Bins: NA (37-40.9 lm), NB (40.9-45.3 lm), OA (45.3-50 lm), OB (50-55.3 lm).
• Dominant Wavelength Bins: D2 (617.5-620nm), E1 (620-622.5nm), E2 (622.5-625nm), F1 (625-627.5nm).

2.4 Typical Optical Characteristics Curves

The following curves provide insight into the LED’s performance under various conditions:

2.4.1 Forward Voltage vs. Forward Current

The forward voltage increases with current in a typical diode-like manner. At 350mA, VF is approximately 2.0-2.1V. The curve shows a linear rise from 1.8V to 2.4V over the current range.

2.4.2 Forward Current vs. Relative Intensity

Relative luminous intensity rises with forward current. At 350mA, the intensity is about 100%. Increasing current beyond 500mA is not recommended due to thermal constraints.

2.4.3 Solder Temperature vs. Relative Intensity

Higher solder temperature reduces light output. For example, at 105°C, relative intensity drops to approximately 60% of the value at 25°C.

2.4.4 Radiation Pattern

The LED has a wide lambertian-like radiation pattern with a half angle of 120°, providing uniform illumination across a broad area.

2.4.5 Spectrum Distribution

The peak emission is in the red region around 620-630nm, with a narrow spectral width typical of AlGaInP devices.

3. Mechanical Information

3.1 Package Dimensions

The LED package measures 2.75mm (length) × 2.00mm (width) × 0.60mm (height). The top view shows a light-emitting area of 1.57mm × 2.00mm. The bottom view reveals two cathode/anode pads with dimensions 0.48mm × 1.60mm and 0.54mm × 1.25mm, consistent with polarity markings. All dimensions have a tolerance of ±0.2mm unless otherwise noted.

3.2 Recommended Soldering Pattern

To ensure proper heat dissipation and mechanical strength, a specific PCB land pattern is recommended. The pattern includes two rectangular pads with a pitch of 1.70mm and additional thermal pads. Dimensions for the pads are 0.70mm × 1.10mm and 0.72mm × 0.55mm.

3.3 Polarity Identification

The anode and cathode are marked on the package. The bottom view shows a clear polarity indicator. Care must be taken to align the LED correctly during assembly.

4. Packaging Information

4.1 Packaging Specification

The LEDs are supplied in tape and reel packaging with 4000 pieces per reel. The carrier tape has a typical pitch of 4.0mm, and the reel diameter is 180mm with a hub diameter of 60mm. Each reel is sealed in a moisture barrier bag with a desiccant and a humidity indicator card.

4.2 Label Information

The label includes part number (RF-A4E27-R22H-S4), specification number, lot number, bin code, luminous flux bin, chromaticity bin, forward voltage bin, wavelength code, quantity, and date code.

4.3 Storage Conditions

Before opening the moisture barrier bag, LEDs should be stored at ≤30°C and ≤75% RH for up to 1 year from the date of manufacturing. After opening, the LEDs should be used within 24 hours under ≤30°C and ≤60% RH. If storage exceeds 24 hours, baking at 60±5°C for ≥24 hours is required before use.

5. Soldering Guidelines

5.1 Reflow Soldering Profile

Only two reflow cycles are allowed. The recommended profile includes: ramp-up rate ≤3°C/s, preheat 150-200°C for 60-120s, time above 217°C ≤60s, peak temperature 260°C with maximum duration of 10s, and cooling rate ≤6°C/s. Total time from 25°C to peak should not exceed 8 minutes.

5.2 Hand Soldering

If hand soldering is necessary, use a soldering iron with tip temperature ≤300°C for less than 3 seconds, and perform only once.

5.3 Cautions

• Do not apply mechanical stress on the silicone lens during or after soldering.
• Avoid warping the PCB before or after soldering.
• Do not use rapid cooling after reflow.
• Use appropriate pick-and-place nozzles to avoid damaging the soft silicone surface.

6. Application and Design Considerations

6.1 Thermal Management

Since the LED’s performance degrades with increasing junction temperature, adequate heat sinking is essential. The thermal resistance from junction to solder point is 20K/W. Designers should ensure that the solder temperature does not exceed the derating curve to keep Tj below 125°C.

6.2 ESD Protection

Although the LED can withstand 8000V HBM, ESD protection during handling and assembly is mandatory. Use grounded workstations, conductive mats, and wrist straps.

6.3 Chemical Compatibility

Avoid exposure to sulfur-containing compounds (≤100ppm), bromine (≤900ppm), chlorine (≤900ppm), and total halogens (≤1500ppm). VOCs from surrounding materials may cause silicone discoloration and light output loss. Isopropyl alcohol is recommended for cleaning if needed.

6.4 Circuit Design

Always include a current-limiting resistor to prevent excessive current. The forward voltage varies across bins; ensure the resistor value is chosen accordingly. The LED is not designed for reverse bias.

7. Reliability and Quality Assurance

7.1 Reliability Test Items

7.2 Failure Criteria

After testing, the LED is considered failed if the forward voltage exceeds 1.1 times the upper specification limit (U.S.L), reverse current exceeds 2.0 times U.S.L, or luminous flux drops below 0.7 times the lower specification limit (L.S.L). The values for U.S.L and L.S.L are defined per the product specification.

8. Principle and Technology Development

8.1 Working Principle

This red LED is based on AlGaInP heterostructures grown on a substrate. When forward biased, electrons and holes recombine in the active region, emitting photons in the red spectrum. The peak wavelength is determined by the composition of the semiconductor layers. The EMC package provides protection and efficient heat transfer.

8.2 Development Trends

Automotive lighting is evolving towards higher efficiency, smaller form factors, and greater reliability. LEDs like the RF-A4E27-R22H-S4 with AEC-Q102 qualification meet the stringent requirements of automotive environments. Future trends include further miniaturization, higher lumen output per watt, and improved thermal performance through advanced packaging technologies.