LED Yellow RF-A4E27-Y92E-Y4 Specification - 2.7x2.0x0.6mm - 2.0-2.6V - 520mW - Yellow 590nm

1. Product Overview

The RF-A4E27-Y92E-Y4 is a high-performance yellow light emitting diode (LED) manufactured using advanced AlGaInP (Aluminum Gallium Indium Phosphide) epitaxial technology on a substrate. This device is specifically designed for automotive interior and exterior lighting applications where reliability, wide viewing angle, and consistent color performance are critical. The LED is housed in a compact EMC (Epoxy Molding Compound) package with dimensions of 2.7mm x 2.0mm x 0.6mm, making it suitable for surface mount technology (SMT) assembly processes. Key features include an extremely wide viewing angle of 120 degrees, compliance with RoHS requirements, and qualification based on the AEC-Q102 stress test standard for automotive-grade discrete semiconductors. The moisture sensitivity level is rated Level 2, providing a balance between robustness and ease of handling during manufacturing.

2. Technical Parameter Deep Interpretation

2.1 Electro-Optical Characteristics (Ts=25°C)

At a test current of 150mA, the forward voltage (VF) ranges from a minimum of 2.0V to a maximum of 2.6V, with typical performance around 2.2-2.4V depending on the bin. The reverse current (IR) at VR=5V is extremely low, typically below 10µA, ensuring stable operation in reverse bias conditions. The luminous flux (Φ) spans from 19.6lm to 26.9lm, categorized into three bins: KA (19.6-21.8lm), KB (21.8-24.2lm), and LA (24.2-26.9lm). This allows customers to select tight flux bins for uniform lighting designs. The dominant wavelength (λD) is tightly controlled between 587.5nm and 595nm, with three sub-bins: D2 (587.5-590nm), E1 (590-592.5nm), and E2 (592.5-595nm). This ensures excellent color consistency across batches. The viewing angle (2θ1/2) is typically 120 degrees, providing broad illumination coverage ideal for automotive indicators and backlighting.

2.2 Absolute Maximum Ratings

The device can withstand a maximum power dissipation (PD) of 520mW, with a forward current (IF) up to 200mA continuous and a peak forward current (IFP) of 350mA (1/10 duty cycle, 10ms pulse). The reverse voltage (VR) limit is 5V. Electrostatic discharge (ESD) protection meets HBM 2000V, ensuring robustness in assembly environments. The operating temperature range extends from -40°C to +125°C, storage temperature from -40°C to +125°C, and the maximum junction temperature (TJ) is 150°C. Thermal resistance Rth JS (real) is typically 35°C/W and maximum 46°C/W; Rth JS (electrical) is typically 28°C/W and maximum 37°C/W. Proper thermal management is essential to keep the junction temperature below the maximum rating.

2.3 Binning System

The LED is sorted into bins for forward voltage, luminous flux, and dominant wavelength at IF=150mA. Forward voltage bins: C0 (2.0-2.2V), D0 (2.2-2.4V), E0 (2.4-2.6V). Luminous flux bins: KA (19.6-21.8lm), KB (21.8-24.2lm), LA (24.2-26.9lm). Dominant wavelength bins: D2 (587.5-590nm), E1 (590-592.5nm), E2 (592.5-595nm). This binning system allows designers to select LEDs with tightly matched electrical and optical characteristics, reducing variability in final products.

3. Performance Curve Analysis

3.1 Forward Voltage vs. Forward Current

The current-voltage (I-V) characteristic curve shows a typical exponential behavior with a turn-on voltage around 1.8V. At 150mA, the forward voltage is approximately 2.2V. The curve provides essential data for designing constant current drivers.

3.2 Relative Luminous Flux vs. Forward Current

The relative flux increases linearly with forward current up to about 150mA, then starts to saturate due to junction heating. At 150mA, the relative flux is normalized to 100%. This relationship helps in optimizing drive current for desired brightness without exceeding power limits.

3.3 Temperature Dependence

The luminous flux decreases as junction temperature rises: at Tj=125°C, the relative flux drops to approximately 80% of the value at 25°C. Similarly, forward voltage decreases with increasing temperature (negative temperature coefficient). The dominant wavelength shifts to longer wavelengths (red shift) with temperature rise, approximately 0.05-0.1nm/°C. These thermal effects must be accounted for in high-temperature applications like automotive interiors.

3.4 Radiation Pattern

The radiation diagram shows a broad Lambertian distribution with a half-intensity angle of about 60° (120° total viewing angle). The intensity is uniform across the emission cone, making this LED suitable for applications requiring wide-angle illumination.

3.5 Spectrum Distribution

The spectral emission peaks around 590-592nm with a full width at half maximum (FWHM) of approximately 15-20nm. The spectrum shows minimal parasitic emission outside the yellow band, ensuring high color purity.

4. Mechanical and Packaging Information

4.1 Package Dimensions

The LED package has a top view dimension of 2.70mm x 2.00mm, with a height of 0.60mm (all tolerances ±0.2mm unless otherwise noted). The bottom view shows two anode pads (A) and two cathode pads (C), clearly indicated. The recommended soldering land pattern dimensions are provided for reliable solder joint formation. The polarity marking is clearly indicated on the package.

4.2 Polarity and Soldering Patterns

The pinout identifies pads: Anode (A) pads are 1.30mm x 0.45mm, Cathode (C) pads are 1.30mm x 1.20mm. The solder pad layout on PCB should match the recommended footprint to ensure good thermal and electrical contact.

5. Soldering and Assembly Guidelines

5.1 Reflow Soldering Profile

The recommended reflow profile follows JEDEC standards: preheat from 150°C to 200°C for 60-120 seconds, ramp-up rate ≤3°C/s, time above 217°C (TL) up to 60 seconds, peak temperature (TP) 260°C with a time within 5°C of peak (tp) up to 10 seconds, cooling rate ≤6°C/s. The total time from 25°C to peak should not exceed 8 minutes. No more than two reflow cycles are allowed, and if the interval between cycles exceeds 24 hours, the LEDs must be baked to remove moisture.

5.2 Handling Precautions

The encapsulant is silicone, which is softer than traditional epoxy. Avoid mechanical pressure on the lens surface. Use appropriate nozzle force during pick-and-place. Do not mount LEDs on warped PCB or bend the board after soldering. Avoid rapid cooling after reflow. For cleaning, isopropyl alcohol is recommended; ultrasonic cleaning may cause damage. The storage conditions before opening the aluminum bag: ≤30°C, ≤75% RH, for up to 1 year. After opening, use within 24 hours at ≤30°C, ≤60% RH. If exceeded, bake at 60±5°C for >24 hours.

6. Packaging and Ordering Information

6.1 Packaging Specification

The LEDs are supplied on tape and reel with 4000 pieces per reel. The carrier tape dimensions: A0=2.10±0.1mm, B0=3.05±0.1mm, K0=0.75±0.1mm (depth). The tape width is 8.0±0.2mm. Reel dimensions: diameter 180±1mm, width 12±0.1mm, hub diameter 60±1mm. Each reel is labeled with part number, spec number, lot number, bin code (luminous flux, chromaticity bin, forward voltage, wavelength), quantity, and date. The reel is sealed in a moisture barrier bag with desiccant and humidity indicator card, then packed in a cardboard box.

7. Application Recommendations

This yellow LED is ideally suited for automotive lighting applications including interior ambient lighting, dashboard indicators, turn signals, and exterior side markers. The wide viewing angle ensures good visibility from various angles. The AEC-Q102 qualification guarantees reliability under harsh automotive conditions (temperature cycling, humidity, vibration). For optimal performance, use constant current driving with appropriate current-limiting resistors. Thermal design is critical: ensure the PCB provides adequate heat sinking to keep the junction temperature below 150°C. The maximum continuous forward current of 200mA should be derated at high ambient temperatures as shown in the solder temperature vs. forward current curve. Avoid exposure to sulfur-containing compounds (>100ppm) and halogens (bromine <900ppm, chlorine <900ppm, total <1500ppm) to prevent corrosion and light output degradation.

8. Technology Comparison

Compared to traditional yellow LEDs based on GaAsP or InGaAlP older technologies, the AlGaInP LED used in this part offers higher luminous efficacy, better temperature stability, and narrower wavelength tolerance. The EMC package provides better moisture resistance than conventional epoxy packages and enables higher reliability in automotive environments. The 120° viewing angle is wider than many standard SMD LEDs (typically 110°), making it more suitable for edge-lit or backlight applications. The AEC-Q102 qualification sets this part apart from many commercial-grade LEDs, ensuring long-term performance under extreme conditions.

9. Frequently Asked Questions

Q1: Can I use this LED at a higher current than 150mA?
A: The absolute maximum continuous forward current is 200mA. However, operating at higher current increases junction temperature and may reduce lifetime or cause color shift. Always verify thermal conditions at the intended operating point.

Q2: What is the typical lifespan of this LED?
A: When operated within absolute maximum ratings and with proper thermal management, the LED is expected to exceed 50,000 hours of operation. The AEC-Q102 qualification includes long-term life tests (1000 hours at 105°C/150mA).

Q3: How should I clean the LED after soldering?
A: Use isopropyl alcohol (IPA) for cleaning. Avoid solvents that may attack silicone or EMC material. Do not use ultrasonic cleaning as it can damage wire bonds.

Q4: What is the storage condition after opening the moisture barrier bag?
A: Store at ≤30°C and ≤60% RH. Use within 24 hours. If not used, bake at 60±5°C for >24 hours before use.

10. Practical Application Cases

In an automotive instrument cluster, this yellow LED can be used for warning indicators (e.g., check engine, high beam). Due to its 120° viewing angle, the indicator is visible even at off-axis positions. In exterior tail lights, multiple LEDs can be used in series-parallel arrays to achieve required brightness with redundancy. A typical design uses 6 LEDs in series driven by a constant current source of 150mA, with a total forward voltage around 13.2V. Thermal vias under the LED pads help dissipate heat to the PCB copper plane. The LED's narrow wavelength bin ensures uniform amber color across the light fixture, meeting automotive ECE regulations for signal lights.

11. Principle Introduction

The LED's light emission originates from the recombination of electrons and holes in the active layer of the AlGaInP heterostructure. The bandgap energy of the active material determines the dominant wavelength. By adjusting the composition of aluminum, gallium, indium, and phosphorus, the emission can be tuned across the yellow to red spectrum. In this device, the composition is optimized for 590nm yellow emission. The structure is grown on a substrate to allow epitaxial layers with high crystalline quality. The EMC package encapsulates the chip with a phosphor-free silicone lens that provides high extraction efficiency and wide radiation pattern.

12. Development Trends

The automotive lighting industry is moving toward miniaturization, higher efficiency, and tighter color control. LEDs with smaller footprints (like 2.7x2.0mm) enable thinner light guides and more compact designs. Future trends include integration of advanced thermal management (e.g., ceramic substrates), increased flux per package, and smart LED modules with integrated drivers. The push toward autonomous vehicles will demand even higher reliability and redundancy in lighting systems. This LED, with its AEC-Q102 qualification, is well-positioned to meet these evolving requirements.