LED Red 3.0x3.0x0.55mm – Forward Voltage 2.3V – Power 1.09W – Dominant Wavelength 612.5-625nm – English Technical Datasheet

1. Product Overview

The RF-A4E31-R15H-S1 is a high‑performance red light emitting diode (LED) designed for demanding automotive interior and exterior lighting applications. It utilizes a state‑of‑the‑art AlGaInP (Aluminum Gallium Indium Phosphide) epitaxial structure grown on a substrate, delivering excellent brightness and reliability. The device is housed in a compact 3.0 mm × 3.0 mm × 0.55 mm EMC (Epoxy Molding Compound) package, which provides superior thermal management and robust mechanical strength.

This LED is qualified according to the AEC‑Q102 stress test qualification for automotive grade discrete semiconductors, making it suitable for harsh environments. It offers an extremely wide viewing angle of 120°, ensuring uniform light distribution. The product is RoHS compliant and has a moisture sensitivity level of 2 (MSL‑2). It is supplied on tape and reel (4000 pcs/reel) for efficient surface mount assembly.

2. Technical Parameters

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

The following table summarizes the key electrical and optical parameters measured under pulsed conditions at 25 °C:

• Forward Voltage (V_F): Min 2.0 V, Typ 2.3 V, Max 2.6 V at IF=350 mA (measurement tolerance ±0.1 V).
• Reverse Current (I_R): ≤10 µA at V_R=5 V.
• Luminous Flux (Φ): Min 55.3 lm, Max 93.2 lm at IF=350 mA (tolerance ±10%).
• Dominant Wavelength (λ_D): Min 612.5 nm, Max 625 nm at IF=350 mA.
• Viewing Angle (2θ_1/2): Typ 120°.
• Thermal Resistance (Junction to Solder): R_{th JS real} Typ 12 °C/W (Max 19 °C/W); R_th JS el Typ 6 °C/W (Max 10 °C/W) – measured at 350 mA, 25 °C.

At 25 °C, the photoelectric conversion efficiency η_e is 47% (pulse mode). The maximum power dissipation is 1092 mW, and the maximum forward current is 420 mA (700 mA peak with 1/10 duty cycle, 10 ms pulse width). The junction temperature must not exceed 150 °C.

2.2 Absolute Maximum Ratings

The device must be operated within the following limits:

• Power Dissipation (P_D): 1092 mW
• Forward Current (I_F): 420 mA
• Peak Forward Current (I_FP): 700 mA
• Reverse Voltage (V_R): 5 V
• ESD (HBM): 2000 V
• Operating Temperature (T_OPR): −40 to +125 °C
• Storage Temperature (T_STG): −40 to +125 °C
• Junction Temperature (T_J): 150 °C

3. Binning System

3.1 Forward Voltage and Luminous Flux Bins (IF=350 mA)

The LED is classified into bins based on forward voltage (V_F) and luminous flux (Φ):

• V_F bins (V): C0 (2.0–2.2), D0 (2.2–2.4), E0 (2.4–2.6).
• Luminous flux bins (lm): PA (55.3–61.2), PB (61.2–67.8), QA (67.8–75.3), QB (75.3–83.7), RA (83.7–93.2).
• Wavelength bins (nm): C2 (612.5–615), D1 (615–617.5), D2 (617.5–620), E1 (620–622.5), E2 (622.5–625).

Customers may specify required bin combinations to ensure consistent performance in their applications.

4. Performance Curves

The following typical optical characteristics are provided for design reference. All curves are measured at 25 °C unless otherwise noted.

4.1 Forward Voltage vs. Forward Current (Fig. 1‑6)

At low current, the forward voltage increases steeply from about 1.6 V at 0 mA to 2.0 V at 50 mA; above 100 mA the curve becomes nearly linear. The typical forward voltage at 350 mA is 2.3 V.

4.2 Forward Current vs. Relative Luminous Flux (Fig. 1‑7)

Relative luminous flux increases almost linearly with forward current up to 350 mA, reaching 100% relative flux at 350 mA. Beyond 350 mA, the slope gradually flattens due to thermal effects.

4.3 Junction Temperature vs. Relative Luminous Flux (Fig. 1‑8)

As junction temperature rises from −40 °C to 150 °C, the relative luminous flux decreases by about 40%. At 125 °C, the flux drops to approximately 70% of the 25 °C value.

4.4 Solder Temperature vs. Forward Current (Fig. 1‑9)

To avoid exceeding the maximum junction temperature, the forward current must be derated when the solder temperature exceeds 25 °C. At 125 °C solder temperature, the maximum allowed current is about 150 mA.

4.5 Voltage Shift vs. Junction Temperature (Fig. 1‑10)

The forward voltage shift (ΔV_F) is approximately linear with temperature: about −0.3 V at 150 °C and +0.3 V at −40 °C relative to 25 °C.

4.6 Radiation Diagram (Fig. 1‑11)

The LED emits light with a wide, Lambertian‑like distribution. The relative luminous intensity at ±60° is about 50% of the on‑axis intensity, corresponding to a full‑width at half‑maximum (FWHM) of 120°.

4.7 Dominant Wavelength Shift vs. Junction Temperature (Fig. 1‑12)

The dominant wavelength shifts to longer wavelengths as temperature increases. At 150 °C, the shift is approximately +8 nm relative to 25 °C; at −40 °C, the shift is about −7 nm.

4.8 Spectrum Distribution (Fig. 1‑13)

The peak emission wavelength is around 620 nm with a narrow full‑width at half‑maximum (FWHM) of approximately 20 nm. The spectrum shows negligible secondary peaks, ensuring pure red color.

5. Mechanical Package Information

5.1 Package Dimensions

The device is a 3.0 mm × 3.0 mm surface‑mount package with a total height of 0.55 mm. The top surface is optically clear silicone, while the bottom has a metal pad for thermal and electrical connection. Polarity is indicated by a notch on one corner (cathode).

5.2 Recommended Soldering Pad Pattern

To achieve good thermal and electrical performance, the recommended PCB land pattern is 2.4 mm × 2.3 mm for the anode pad and 1.5 mm × 0.65 mm for the cathode pad, with a gap of 0.55 mm. All dimensions are ±0.2 mm.

6. Assembly and Soldering Guidelines

6.1 Reflow Soldering Profile

The LED is compatible with standard SMT reflow soldering. A maximum of two reflow cycles is allowed. The recommended profile parameters are:

• Preheat: 150 °C → 200 °C, 60–120 s
• Time above 217 °C (T_L): max 60 s
• Peak temperature (T_P): 260 °C, hold time ≤10 s (within 5 °C of peak, max 30 s)
• Ramp‑up rate: ≤3 °C/s (from T_Smax to T_P)
• Cooling rate: ≤6 °C/s
• Total time from 25 °C to T_P: ≤8 min

If more than 24 h elapses between two reflows, the LEDs must be re‑baked to prevent moisture damage.

6.2 Handling and Cleaning

The silicone encapsulation is soft; avoid mechanical pressure on the lens. Use only isopropyl alcohol for cleaning. Ultrasonic cleaning is not recommended. Do not use adhesives that outgas organic vapors, as they can discolor the silicone.

7. Packaging and Ordering Information

The LEDs are packaged in antistatic moisture‑barrier bags. Each reel contains 4000 pieces. The carrier tape (8 mm wide) has dimensions: A₀ = 3.30 mm, B₀ = 3.50 mm, K₀ = 0.90 mm. The reel diameter is 180 mm. Labels include part number, lot number, bin code, quantity, and date. The storage conditions before opening the bag: ≤30 °C and ≤75% RH for up to 1 year. After opening, use within 24 h or bake at 60±5 °C for ≥24 h.

8. Application Notes

8.1 Typical Applications

This red LED is ideal for automotive interior lighting (instrument cluster, ambient lighting) and exterior lighting (tail lights, brake lights, turn signals). Its high brightness and wide viewing angle also suit general‑purpose indicator and signage applications where red color purity is critical.

8.2 Thermal Management

Because the LED’s light output and wavelength depend on junction temperature, proper heat sinking is essential. The thermal resistance of the PCB and any additional heatsink must be designed to keep T_J below 150 °C under worst‑case operating conditions. The solder pad should be connected to a large copper area.

8.3 Current Derating

When operating at elevated ambient temperatures, the forward current must be derated according to the solder‑temperature vs. forward‑current curve. For example, at T_s = 100 °C, the maximum allowed forward current is approximately 200 mA.

9. Technical Comparison

Compared to standard red LEDs based on AlGaAs or GaAsP, the AlGaInP technology used in this device offers higher luminous efficiency and better temperature stability. The wide 120° viewing angle is significantly broader than many competing 3.0 mm × 3.0 mm red LEDs that typically have 90°–100° half‑angle. The AEC‑Q102 qualification provides higher reliability for automotive use, with stricter stress tests than commercial‑grade equivalents.

10. Frequently Asked Questions

Q1: Can this LED be used at currents higher than 420 mA?
No. The absolute maximum rating for forward current is 420 mA (700 mA peak with duty cycle). Operating above this limit will cause permanent damage.

Q2: What is the typical lifespan of this LED?
While not directly specified in the datasheet, AEC‑Q102 qualified LEDs typically have very long lifetimes (>50,000 h) when operated within ratings and with proper thermal management.

Q3: How should I handle ESD sensitivity?
The device is rated for 2 kV HBM. Use standard ESD precautions: grounding wrist straps, conductive workstations, and antistatic packaging.

Q4: Can I mix different flux bins in the same application?
Mixing bins may cause visible brightness differences. It is recommended to use a single bin for uniform appearance unless the application tolerates variation.

11. Design Case Study

Automotive Rear Combination Lamp (RCL)
A customer designed a red LED module for a stop‑light using 6 pieces of RF‑A4E31‑R15H‑S1. The LEDs were arranged in 3 serial strings of 2 parallel (3S2P) to achieve 12 V compatibility. Each string was driven at 350 mA total (175 mA per LED) with a dedicated constant‑current driver. A copper‑core PCB (1.6 mm thick, 2 oz copper) was used to keep the solder temperature below 85 °C. The module passed thermal shock (−40 °C to 125 °C, 1000 cycles) and humidity tests (85 °C/85% RH, 1000 h) without failures.

12. Working Principle

The LED is based on a double‑heterostructure AlGaInP active layer grown on a transparent substrate (GaAs). When forward bias is applied, electrons and holes recombine radiatively in the active region, emitting photons with energy corresponding to the bandgap of the material (~2.0 eV, giving red light ~620 nm). The EMC package encapsulates the chip and provides a lens to extract light efficiently. Thermal dissipation occurs through the large bottom pad and the copper traces of the PCB.

13. Technology Trends and Outlook

AlGaInP technology continues to improve in efficiency and thermal stability. Future trends include higher‑flux bins via improved epitaxial growth and better chip design (e.g., patterned substrates). For automotive applications, the adoption of AEC‑Q102 qualification is becoming the norm, and this LED already meets that standard. Miniaturization (e.g., 2.0 mm × 2.0 mm packages) is an ongoing trend, but 3.0 mm × 3.0 mm remains popular for high‑power red LEDs because of its balance between power handling and light‑extraction area.