LED Red 3.45x3.45x2.20mm - Forward Voltage 2.0V - Power 0.7W - Dominant Wavelength 620-630nm - English Technical Specification

1. Product Overview

The RF-AL-C3535L2K1RE-03 is a high-power red LED designed for demanding lighting applications. It utilizes an advanced ceramic substrate packaging technology (Chip on Substrate) which provides superior thermal management and mechanical reliability. The package dimensions are 3.45mm × 3.45mm × 2.20mm, making it suitable for compact lighting modules. This LED offers a typical luminous flux of 60-90 lm at 350mA, with a dominant wavelength between 620-630nm (deep red). The wide viewing angle of 120° ensures uniform light distribution. The product is RoHS compliant and rated for moisture sensitivity level 1 (MSL 1), allowing unlimited floor life before soldering.

2. Detailed Technical Parameter Analysis

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

• Forward Voltage (VF): 1.8V min, 2.0V typ, 2.4V max. This low forward voltage enables efficient driving from low-voltage power supplies. The tight binning (0.2V steps) allows consistent brightness in multi-LED arrays.
• Luminous Flux (Φv): 60 lm min, 75 lm typ, 90 lm max. The high luminous efficacy (≈215 lm/W at 350mA) is achieved through optimized chip design and ceramic packaging.
• Total Radiant Flux (Φe): 200 mW min, 350 mW typ, 500 mW max. Useful for applications requiring total optical power such as signaling.
• Dominant Wavelength (λD): 620 nm min, 625 nm typ, 630 nm max. This deep red matches well with phosphor-converted white LEDs for horticultural lighting or with traffic signal standards.
• Reverse Current (IR): maximum 10 µA at VR=5V, ensuring negligible leakage in reverse bias.
• Viewing Angle (2θ1/2): 120° typ, providing a wide beam for flood lighting applications.

2.2 Absolute Maximum Ratings

• Power Dissipation (PD): 1920 mW.
• Forward Current (IF): 800 mA continuous, 900 mA peak (1/10 duty, 0.1ms pulse).
• Reverse Voltage (VR): 5V.
• ESD Withstand (HBM): >2000V (typical yield >80%).
• Operating Temperature: -40°C to +85°C.
• Junction Temperature (TJ): maximum 125°C.

Thermal Design Consideration: The ceramic package provides excellent thermal conductivity. However, to keep junction temperature below 125°C, proper heatsinking is essential when operating near maximum current. For continuous 350mA operation, a copper pad area of at least 50mm² on a standard FR4 board is recommended.

3. Binning System Explanation

To facilitate consistent color and brightness matching, the LEDs are sorted into bins for forward voltage, luminous flux, and wavelength. The bin codes are printed on the reel label as shown in Table 1-3 of the datasheet.

When ordering or designing, ensure you specify the desired bin code or accept mixed bins based on application tolerance.

4. Performance Curves Interpretation

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

The curve shows a typical forward voltage of about 2.0V at 350mA, rising to approximately 2.4V at 800mA. The slope indicates a series resistance of about 0.8Ω. For applications requiring high current, voltage compensation in the driver is necessary.

4.2 Relative Luminous Intensity vs. Forward Current (Fig 1-7)

Relative intensity increases almost linearly with current up to 700mA, then begins to saturate slightly. At 350mA, relative intensity is 1.0 (reference). At 700mA, it is about 1.9, meaning doubling current yields <2x light output due to efficiency droop. Running above 500mA is less efficient.

4.3 Temperature vs. Relative Intensity (Fig 1-8)

At Ts=25°C, relative intensity is 1.0. As temperature rises to 85°C, intensity drops to about 0.85. This 15% decrease is typical for red AlInGaP LEDs. Thermal management is critical to maintain output in high ambient conditions.

4.4 Max Forward Current vs. Ts Temperature (Fig 1-9)

At Ts=25°C, maximum forward current is 800mA. At Ts=75°C, it derates to about 400mA. The curve ensures junction temperature stays below 125°C. For reliable operation, stay below the derating line.

4.5 Spectrum Distribution (Fig 1-10)

The emission spectrum is centered at 625nm with a FWHM of approximately 20nm. No secondary peaks are present, ensuring pure red color.

4.6 Radiation Pattern (Fig 1-11)

The radiation diagram shows a near-Lambertian distribution with 120° viewing angle. Relative intensity falls to 50% at ±60° off axis. This wide pattern is ideal for wash lighting and downlights.

5. Mechanical & Packaging Dimensions

5.1 Package Outline

• Top view: 3.45mm × 3.45mm square case.
• Side view: Height 2.20mm, with a lens protrusion of 0.85mm (total height from base).
• Bottom view: Two anode pads (large) and two cathode pads (small). Pad dimensions: 1.30mm × 0.65mm (anode), 1.30mm × 0.48mm (cathode).
• Polarity: The cathode side has a triangular mark or beveled corner (as per Fig 1-4).

5.2 Recommended Soldering Pad Pattern

The recommended PCB land pads are slightly larger than the component pads: 3.40mm × 1.30mm for anode, with 0.50mm pitch. Ensure proper solder mask defined pads to avoid bridging.

6. Soldering & Assembly Guidelines

6.1 Reflow Soldering Profile

The recommended lead-free reflow profile is in accordance with JESD22-B106. Key parameters:

• Preheat: 150°C – 200°C for 60-120 seconds.
• Peak temperature: 260°C max, time above 217°C: 60 seconds max.
• Cool down rate: 6°C/s maximum.
• Number of reflow cycles: maximum 2. If more than 24 hours between cycles, baking is required.

6.2 Hand Soldering

If manual soldering is necessary, use a soldering iron set below 300°C and complete within 3 seconds. Only one hand soldering operation is allowed.

6.3 Repair

Avoid repair after soldering. If unavoidable, use a double-head soldering iron to heat both pads simultaneously and remove the LED. Confirm no damage to adjacent components.

6.4 Storage & Baking

Before opening the aluminum bag: store at <30°C and <75% RH for up to 1 year. After opening: use within 168 hours at <30°C, <60% RH. If time exceeded, bake at 60°C, <5% RH for 24 hours.

7. Packaging & Ordering Information

• Standard package quantity: 1000 pieces per reel.
• Carrier tape: 8mm width, 4mm pitch, with 5.5mm sprocket holes. Cavity size 3.9×3.9mm.
• Reel dimensions: 178mm outer diameter, 14mm hub width.
• Label: Includes Part No., Spec No., Lot No., Bin Code (Φ, WD, VF), Quantity, and Date.
• Moisture barrier bag: Contains reel and desiccant, with ESD warning label.
• Cardboard box: Standard shipping carton with product labels.

8. Application Recommendations

8.1 Typical Applications

• Warning lights, downlights, wash wall lights, spot lights.
• Traffic signals and signaling lights.
• Landscape lighting, stage photography light, medical aesthetics equipment.
• Hotel, market, office, household indoor lighting.
• Article color lamps and strip lights.

8.2 Design Considerations

• Thermal management: Use adequate heat sinking. A thermal pad on PCB with thermal vias is recommended.
• ESD protection: Although the LED has >2000V HBM withstand, always use ESD-safe handling and consider a Zener diode across the LED if operating in high-ESD environments.
• Current regulation: Always drive with a constant current source. Small voltage variations cause large current changes (e.g., 0.1V shift can change current by ~125mA due to low dynamic resistance).
• Anti-sulfur/chlorine: Ensure surrounding materials have less than 100ppm sulfur, and bromine & chlorine each <900ppm (total <1500ppm) to prevent corrosion of silver-plated contacts.
• Lens cleaning: If needed, use isopropyl alcohol. Do not use ultrasonic cleaning.

9. Technical Comparison & Advantages

Compared to standard PPA (polyphthalamide) package LEDs, the ceramic package offers:

• Better thermal conductivity: Ceramic substrates have thermal conductivity >10 W/mK vs. <1 W/mK for plastic, reducing thermal resistance by 30-50%.
• Higher reliability at high temperatures: Ceramic withstands 125°C junction temperature without degradation, while plastic may discolor or delaminate.
• Lower moisture absorption: MSL 1 rating (unlimited floor life) vs. typical MSL 3 for plastic packages.
• Wider viewing angle: 120° vs. typical 110° for comparable plastic LED.

However, ceramic packages are typically more expensive. For cost-sensitive applications with lower power, plastic alternatives may be considered.

10. Frequently Asked Questions

Q: Can I drive this LED at 800mA continuously?
A: Yes, but only if junction temperature is kept below 125°C. Adequate heatsinking is mandatory. At 800mA, forward voltage is about 2.4V, power ~1.92W. A heatsink with thermal resistance <30 K/W is recommended for 85°C ambient.

Q: Why is the luminous flux bin range relatively wide (60-90lm)?
A: Standard production yields a distribution. Binning allows selecting tighter ranges. For single-LED applications, any bin works. For arrays, use same bin code for uniform brightness.

Q: What does the bin code "FB9" mean?
A: It indicates luminous flux between 60 and 65 lumens. Refer to Table 1-3 for all codes.

Q: Is this LED suitable for outdoor use?
A: Yes, with proper encapsulation in a luminaire that provides IP protection. The LED itself is not waterproof.

Q: Can I use reverse voltage in my circuit?
A: The absolute maximum reverse voltage is 5V. If there is a possibility of reverse bias (e.g., during startup or AC drive), add a blocking diode in series.

11. Practical Design Case Study

Case: Red Downlight Module (10W equivalent, 5 LEDs)
Design target: 300 lumens output at 350mA per LED. Five LEDs in series: total forward voltage ~10V (2.0V each). Driver: constant current 350mA, voltage compliance 12V. Thermal: 5 LEDs dissipate total ~3.5W. Mount on an aluminum PCB with 50mm×50mm heatsink. The 120° viewing angle allows use of a diffuser without dark spots. Using same bin (e.g., FBC for flux, C0 for voltage) ensures uniform brightness and no hot spots. Result: deep red accent lighting with excellent color consistency.

12. Operating Principle

This red LED is based on AlInGaP (Aluminum Indium Gallium Phosphide) semiconductor material grown on a GaAs substrate. When forward biased, electrons from the n-type layer recombine with holes in the p-type layer, emitting photons with energy corresponding to the bandgap of ~1.98 eV, producing 625nm red light. The ceramic substrate provides electrical insulation and a direct thermal path from the chip to the solder pads. The silicone lens encapsulates the chip and shapes the light output into a lambertian pattern.

13. Technology Trends

The industry is moving toward higher efficacy and smaller package sizes. Future developments for red LEDs include:

• Higher flux density: Improved chip designs (multi-junction, flip-chip) could double flux per package.
• Narrower wavelength bins: Future standards may require ±2nm tolerance for high-end displays.
• Integration with smart control: LEDs with integrated color sensors for self-calibration.
• Cost reduction of ceramic packages: As manufacturing scales, ceramic LEDs become competitive with plastic in mid-power ranges.

This product represents a balanced solution between performance and reliability for current solid-state lighting needs.

14. Reliability & Quality Assurance

The product has passed the following reliability tests (sample size 10pcs, 0 failures allowed):

• Reflow soldering (260°C, 2x)
• Thermal shock (-40°C to 100°C, 500 cycles)
• High temperature storage (100°C, 1000h)
• Low temperature storage (-40°C, 1000h)
• Life test (TA=25°C, 350mA, 1000h)
• HHHT (60°C/90%RH, 350mA, 1000h)

Criteria: Forward voltage shift <10%, luminous flux maintenance >80%, no open/short. This ensures product reliability in field applications.