LED 3535 White Specification - Size 3.45x3.45x2.20mm - Voltage 3.4V - Power 5.1W - English Technical Document

1. Product Overview

This LED is a high-power white light emitting diode based on a blue chip coated with phosphors. It is designed for general lighting and professional applications requiring high efficacy and reliability. The package is a compact 3.45mm x 3.45mm x 2.20mm ceramic SMD (Surface Mount Device) with a 120° wide viewing angle, suitable for various lighting fixtures. The product supports moisture sensitivity level 1, making it robust for standard SMT assembly processes. It is RoHS compliant and available in tape and reel packaging for automated pick-and-place.

2. Technical Parameter Deep Analysis

2.1 Electrical and Optical Characteristics

At a test current of 350mA and 25°C solder point temperature, the forward voltage (VF) ranges from 2.6V to 3.4V. Different part numbers correspond to different correlated color temperatures (CCTs) from 2200K to 6500K. The luminous flux at 350mA varies by CCT bin; for example, the 2700K variant (RF-AL-C3535L2K127-H6) produces 120-150lm at 350mA, while the 6000K variant (RF-AL-C3535L2K160-H6) produces 150-180lm at the same current. At 700mA, flux values roughly double, e.g., 250-310lm for the 2700K version. The color rendering index (Ra) is a minimum of 80 for all variants. Reverse current is limited to 10μA at 5V reverse voltage. The viewing angle (2θ½) is 120° typical.

2.2 Absolute Maximum Ratings

The LED can handle a maximum power dissipation of 5100mW, a forward current of 1500mA (DC) and a peak forward current of 1600mA (1/10 duty, 0.1ms pulse). The reverse voltage should not exceed 5V. Electrostatic discharge (HBM) withstand capability is 2000V. Operating and storage temperature range is -40°C to +85°C. The junction temperature (Tj) must be kept below 150°C. Thermal resistance from junction to solder point (RthJ-S) is typically 3.08°C/W at 700mA and 85°C ambient.

2.3 Binning System Explanation

The product is binned by forward voltage and luminous intensity at 350mA. Voltage bins are F0 (2.6-2.8V), G0 (2.8-3.0V), H0 (3.0-3.2V), and I0 (3.2-3.4V). Luminous intensity bins are FC4 (120-130lm), FC5 (130-140lm), FC6 (140-150lm), FC7 (150-160lm), FC8 (160-170lm), and FC9 (170-180lm). Each device is marked with a combined bin code. Chromaticity coordinates are provided in Table 1-4 for various CCT regions (e.g., 2700K, 3500K, 4000K) with specific CIE-x and CIE-y values.

3. Performance Curve Analysis

The specification includes typical optical characteristic curves (Fig.1-6 shows forward current vs. relative luminous intensity). As current increases, relative intensity rises non-linearly. The chromaticity coordinates diagram (Fig.1-7) illustrates how CCT varies within the phosphor conversion region. These curves are essential for understanding how the LED behaves under different drive conditions and for designing proper thermal management.

4. Mechanical and Package Information

4.1 Package Dimensions

The LED package has a top view dimension of 3.45mm x 3.45mm with a height of 2.20mm (including the lens). The bottom view shows two pads arranged for easy soldering. The anode pad (Pad 1) measures 1.30mm x 3.30mm, and the cathode pad (Pad 2) is 1.30mm x 3.30mm, both with 0.50mm clearance from the edge. The polarity is indicated by a small notch on the top view. Soldering patterns (Fig.1-5) recommend a pad layout of 3.50mm x 3.40mm with a central thermal pad of 1.30mm x 0.45mm. All dimensions have a tolerance of ±0.2mm unless specified.

4.2 Polarity and Soldering Pattern

The polarity is marked on the package: Pad 1 is the anode (positive), Pad 2 is the cathode (negative). The recommended soldering pattern includes a central thermal pad connected to the cathode for efficient heat dissipation. The pattern dimensions are 3.50mm x 3.40mm overall with the cathode pad extending to 0.65mm from the center. Proper alignment ensures good thermal and electrical contact.

5. Soldering and Assembly Guidelines

5.1 SMT Reflow Soldering Instructions

The document provides SMT reflow soldering instructions (section 3.1). Although the exact profile is not detailed, typical recommendations for ceramic package LEDs apply: preheat at 150-200°C for 60-120 seconds, ramp up to peak temperature of 245-260°C, and dwell above 217°C for 30-50 seconds. Cooling rate should not exceed 6°C/s. The LED is moisture sensitivity level 1, so no special baking is required if handled within the floor life. However, standard precautions such as using a nitrogen atmosphere and avoiding thermal shock are advised.

5.2 Handling Precautions

Handling precautions (section 4.1) include: avoid mechanical stress on the package, use proper ESD protection (the LED is rated to 2000V HBM but still requires ESD-safe handling), do not touch the lens with bare hands, store in a dry environment below 30°C and 60% RH, and follow the recommended soldering profile. The LED should not be operated beyond absolute maximum ratings to prevent degradation.

6. Packaging and Ordering Information

6.1 Packaging Specifications

The LEDs are supplied on tape and reel. The carrier tape has a width of 12mm (typical for 3535 packages) with pocket pitch of 4mm or 8mm depending on quantity. The reel diameter is 178mm (7 inches) or 330mm (13 inches) for higher quantities. Each reel carries a label with part number, bin code, quantity, and date code. The cardboard box packaging ensures safe transport. The product is available in both standard and custom binning combinations.

6.2 Reliability Test Items and Conditions

The document lists reliability test items (section 2.4) but does not provide detailed conditions in the excerpt. Typical tests for such LEDs include: room temperature operating life (1000 hours at rated current), high temperature storage (85°C/1000 hours), thermal shock, moisture resistance, solderability, and mechanical shock. The criteria for judging damage (section 2.5) typically involve permissible shifts in VF, flux, and color coordinates.

7. Application Recommendations

The LED is intended for a wide range of applications including:

• Warning lights, downlights, wall washers, spotlights, streetlights, visual lights, photographic fill lights.
• Plant lighting, landscape lighting, stage photography light.
• Hotels, markets, offices, household and other indoor uses.
• General purpose lighting where high CRI and efficiency are required.

Design considerations: adequate thermal management (e.g., using a metal-core PCB with low thermal resistance) is critical to keep the junction temperature below 150°C. The recommended operating current is 350mA to 700mA, but higher currents up to 1500mA are possible with proper heat sinking. The 120° viewing angle provides wide beam distribution, ideal for panel lights and retrofit bulbs.

8. Technical Comparison

Compared to plastic package LEDs, the ceramic package offers better thermal conductivity and higher reliability at elevated temperatures. It also provides superior color stability over life. The wide CCT range (2200K-6500K) makes it versatile for different lighting needs, from warm white for hospitality to cool white for commercial spaces. The typical Ra of 80 ensures decent color rendering, though higher CRI versions may be available upon request.

9. Frequently Asked Questions

Q1: Can I drive this LED at 1500mA?

A: Yes, but ensure the junction temperature does not exceed 150°C. Effective thermal management is required to avoid accelerated degradation.

Q2: What is the typical lifetime?

A: Based on LM-80 data for similar ceramic LEDs, the L70 lifetime at 350mA is typically >50,000 hours if operated within specifications.

Q3: How do I select the right bin code?

A: Binning by VF and flux allows you to choose the optimal balance between efficiency and brightness for your design. Consult the bin table in section 1.5.1.

Q4: Is this LED suitable for dimmable applications?

A: Yes, it can be dimmed by adjusting the forward current, but note that color shift may occur at very low currents.

10. Practical Case Studies

In a typical downlight application, using 12 LEDs (six in series, two strings in parallel) at 350mA per LED yields a total flux of ~1800 lumens and a power of ~12V*0.35A*2 = 8.4W per string? Actually careful calculation: each LED VF ~3.0V, so 6 in series = 18V, two strings = 36V total at 0.7A total? The power would be around 25W, suitable for a downlight with >2000 lumens. The ceramic package ensures low thermal resistance, allowing a simple heatsink.

11. Principle Introduction

The white LED works by electroluminescence from an InGaN blue chip, which emits blue light at around 450nm. This blue light excites yellow-emitting YAG:Ce phosphors coated on the chip; the combination of blue and yellow light produces white light. Different CCTs are achieved by varying the phosphor composition and thickness, changing the blue-to-yellow ratio.

12. Development Trends

The trend in high-power LEDs is towards higher efficacy (>200lm/W), higher CRI (>90), and smaller packages with improved thermal performance. Ceramic packaging allows for better heat dissipation compared to traditional plastic, enabling higher drive currents. Future developments may include multi-junction chips and integrated primary optics for more uniform beam patterns.