Ceramic 3535 Series 3W White LED Datasheet - Dimensions 3.5x3.5x?mm - Voltage 3.2V - Power 3W - English Technical Document

1. Product Overview

This document details the specifications for a high-power Ceramic 3535 series 3W white LED. This component is designed for applications requiring high luminous flux output and reliable performance in demanding thermal environments. The ceramic substrate offers excellent thermal conductivity, making it suitable for high-current operation and prolonged use.

1.1 Product Positioning and Core Advantages

The primary advantage of this LED series lies in its ceramic packaging. Compared to traditional plastic packages, ceramic provides superior heat dissipation, which directly translates to higher long-term reliability, stable color output, and extended operational lifetime, especially when driven at high currents like the typical 700mA specified. The 3535 footprint is a common industry standard, facilitating design-in and replacement.

1.2 Target Market and Applications

This LED is targeted at professional lighting applications where performance and longevity are critical. Typical use cases include:

• High-bay industrial lighting
• Commercial downlights and spotlights
• Outdoor area lighting
• Specialty horticultural lighting
• Any application requiring robust, high-output white light sources.

2. In-Depth Technical Parameter Analysis

All parameters are specified at a solder point temperature (Ts) of 25°C unless otherwise noted.

2.1 Absolute Maximum Ratings

These values represent the limits beyond which permanent damage to the device may occur. Operation under these conditions is not guaranteed.

• Forward Current (IF): 1000 mA (DC)
• Forward Pulse Current (IFP): 1400 mA (Pulse width ≤10ms, Duty cycle ≤1/10)
• Power Dissipation (PD): 3400 mW
• Operating Temperature (Topr): -40°C to +100°C
• Storage Temperature (Tstg): -40°C to +100°C
• Junction Temperature (Tj): 125°C
• Soldering Temperature (Tsld): Reflow soldering at 230°C or 260°C for 10 seconds maximum.

2.2 Electro-Optical Characteristics (Typical/Maximum)

• Forward Voltage (VF): 3.2V / 3.6V (at IF=700mA)
• Reverse Voltage (VR): 5V
• Reverse Current (IR): 50 µA (max)
• Viewing Angle (2θ1/2): 120° (typical)

3. Binning System Explanation

The LED is classified according to a multi-parameter binning system to ensure color and performance consistency.

3.1 Correlated Color Temperature (CCT) Binning

The product is available in standard CCTs ranging from 2700K (warm white) to 8000K (cool white). Each CCT is defined by a specific chromaticity region on the CIE diagram (e.g., 2700K corresponds to regions 8A, 8B, 8C, 8D). This ensures the emitted white light falls within a precise color space.

3.2 Luminous Flux Binning

Flux is binned by minimum output at 700mA. The bins are defined by a code (e.g., 2H, 2J, 2K) with associated minimum and typical luminous flux values in lumens. For example, a 70 CRI neutral white (3700-5000K) LED in bin 2L has a minimum flux of 172 lm and a typical flux of 182 lm. Note: Shipments guarantee the minimum flux and the CCT chromaticity region; actual flux may be higher.

3.3 Forward Voltage Binning

Forward voltage is also binned to aid in circuit design for current regulation.

• Code 2: VF = 2.8V to 3.0V
• Code 3: VF = 3.0V to 3.2V
• Code 4: VF = 3.2V to 3.4V

3.4 Model Numbering Rule

The product model follows a structured code: T □□ □□ □ □ □ – □□□ □□. The digits indicate, in order: product series, package code (e.g., '19' for Ceramic 3535), chip count code (e.g., 'P' for single high-power die), lens/optic code, luminous color code (e.g., 'L' for warm white, 'C' for neutral white, 'W' for cool white), internal code, luminous flux bin code, and forward voltage bin code.

4. Mechanical and Package Information

4.1 Outline Drawing and Dimensions

The LED uses a standard 3.5mm x 3.5mm ceramic package. Detailed dimensional drawings show the top view, side view, and critical measurements. Tolerances are specified as ±0.10mm for .X dimensions and ±0.05mm for .XX dimensions.

4.2 Recommended Pad Pattern and Stencil Design

A land pattern design is provided for PCB layout, ensuring proper soldering and thermal connection. A corresponding stencil design is also recommended to control solder paste volume during reflow assembly, which is crucial for achieving a reliable solder joint and optimal thermal path to the PCB.

5. Performance Curve Analysis

5.1 Forward Current vs. Forward Voltage (I-V Curve)

The I-V curve is essential for driver design. It shows the nonlinear relationship between current and voltage, with the typical forward voltage being 3.2V at 700mA. Designers must use a constant-current driver to ensure stable operation and prevent thermal runaway.

5.2 Forward Current vs. Relative Luminous Flux

This curve illustrates how light output increases with current. It typically shows a sub-linear relationship at higher currents due to efficiency droop and increased junction temperature. Operating at the recommended 700mA provides a balance between output and efficacy.

3.3 Spectral Power Distribution and Junction Temperature Effects

The relative spectral power distribution curve shows the intensity of light across wavelengths for a white LED, which is a combination of blue die emission and phosphor conversion. A separate curve shows how the spectrum may shift with increasing junction temperature, which can affect color point (chromaticity) and requires proper thermal management in the final design.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Parameters

The LED is compatible with standard lead-free reflow profiles. The maximum body temperature during soldering must not exceed 230°C for 10 seconds or 260°C for 10 seconds. It is critical to follow the recommended temperature profile to avoid damaging the internal die, wire bonds, or phosphor.

6.2 Handling and Storage Precautions

LEDs are sensitive to electrostatic discharge (ESD). Handle with appropriate ESD precautions. Store in a dry, controlled environment within the specified temperature range (-40°C to +100°C) to prevent moisture absorption, which can cause \"popcorning\" during reflow.

7. Packaging and Ordering Information

7.1 Tape and Reel Packaging

The product is supplied on embossed carrier tape wound on reels, suitable for automated pick-and-place assembly machines. Detailed dimensions of the carrier tape pockets and reel specifications are provided to ensure compatibility with manufacturing equipment.

7.2 Packing Specification

Specifications include the quantity per reel, reels per inner box, and boxes per shipping carton. Proper packaging ensures components are protected during transportation and storage.

8. Application Notes and Design Considerations

8.1 Thermal Management

This is the most critical aspect of designing with high-power LEDs. The ceramic package has low thermal resistance, but this advantage is lost without a proper thermal path. The PCB must have a thermally conductive design, often using metal-core PCBs (MCPCBs) or insulated metal substrates (IMS), with adequate heatsinking to maintain the junction temperature well below the maximum rating of 125°C for long life and stable performance.

8.2 Electrical Drive

Always use a constant-current LED driver. The voltage bin (Code 2, 3, or 4) should be considered when designing the driver's compliance voltage. Ensure the driver's current matches the intended operating point (e.g., 700mA) and has appropriate protections against over-current, over-voltage, and open/short circuits.

8.3 Optical Design

The LED has a wide 120-degree viewing angle. For directional lighting, secondary optics (lenses or reflectors) are required. The mechanical drawings provide the necessary dimensions for designing or selecting compatible optics.

9. Technical Comparison and Differentiation

The key differentiator of this ceramic 3535 LED compared to standard plastic 3535 packages is its thermal performance. The ceramic material typically offers a lower thermal resistance from the junction to the solder point, allowing it to handle higher drive currents or operate at a lower junction temperature for the same current, directly improving lifetime (L70, L90 metrics) and reducing color shift over time. This makes it preferable for high-reliability or high-stress applications.

10. Frequently Asked Questions (Based on Technical Parameters)

10.1 Can I drive this LED at 1000mA continuously?

While the absolute maximum rating is 1000mA, the typical operating condition is 700mA. Continuous operation at 1000mA would generate significantly more heat, pushing the junction temperature towards its limit and drastically reducing lifetime and potentially causing color shift. It is not recommended without exceptional thermal management and an understanding of the reduced reliability.

10.2 What is the meaning of the luminous flux \"minimum\" bin?

The minimum value is guaranteed; any LED shipped in that bin will meet or exceed that luminous output under standard test conditions. The typical value is the average output you can expect. The datasheet notes that shipped product may exceed the bin's minimum value but will always adhere to the specified CCT chromaticity region.

10.3 How do I interpret the CCT binning with codes like 5A, 5B, 5C, 5D?

These are specific quadrangles (or regions) on the CIE 1931 chromaticity diagram. An LED with a nominal CCT of 4000K will have its color coordinates fall within one of these four predefined regions (5A, 5B, 5C, or 5D). This system ensures tight color consistency within a batch and between batches ordered to the same specification.

11. Practical Design Case Study

Scenario: Designing a 50W high-bay light using multiple LEDs.
Design Steps:
1. Target Output: Determine total lumens required.
2. LED Selection: Choose a flux bin (e.g., 2M for ~190 lm typical at 700mA). Calculate number of LEDs: 50,000 lm target / 190 lm per LED ≈ 263 LEDs. In practice, optical and thermal losses must be factored in.
3. Thermal Design: For 263 LEDs at 3.2V, 0.7A each, total electrical power is ~589W. Assuming 40% wall-plug efficiency, ~353W is heat. A massive, actively cooled heatsink or distributed across multiple modules is necessary.
4. Electrical Design: Use multiple constant-current drivers, each powering a series-parallel string of LEDs, ensuring the total forward voltage of each string is within the driver's compliance range, considering the VF bin.
5. Optical Design: Use individual secondary lenses or a single large reflector to achieve the desired beam pattern and light distribution.

12. Operating Principle Introduction

A white LED operates on the principle of electroluminescence in a semiconductor and phosphor conversion. A direct-bandgap semiconductor chip (typically indium gallium nitride - InGaN) emits blue light when electrons recombine with holes across the bandgap under forward bias. This blue light then strikes a layer of phosphor material (typically yttrium aluminum garnet - YAG:Ce) deposited on or near the chip. The phosphor absorbs a portion of the blue photons and re-emits light across a broader spectrum in the yellow region. The combination of the remaining blue light and the broad yellow emission is perceived by the human eye as white light. The exact ratio of blue to yellow, and the specific phosphor composition, determines the Correlated Color Temperature (CCT) and Color Rendering Index (CRI) of the white light.

13. Technology Trends

The high-power LED market continues to evolve towards higher efficiency (more lumens per watt), improved reliability, and better color quality. Trends relevant to this ceramic 3535 package include:
Increased Efficacy: Ongoing improvements in internal quantum efficiency of the blue die and phosphor conversion efficiency.
Color Quality: Development of phosphor systems with higher CRI (Ra >90) and improved R9 (saturated red) values for better color rendering, especially in retail and museum lighting.
Thermal Management: Continued refinement of ceramic and other high-thermal-conductivity package materials (e.g., silicon-based, composite) to lower thermal resistance further, enabling higher power densities.
Miniaturization & Integration: While the 3535 footprint remains popular, there is a trend towards chip-scale packages (CSP) and integrated modules that combine multiple LED chips, drivers, and sometimes sensors into a single, easier-to-assemble unit, though these often sacrifice some of the thermal performance of a dedicated ceramic package like this one.