Ceramic 3535 LED T19 Series Datasheet - 3.5x3.5x1.6mm - Voltage 1.8-3.6V - Power up to 3.6W - English Technical Document

1. Product Overview

The T19 Series represents a high-performance, ceramic-based LED package designed for demanding lighting applications. The 3535 form factor (3.5mm x 3.5mm) provides a robust platform for efficient thermal management and high luminous output. This series is engineered to operate reliably under high current conditions, making it suitable for professional and industrial lighting solutions where longevity and consistent performance are critical.

2. Key Features and Applications

2.1 Core Features

• High Luminous Flux and Efficacy: Delivers superior light output per unit of electrical power, enhancing energy efficiency.
• High Current Operation: Specifically designed to handle elevated forward currents, supporting brighter illumination.
• Low Thermal Resistance: The ceramic substrate and package design facilitate excellent heat dissipation from the LED junction, which is crucial for maintaining performance and lifespan.
• Pb-free Reflow Soldering Compatible: Suitable for modern, environmentally friendly assembly processes.

2.2 Target Applications

• Outdoor and architectural lighting fixtures.
• Specialized horticulture lighting systems.
• Stage and entertainment lighting.
• Automotive signal lamps and rear lamps.

3. Part Numbering System

The part number follows the structure: T □□ □□ □ □ □ □ - □ □□ □□ □. Key elements include:

• Type Code (X1): '19' identifies this as the Ceramic 3535 package.
• CCT/Color Code (X2): Codes like BL (Blue), GR (Green), YE (Yellow), RE (Red), PA (PC Amber), CW (RGB), FW (RGBW).
• Serial/Parallel Chip Count (X4, X5): Indicates the internal configuration (1-Z).
• Color Code (X7): Specifies performance standards like ANSI (M), ERP (F), or high-temperature variants (R, T).

This system allows precise identification of the LED's electrical, optical, and thermal characteristics.

4. Absolute Maximum Ratings and Electrical/Optical Characteristics

4.1 Absolute Maximum Ratings (Ta=25°C)

These are stress limits that must not be exceeded, even momentarily, to prevent permanent damage.

• Forward Current (IF): Red: 700 mA; Green/Blue: 1000 mA.
• Pulse Forward Current (IFP): Red: 800 mA; Green/Blue: 1500 mA (Pulse Width ≤100μs, Duty ≤10%).
• Power Dissipation (PD): Red: 1820 mW; Green/Blue: 3600 mW.
• Reverse Voltage (VR): 5 V.
• Operating/Storage Temperature: -40°C to +105°C.
• Junction Temperature (Tj): Red: 105°C; Green/Blue: 125°C.
• Soldering Temperature: 230°C or 260°C peak for 10 seconds maximum during reflow.

4.2 Electrical & Optical Characteristics (Ta=25°C)

Typical performance under standard test conditions (IF=350mA).

• Forward Voltage (VF): Red: 1.8-2.6 V; Green/Blue: 2.8-3.6 V. (Tolerance: ±0.1V)
• Dominant Wavelength (λD): Red: 615-630 nm; Green: 520-535 nm; Blue: 450-460 nm. (Tolerance: ±2.0nm)
• Reverse Current (IR): Max 10 μA at VR=5V.
• Viewing Angle (2θ1/2): Typical 120 degrees.
• Thermal Resistance (Rth j-sp): Junction to solder point: Typical 5 °C/W.
• Electrostatic Discharge (ESD): Withstands 2000 V (Human Body Model).
• Luminous Flux: Varies by color and bin (see Section 5). (Tolerance: ±7%)

5. Binning Structure

To ensure color and brightness consistency, LEDs are sorted into bins.

5.1 Dominant Wavelength Bins (IF=350mA)

• Red: R6 (615-620nm), R1 (620-625nm), R2 (625-630nm).
• Green: GF (520-525nm), GG (525-530nm), G8 (530-535nm).
• Blue: B2 (450-455nm), B3 (455-460nm).

5.2 Luminous Flux Bins (IF=350mA)

• Red: AP (51-58 lm) to AT (80-88 lm).
• Green: AZ (112-120 lm) to BD (150-160 lm).
• Blue: AH (18-22 lm) to AL (30-37 lm).

5.3 Forward Voltage Bins (IF=350mA)

Codes from C3 (1.8-2.0V) to L3 (3.4-3.6V), allowing selection for specific driver requirements.

6. Performance Curve Analysis

The datasheet includes several key graphs (referenced as Fig 1-10) that illustrate performance under varying conditions. These are essential for design.

6.1 Spectral and Angular Characteristics

• Color Spectrum (Fig 1): Shows the spectral power distribution, critical for color-sensitive applications.
• Viewing Angle (Fig 7): Confirms the typical 120° Lambertian emission pattern.

6.2 Current, Voltage, and Temperature Dependencies

• Relative Intensity vs. Forward Current (Fig 3): Shows how light output scales with current, important for dimming and drive current selection.
• Forward Voltage vs. Forward Current (Fig 4): The IV curve is vital for thermal and electrical design of the driver circuit.
• Wavelength vs. Ambient Temperature (Fig 2): Indicates color shift with temperature, relevant for thermal management.
• Relative Luminous Flux vs. Ambient Temperature (Fig 5): Demonstrates light output reduction as temperature increases, highlighting the need for effective cooling.
• Relative Forward Voltage vs. Ambient Temperature (Fig 6): Shows the negative temperature coefficient of Vf.
• Maximum Forward Current vs. Ambient Temperature (Fig 8, 9, 10): These derating curves for Red, Green, and Blue LEDs are critical. They define the maximum safe operating current at any given ambient temperature to prevent exceeding the junction temperature limit.

7. Mechanical & Package Information

7.1 Package Dimensions

The ceramic 3535 package has a body size of 3.5mm x 3.5mm with a typical height of approximately 1.6mm. Dimensional drawings provide exact measurements for PCB footprint planning. Tolerances are typically ±0.2mm unless otherwise specified.

7.2 Polarity Identification

Important: Polarity differs by chip type.

• Green and Blue LEDs: Pad 1 is the Anode (+), Pad 2 is the Cathode (-).
• Red LEDs: Pad 2 is the Anode (+), Pad 1 is the Cathode (-).

Incorrect polarity connection will prevent the LED from illuminating.

7.3 Recommended Solder Pad Layout

A land pattern design is provided to ensure reliable soldering and optimal thermal transfer to the PCB. Adhering to this recommended layout minimizes soldering defects and maximizes heat sinking efficiency.

8. Soldering & Assembly Guidelines

8.1 Reflow Soldering Profile

The LED is compatible with standard Pb-free reflow processes. Key parameters from the profile include:

• Peak Package Body Temperature (Tp): Maximum 260°C.
• Time above Liquidous (TL=217°C): 60 to 150 seconds.
• Time within 5°C of Peak (Tp): Maximum 30 seconds.
• Ramp-up Rate (TL to Tp): Maximum 3°C/second.
• Ramp-down Rate (Tp to TL): Maximum 6°C/second.
• Total Cycle Time (25°C to Peak): Maximum 8 minutes.

Following this profile prevents thermal shock and ensures solder joint integrity.

9. Packaging and Handling

9.1 Tape and Reel Specifications

The LEDs are supplied on embossed carrier tape for automated pick-and-place assembly.

• Quantity per Reel: Maximum 1000 pieces.
• Cumulative Tolerance: ±0.25mm per 10 pitches.

The reel is labeled with part number, manufacturing data code, and quantity.

9.2 Storage and Handling

LEDs should be stored in their original, moisture-barrier packaging in a controlled environment (recommended: <30°C / 60% RH). Use standard ESD precautions during handling. After opening moisture-sensitive packaging, follow the floor life guidelines or bake according to standard IPC/JEDEC procedures before reflow if exceeded.

10. Application Notes and Design Considerations

10.1 Thermal Management

This is the single most critical factor for long-term reliability and performance. Despite the low thermal resistance (5°C/W typ.), a properly designed heatsink is mandatory, especially at high currents.

• Use a multilayer PCB with thermal vias under the LED pad connected to large copper planes.
• For high-power applications, consider an aluminum-core PCB (MCPCB) or an active cooling solution.
• Always refer to the Maximum Forward Current vs. Ambient Temperature derating curves (Fig 8-10) to select a safe operating current for your application's worst-case temperature.

10.2 Electrical Drive

• Drive the LED with a constant current source, not a constant voltage source, for stable light output and longevity.
• Account for the forward voltage bin and its tolerance when designing the driver's compliance voltage.
• Consider implementing soft-start or inrush current limiting in the driver circuit.
• For pulse operation (IFP), strictly adhere to the specified pulse width (≤100μs) and duty cycle (≤10%) limits.

10.3 Optical Design

• The 120° viewing angle is suitable for general illumination. For narrower beams, secondary optics (lenses) are required.
• Select appropriate wavelength and flux bins at the design stage to ensure color consistency and brightness uniformity across a multi-LED fixture.

11. Technical Comparison and Advantages

The ceramic 3535 package offers distinct advantages over traditional plastic SMD LEDs (like 2835 or 5050) in high-power scenarios:

• Superior Thermal Performance: Ceramic material has much higher thermal conductivity than plastic, leading to lower junction temperature at the same power level, which directly translates to longer lifespan and higher maintained light output (L70/L90).
• Higher Power Handling: Capable of sustaining higher drive currents (up to 1000mA/1500mA pulse) due to better heat dissipation.
• Enhanced Reliability: Ceramic is more resistant to thermal cycling stress and humidity, making it ideal for harsh environments like outdoor lighting.
• Stable Color Point: Better thermal stability minimizes color shift over time and operating conditions.

12. Frequently Asked Questions (FAQ)

Q: What is the main benefit of the ceramic package?
A: The primary benefit is excellent thermal management, allowing for higher drive currents, better reliability, and less performance degradation over time compared to plastic packages.

Q: Why are the polarity and maximum currents different for Red vs. Green/Blue LEDs?
A: This is due to the different semiconductor materials used (e.g., AlInGaP for Red, InGaN for Green/Blue), which have different electrical characteristics and efficiency.

Q: How do I choose the right forward current for my design?
A: Start with the typical test current (350mA). For higher brightness, increase the current but must consult the derating curves (Fig 8-10) based on your system's estimated maximum ambient temperature and thermal resistance to ensure Tj is not exceeded. Never exceed the Absolute Maximum Rating for continuous current.

Q: What does the 'Color Code' (e.g., M, F, R) in the part number mean?
A> It refers to the performance standard or temperature rating the LED is binned against. For example, 'M' is for standard ANSI bins, while 'R' and 'T' indicate bins rated for operation at higher junction temperatures (85°C and 105°C ANSI standards, respectively).

13. Design and Usage Case Study

Scenario: Designing a High-Power Outdoor Floodlight.

1. Requirement: High lumen output, robust for outdoor use, long lifespan (>50,000 hours L70).
2. LED Selection: The ceramic 3535 package is chosen for its thermal robustness. Green LEDs from the 'BD' flux bin (150-160 lm @350mA) are selected for high efficacy.
3. Thermal Design: An aluminum MCPCB with a 3mm thick base is used. Thermal simulation is run to ensure the LED junction temperature remains below 110°C at an ambient of 40°C.
4. Electrical Design: The driver is set to a constant current of 700mA. Referring to Fig 9, at 40°C ambient, the maximum allowed current is well above 700mA, providing a safe margin. The driver's output voltage range accommodates the Vf bin (e.g., H3: 2.8-3.0V).
5. Optical Design: A secondary optic (lens) is added to achieve the desired beam angle for flood lighting.
6. Result: A reliable, high-output fixture that maintains brightness and color over its lifetime due to effective thermal management enabled by the ceramic LED package.

14. Operating Principle

Light Emitting Diodes (LEDs) are semiconductor devices that emit light through electroluminescence. When a forward voltage is applied across the p-n junction, electrons and holes recombine in the active region, releasing energy in the form of photons. The wavelength (color) of the emitted light is determined by the bandgap energy of the semiconductor materials used (e.g., AlInGaP for red/orange, InGaN for blue/green). The ceramic package serves primarily as a mechanical support, electrical interconnect, and, most importantly, a highly efficient thermal path to conduct heat away from the semiconductor chip (die) to the printed circuit board and heatsink.

15. Technology Trends

The LED industry continues to evolve towards higher efficiency (more lumens per watt), higher power density, and improved reliability. Ceramic packages like the 3535 are part of this trend, enabling these advancements by solving thermal challenges. Future developments may include:

• Increased Efficacy: Ongoing improvements in epitaxial growth and chip design push the theoretical limits of light output.
• Advanced Packaging: Integration of multiple color chips (RGB, RGBW) within a single ceramic package for color-tunable fixtures, or chip-scale packaging (CSP) for even better thermal performance.
• Smart Integration: Incorporating control ICs or sensors directly into the LED package for intelligent lighting systems.
• Specialized Spectra: Further optimization of spectra for human-centric lighting (HCL) and horticulture (e.g., far-red, UV).

The fundamental drive is to provide more controllable, efficient, and durable light sources for an expanding range of applications.