Ceramic 3535 Yellow LED Datasheet - Dimensions 3.5x3.5x?mm - Voltage 1.8-2.6V - Power 1.56W - English Technical Documentation

1. Product Overview

This document details the specifications for the T19 series, a high-performance yellow LED housed in a Ceramic 3535 package. This product is engineered for applications demanding high reliability, excellent thermal management, and consistent luminous output. The ceramic substrate provides superior heat dissipation compared to traditional plastic packages, making it suitable for high-current operation and challenging thermal environments.

Core Advantages: The key benefits of this LED series include a high luminous flux output and efficacy, low thermal resistance, and compatibility with Pb-free reflow soldering processes. It is designed to remain compliant with RoHS directives.

Target Market: Primarily targeted at automotive and signal lighting applications, including turn signals, signal lamps, rear lamps, and instrument panel illumination, where color consistency, longevity, and performance under varying temperatures are critical.

2. In-Depth Technical Parameter Analysis

2.1 Electrical and Optical Characteristics

All measurements are specified at an ambient temperature (Ta) of 25°C. The forward voltage (VF) ranges from a minimum of 1.8V to a maximum of 2.6V at a typical drive current of 350mA, with a measurement tolerance of ±0.1V. The luminous flux (ΦV) at this current ranges from 51 lm to 80 lm, with a tolerance of ±7%. The dominant wavelength (λ) for the yellow emission is between 585 nm and 595 nm (±2.0 nm tolerance). The device features a wide viewing angle (2θ1/2) of 120 degrees.

The absolute maximum ratings define the operational limits: a continuous forward current (IF) of 600 mA, a pulse forward current (IFP) of 1000 mA (under specific pulse conditions), and a maximum power dissipation (PD) of 1560 mW. The junction temperature (Tj) must not exceed 115°C.

2.2 Thermal Characteristics

Thermal management is a standout feature. The thermal resistance from the LED junction to the solder point (Rth j-sp) is specified as 5 °C/W at 350mA. This low value is a direct result of the ceramic package, which efficiently transfers heat away from the semiconductor junction, thereby enhancing reliability and maintaining light output stability. The operating temperature range is from -40°C to +105°C.

3. Binning System Explanation

To ensure color and performance consistency, the LEDs are sorted into bins based on key parameters.

3.1 Dominant Wavelength Binning

LEDs are categorized into two wavelength ranks: Y7 (585-590 nm) and Y8 (590-595 nm). This allows designers to select LEDs with precise color points for their application.

3.2 Luminous Flux Binning

The luminous output is binned into four ranks: AP (51-58 lm), AQ (58-65 lm), AR (65-72 lm), and AS (72-80 lm), all measured at IF=350mA. This binning facilitates designs requiring specific brightness levels.

3.3 Forward Voltage Binning

Forward voltage is classified into four ranks: C3 (1.8-2.0V), D3 (2.0-2.2V), E3 (2.2-2.4V), and F3 (2.4-2.6V). Knowledge of the voltage bin aids in driver circuit design and power supply selection.

4. Performance Curve Analysis

The datasheet includes several characteristic curves that are vital for design engineers.

Color Spectrum (Fig 1): Shows the spectral power distribution of the yellow LED, confirming the dominant wavelength and spectral purity.

Forward Current vs. Relative Intensity (Fig 3): Illustrates how the light output changes with increasing drive current. It is crucial for determining the optimal operating point for efficiency and longevity.

Forward Current vs. Forward Voltage (Fig 4): The IV curve is essential for designing the current-limiting circuitry. It shows the non-linear relationship between voltage and current.

Ambient Temperature vs. Relative Luminous Flux (Fig 5): Demonstrates the thermal derating of light output. As ambient temperature rises, luminous flux decreases. This curve is critical for applications subject to high temperatures.

Ambient Temperature vs. Wavelength (Fig 2) & Relative Forward Voltage (Fig 6): Show how the dominant wavelength and forward voltage shift with temperature, important for color-stable applications.

Ambient Temperature vs. Maximum Forward Current (Fig 8): A derating curve that specifies the maximum allowable forward current as a function of ambient temperature to prevent overheating and ensure reliability.

5. Mechanical and Package Information

5.1 Package Dimensions

The LED utilizes a Ceramic 3535 package. The dimensional drawing specifies the length and width as 3.5mm x 3.5mm. The drawing includes details for the overall height, lens geometry, and pad locations. All unspecified tolerances are ±0.2mm.

5.2 Recommended Solder Pad Layout

A footprint diagram is provided for PCB design, showing the recommended copper pad dimensions and spacing to ensure proper soldering, thermal transfer, and mechanical stability. Unspecified tolerances for the pad are ±0.1mm.

5.3 Polarity Identification

The cathode is typically marked on the device package. The pad layout also differentiates between the anode and cathode pads. Correct polarity connection is essential to prevent device damage.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Parameters

The LED is suitable for Pb-free reflow soldering. The profile specifies key parameters: a peak package body temperature (Tp) not exceeding 260°C, time above liquidous (217°C) between 60-150 seconds, and a maximum ramp-up rate of 3°C/second. The total time from 25°C to peak temperature should be 8 minutes maximum. It is recommended not to perform reflow soldering more than two times.

6.2 Handling and Storage Precautions

Devices are sensitive to electrostatic discharge (ESD), with a Human Body Model (HBM) rating of 2000V. Proper ESD handling procedures should be followed. Storage temperature should be between -40°C and +85°C.

7. Packaging and Ordering Information

7.1 Packaging Specifications

The LEDs are supplied on tape and reel for automated assembly. The tape width, pocket dimensions, and reel diameter are specified. Each reel contains a maximum of 1000 pieces. Reels are then packed in boxes, with capacities of 4/8 reels per small box or 48/64 reels per larger master box. A desiccant is included in the moisture-proof bag.

7.2 Part Numbering System

The part number (e.g., T19YE011A-xxxxxx) follows a structured code: T (series), 19 (Ceramic 3535 package), YE (Yellow), 0 (Color Rendering), 1 (Serial chips), 1 (Parallel chips), A (Component code), followed by internal and spare codes. This system allows precise identification of package type, color, and configuration.

8. Application Recommendations

8.1 Typical Application Scenarios

This LED is ideally suited for automotive exterior lighting such as turn signals and rear lamps, where its yellow color and reliability are key. It is also applicable for various signal lamps and backlighting instrument clusters.

8.2 Design Considerations

Thermal Design: Utilize the low thermal resistance by providing an adequate thermal path on the PCB, such as using thermal vias and connecting to a sufficient copper area or heatsink.

Current Driving: Use a constant current driver to ensure stable light output and prevent thermal runaway. Refer to the derating curve (Fig 8) when operating at high ambient temperatures.

Optical Design: The 120-degree viewing angle provides wide illumination. Secondary optics (lenses, reflectors) can be used to shape the beam pattern for specific applications.

9. Technical Comparison and Differentiation

Compared to standard plastic 3535 LEDs, the ceramic package offers significantly lower thermal resistance, leading to better performance at high currents and improved long-term reliability due to lower operating junction temperatures. The ceramic material also offers better resistance to moisture and harsh environmental conditions compared to plastic, making it more robust for automotive and outdoor applications.

10. Frequently Asked Questions (Based on Technical Parameters)

Q: What is the maximum current I can drive this LED at?
A: The absolute maximum continuous current is 600mA. However, for optimal lifetime and reliability, it is advised to operate at or below the test current of 350mA, especially in high-temperature environments, following the derating curve in Fig 8.

Q: How do I interpret the luminous flux binning?
A: The bin code (AP, AQ, AR, AS) indicates the guaranteed minimum and maximum flux output from the LED at 350mA. For consistent brightness in an array, specify LEDs from the same or adjacent flux bins.

Q: Can I use this LED for a turn signal that must meet specific color regulations?
A: Yes. The dominant wavelength bins (Y7: 585-590nm, Y8: 590-595nm) allow you to select LEDs that fall within the required yellow color specifications for automotive signals. Always verify against the applicable regulatory standard.

11. Practical Design and Usage Case

Case: Automotive Rear Turn Signal Lamp
A designer is creating a new LED-based rear turn signal cluster. They select this Ceramic 3535 Yellow LED for its proven reliability and color. They design a PCB with a 2oz copper layer and thermal vias under the LED pad to dissipate heat to a metal core or the lamp housing. They choose LEDs from the Y8 wavelength bin and AS flux bin for a bright, consistent amber color. A constant-current driver is designed to supply 300mA per LED (derated from 350mA for extra margin in the hot rear lamp environment). The wide 120-degree angle reduces the number of LEDs needed for the required field of view. The reflow profile is carefully controlled to the datasheet specifications to ensure solder joint integrity.

12. Operating Principle Introduction

This is a semiconductor light-emitting diode (LED). When a forward voltage is applied across the anode and cathode, electrons and holes recombine within the active region of the semiconductor chip, releasing energy in the form of photons (light). The specific materials used in the semiconductor layers determine the wavelength (color) of the emitted light. In this case, the materials are engineered to produce light in the yellow portion of the visible spectrum (585-595 nm). The ceramic package serves primarily as a robust mechanical housing and, critically, as an efficient thermal conductor to draw heat away from the semiconductor junction.

13. Technology Trends

The trend in high-power LEDs for automotive and industrial applications continues toward higher efficiency (more lumens per watt) and higher reliability. Ceramic packages are becoming more prevalent as they address thermal management challenges better than traditional plastics, enabling higher drive currents and power densities. There is also a focus on improving color consistency and stability over temperature and lifetime. Furthermore, miniaturization continues, with packages like 3535 offering high output in a relatively small footprint, enabling more compact and stylish lighting designs.