Ceramic 3535 Series 1W Yellow LED Datasheet - Dimensions 3.5x3.5x?mm - Voltage 2.2V - Power 1W - English Technical Document

1. Product Overview

The Ceramic 3535 series is a high-power, surface-mount LED designed for applications requiring robust performance and reliable thermal management. The ceramic substrate offers excellent heat dissipation, making it suitable for high-current operation and demanding environments. This specific model, T1901PYA, is a 1W Yellow LED, characterized by its high luminous flux output and stable performance across a wide temperature range.

The core advantages of this series include superior thermal conductivity compared to standard plastic packages, leading to longer lifespan and maintained luminous output. The target markets include automotive lighting (interior and signal lighting), industrial lighting, high-bay lighting, and specialty illumination where color consistency and reliability are paramount.

2. Technical Parameters Deep Dive

2.1 Absolute Maximum Ratings (T_s=25°C)

The following parameters define the operational limits beyond which permanent damage to the device may occur. These are not conditions for continuous operation.

• Forward Current (I_F): 500 mA (DC)
• Forward Pulse Current (I_FP): 700 mA (Pulse Width ≤10ms, Duty Cycle ≤1/10)
• Power Dissipation (P_D): 1300 mW
• Operating Temperature (T_opr): -40°C to +100°C
• Storage Temperature (T_stg): -40°C to +100°C
• Junction Temperature (T_j): 125°C
• Soldering Temperature (T_sld): Reflow soldering at 230°C or 260°C for a maximum of 10 seconds.

2.2 Electro-Optical Characteristics (T_s=25°C, I_F=350mA)

These are the typical performance parameters under standard test conditions.

• Forward Voltage (V_F): Typical 2.2V, Maximum 2.6V
• Reverse Voltage (V_R): 5V
• Peak Wavelength (λ_d): 625 nm
• Reverse Current (I_R): Maximum 50 µA (at V_R=5V)
• Viewing Angle (2θ_1/2): 120°

2.3 Thermal Characteristics

The ceramic package provides a low thermal resistance path from the LED chip (junction) to the solder pads and subsequently to the printed circuit board (PCB). Effective thermal management on the application board is critical to maintain performance and longevity. Operating at or near the maximum junction temperature will accelerate lumen depreciation and can lead to premature failure. Designers must ensure adequate heat sinking, especially when driving the LED at its maximum rated current.

3. Binning System Explanation

To ensure color and brightness consistency in production, LEDs are sorted (binned) according to key parameters. This allows designers to select parts that meet specific application requirements.

3.1 Luminous Flux Binning (at 350mA)

Luminous flux is measured in lumens (lm). The bins define minimum and typical values.

• Code 1L: Min 30 lm, Typ 35 lm
• Code 1M: Min 35 lm, Typ 40 lm
• Code 1N: Min 40 lm, Typ 45 lm
• Code 1P: Min 45 lm, Typ 50 lm
• Code 1Q: Min 50 lm, Typ 55 lm

Note: Luminous flux tolerance is ±7%.

3.2 Forward Voltage Binning (at 350mA)

Forward voltage bins help in designing consistent current drive circuits, especially in multi-LED arrays.

• Code C: 1.8V to 2.0V
• Code D: 2.0V to 2.2V
• Code E: 2.2V to 2.4V
• Code F: 2.4V to 2.6V

Note: Forward voltage tolerance is ±0.08V.

3.3 Dominant Wavelength Binning

This defines the shade of yellow light emitted, ensuring color uniformity.

• Code Y1: 585 nm to 588 nm
• Code Y2: 588 nm to 591 nm
• Code Y3: 591 nm to 594 nm

4. Performance Curve Analysis

The following graphs illustrate the relationship between key parameters, which is crucial for circuit design and thermal management.

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

This curve shows the exponential relationship between current and voltage. The forward voltage increases with current and is also temperature-dependent. Designers use this to select appropriate current-limiting resistors or constant-current driver settings. Operating at the typical 350mA yields a V_F around 2.2V.

4.2 Forward Current vs. Relative Luminous Flux

This graph demonstrates that light output increases with current but not linearly. At higher currents, efficiency drops due to increased heat generation (droop effect). The 350mA operating point is chosen as a balance between high output and good efficacy. Driving beyond this point requires meticulous thermal design.

4.3 Junction Temperature vs. Relative Spectral Power

As the junction temperature rises, the spectral output of the LED can shift slightly. For yellow LEDs, this may manifest as a minor change in dominant wavelength or color purity. Maintaining a low junction temperature is key to stable color performance over the product's lifetime.

4.4 Spectral Power Distribution

The band energy characteristic curve shows the emission spectrum of the yellow LED, centered around 625 nm. It has a relatively narrow spectral width, typical for monochromatic LEDs, which is ideal for applications requiring saturated color.

5. Mechanical & Packaging Information

5.1 Outline Dimensions

The package follows the standard 3535 footprint: approximately 3.5mm x 3.5mm in base dimensions. The exact height is not specified in the provided excerpt. Detailed mechanical drawings with tolerances (e.g., .X: ±0.10mm, .XX: ±0.05mm) are included in the full datasheet for PCB layout.

5.2 Recommended Pad Layout & Stencil Design

The datasheet provides suggested land pattern (footprint) and solder stencil designs to ensure reliable soldering. The pad design is critical for both electrical connection and heat transfer. The thermal pad underneath the component must be properly soldered to a corresponding copper pad on the PCB to facilitate heat dissipation. The stencil aperture design controls the volume of solder paste deposited.

5.3 Polarity Identification

The LED has an anode and cathode. Polarity is typically marked on the device itself (e.g., a notch, dot, or trimmed corner) and must be correctly oriented on the PCB according to the footprint diagram. Reverse connection will prevent the LED from illuminating and applying reverse voltage beyond the rated 5V can damage it.

6. Soldering & Assembly Guidelines

6.1 Reflow Soldering Profile

The LED is compatible with standard infrared or convection reflow soldering processes. Two profiles are specified:
1. Peak temperature of 230°C.
2. Peak temperature of 260°C.
In both cases, the time above liquidus (typically ~217°C for SAC alloys) must be controlled, and the time at peak temperature must not exceed 10 seconds to prevent thermal damage to the LED chip and package.

6.2 Handling & Storage Precautions

• ESD Sensitivity: Although not explicitly stated as a sensitive device, standard ESD precautions during handling are recommended.
• Moisture Sensitivity: The ceramic package is generally less susceptible to moisture absorption than plastic packages, but storage in a dry environment is advised.
• Cleaning: If cleaning is required after soldering, use compatible solvents that do not damage the LED lens or packaging material.

6.3 Storage Conditions

Store in the original moisture-barrier bag at temperatures between -40°C and +100°C, in a low-humidity environment. Avoid exposure to direct sunlight or corrosive gases.

7. Packaging & Ordering Information

7.1 Carrier Tape Specifications

The LEDs are supplied on embossed carrier tape for automated pick-and-place assembly. The tape width, pocket dimensions, and pitch are designed to be compatible with standard SMT equipment. The provided diagram shows the detailed dimensions of the carrier tape for the 3535 ceramic series.

7.2 Reel Packaging

The carrier tape is wound onto standard reels. The reel quantity (e.g., 1000 pieces, 4000 pieces) is typically specified by the manufacturer. The reel is labeled with part number, quantity, lot number, and binning codes.

7.3 Part Numbering System

The model number T1901PYA follows a structured coding system:
• T: Manufacturer series prefix.
• 19: Package code for Ceramic 3535.
• P: Die count code for a single high-power die.
• Y: Color code for Yellow.
• A: Internal code or specific variant.
Additional suffixes may indicate flux bin (e.g., 1M), voltage bin (e.g., D), and wavelength bin (e.g., Y2).

8. Application Suggestions

8.1 Typical Application Scenarios

• Automotive Lighting: Daytime running lights (DRLs), turn signals, interior ambient lighting.
• Industrial & Commercial Lighting: High-bay lights, task lighting, machine vision illumination.
• Signage & Decoration: Channel letters, architectural accent lighting, decorative light strips.
• Specialty Lighting: Medical devices, agricultural lighting (specific spectra).

8.2 Design Considerations

• Driver Selection: Use a constant current driver for stable light output and longevity. The drive current should be set based on the required brightness and thermal design margin.
• Thermal Management: This is the most critical aspect. Use a PCB with sufficient copper thickness (e.g., 2oz) for the thermal pad. Consider using thermal vias to transfer heat to inner layers or a backside heatsink. The maximum junction temperature (125°C) should not be exceeded.
• Optics: The 120° viewing angle provides wide illumination. For focused beams, secondary optics (lenses or reflectors) designed for the 3535 footprint can be used.
• Series/Parallel Arrays: When connecting multiple LEDs, match them by forward voltage bin to ensure even current distribution, especially in parallel strings. Constant current drivers are preferred for series strings.

9. Technical Comparison & Differentiation

Compared to standard plastic 3535 LEDs, the ceramic version offers:
• Superior Thermal Performance: Ceramic substrates have much higher thermal conductivity than plastic, leading to lower junction temperature at the same drive current, which translates to higher light output, better color stability, and longer lifespan.
• Higher Reliability: Ceramic is resistant to yellowing under UV exposure and is more robust in high-temperature and high-humidity environments.
• Higher Maximum Drive Current: The improved heat dissipation allows for operation at the full 500mA continuous current, enabling higher lumen packages.
The trade-off is typically a slightly higher unit cost compared to plastic packages.

10. Frequently Asked Questions (FAQs)

Q1: What is the difference between the luminous flux 'Typ' and 'Min' values in the binning table?
A1: The 'Typ' (Typical) value is the average output for LEDs in that bin. The 'Min' (Minimum) value is the guaranteed lower limit. Designers should use the 'Min' value for worst-case brightness calculations in their application.

Q2: Can I drive this LED at 500mA continuously?
A2: Yes, 500mA is the absolute maximum DC rating. However, continuous operation at this level requires excellent thermal management to keep the junction temperature below 125°C. For optimal lifetime and efficiency, operating at 350mA or lower is recommended.

Q3: How do I interpret the voltage bin codes when designing my driver?
A3: Design your constant-current driver to accommodate the maximum V_F in your selected bin (e.g., for bin 'E', design for up to 2.4V per LED). If using a voltage source with a resistor, calculate the resistor value using the maximum V_F to ensure the current does not exceed the limit under worst-case conditions.

Q4: Is a lens included on this LED?
A4: The part number T1901PYA and the '00' code in the naming convention for 'no lens' suggest this is a primary optic (chip-level) LED without an integrated secondary lens. The 120° viewing angle is inherent to the chip and package design.

11. Design-in Case Study

Scenario: Designing an industrial high-bay light fixture requiring 5000 lumens of yellow light for a specific warning/signaling application.
Design Process:
1. Luminous Target: 5000 lm required.
2. LED Selection: Choose the 1Q flux bin (Min 50 lm/LED at 350mA).
3. Quantity Calculation: Number of LEDs = 5000 lm / 50 lm/LED = 100 LEDs. Add a 10% margin, target 110 LEDs.
4. Electrical Design: Plan to drive LEDs in series strings with a constant current driver. Select voltage bin 'D' (2.0-2.2V) for tighter distribution. For 10 LEDs in series, the maximum string voltage is 10 * 2.2V = 22V. Choose a constant current driver with an output voltage range covering up to ~25V and a 350mA output.
5. Thermal Design: Arrange 110 LEDs on a metal-core PCB (MCPCB). Calculate the total heat dissipation: ~110 LEDs * (2.2V * 0.35A) ≈ 84.7W of electrical power, most of which becomes heat. The MCPCB must be attached to a substantial aluminum heatsink to maintain a low thermal resistance from junction to ambient.
6. Optics: Since a wide 120° beam is acceptable for area lighting, no secondary optics are needed.

12. Operating Principle

Light Emitting Diodes (LEDs) are semiconductor devices that emit light when an electric current passes through them. This phenomenon is called electroluminescence. In a yellow LED like this one, the semiconductor material (typically based on Aluminum Gallium Indium Phosphide - AlGaInP) is engineered with a specific bandgap. When electrons recombine with electron holes within the device, energy is released in the form of photons (light particles). The wavelength (color) of the emitted light is determined by the energy bandgap of the semiconductor material. The ceramic package serves as a mechanical support, provides electrical connections, and most importantly, acts as an efficient heat sink to draw thermal energy away from the semiconductor junction, maintaining performance and reliability.

13. Technology Trends

The high-power LED market continues to evolve towards higher efficacy (more lumens per watt), improved color rendering, and greater reliability. Ceramic packages represent a significant trend in this space, especially for mid-to-high power applications, due to their unmatched thermal performance. Future developments may include:
• Integrated Solutions: More LEDs with built-in drivers or control circuitry (e.g., IC-on-board).
• Improved Phosphor Technology: For white LEDs, but also affecting the stability and efficiency of color-converted LEDs.
• Miniaturization with High Output: Continued push for smaller packages (e.g., 3030, 2929) capable of handling similar or higher power densities, further emphasizing the need for advanced thermal substrates like ceramics.
• Smart Lighting: Integration with sensors and communication protocols for IoT-enabled lighting systems, where the robust ceramic package can protect sensitive electronics.