T12 Series Flip Chip LED Specification - 10W White - 9 LEDs in Series - English Technical Document

1. Product Overview

The T12 series represents a high-power, surface-mount LED module utilizing flip-chip technology. This document details the specifications for a 10W white light variant configured with 9 LED chips connected in series. Flip-chip design offers enhanced thermal performance and reliability by directly attaching the semiconductor die to the substrate, improving heat dissipation and reducing thermal resistance.

This LED module is engineered for applications demanding high luminous output and robust performance, such as industrial lighting, high-bay fixtures, outdoor area lighting, and specialized luminaires. Its series configuration simplifies driver design by requiring a higher forward voltage at a controlled current.

2. Technical Parameter Deep-Dive Analysis

2.1 Absolute Maximum Ratings (T_s=25°C)

The following parameters define the operational limits beyond which permanent damage to the LED may occur. These are not recommended operating conditions.

• Forward Current (I_F): 700 mA (DC)
• Forward Pulse Current (I_FP): 700 mA (Pulse Width ≤10ms, Duty Cycle ≤1/10)
• Power Dissipation (P_D): 20300 mW (20.3W)
• Operating Temperature (T_opr): -40°C to +100°C
• Storage Temperature (T_stg): -40°C to +100°C
• Junction Temperature (T_j): 125°C (Maximum)
• 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)

These are the typical and maximum values under specified test conditions, representing the expected performance.

• Forward Voltage (V_F): Typical 27V, Maximum 29V (at I_F=350mA). The high voltage is due to the 9-series configuration.
• Reverse Voltage (V_R): 5V (Maximum)
• Reverse Current (I_R): 100 µA (Maximum) at V_R=5V.
• Viewing Angle (2θ_1/2): 130° (Typical). This indicates a wide beam pattern suitable for area illumination.

3. Binning System Explanation

3.1 Correlated Color Temperature (CCT) Binning

The product is offered in standard CCT bins. Each bin corresponds to a specific chromaticity region on the CIE diagram, ensuring color consistency within a batch. The standard ordering options are:

• 2700K: Chromaticity regions 8A, 8B, 8C, 8D (Warm White)
• 3000K: Chromaticity regions 7A, 7B, 7C, 7D (Warm White)
• 3500K: Chromaticity regions 6A, 6B, 6C, 6D (Neutral White)
• 4000K: Chromaticity regions 5A, 5B, 5C, 5D (Neutral White)
• 4500K: Chromaticity regions 4A, 4B, 4C, 4D, 4R, 4S, 4T, 4U (Cool White)
• 5000K: Chromaticity regions 3A, 3B, 3C, 3D, 3R, 3S, 3T, 3U (Cool White)
• 5700K: Chromaticity regions 2A, 2B, 2C, 2D, 2R, 2S, 2T, 2U (Daylight)
• 6500K: Chromaticity regions 1A, 1B, 1C, 1D, 1R, 1S, 1T, 1U (Daylight)

Note: The binning defines the allowable color coordinate range, not a single point.

3.2 Luminous Flux Binning

Luminous flux is binned based on minimum values at a test current of 350mA. The actual flux may exceed the minimum ordered value but will remain within the specified CCT bin.

• Warm White (2700K-3700K), CRI ≥70:
  • Code 3H: 800 lm (Min), 900 lm (Typ)
  • Code 3J: 900 lm (Min), 1000 lm (Typ)
• Neutral White (3700K-5000K), CRI ≥70:
  • Code 3H: 800 lm (Min), 900 lm (Typ)
  • Code 3J: 900 lm (Min), 1000 lm (Typ)
• Cool White (5000K-10000K), CRI ≥70:
  • Code 3J: 900 lm (Min), 1000 lm (Typ)
  • Code 3K: 1000 lm (Min), 1100 lm (Typ)

Tolerances: Luminous flux: ±7%; CRI (Color Rendering Index): ±2; Chromaticity coordinates: ±0.005.

4. Performance Curve Analysis

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

The I-V curve is non-linear, typical of a diode. At the recommended operating current of 350mA, the typical forward voltage is 27V. The curve shows that a small increase in voltage beyond the knee point leads to a rapid increase in current, highlighting the importance of constant-current drive for stable operation and longevity.

4.2 Forward Current vs. Relative Luminous Flux

This curve demonstrates the relationship between drive current and light output. Luminous flux increases approximately linearly with current in the normal operating range. However, driving the LED at currents higher than recommended (e.g., 700mA) may yield diminishing returns in efficiency (efficacy in lm/W) and significantly increase junction temperature, accelerating lumen depreciation and reducing lifespan.

4.3 Junction Temperature vs. Relative Spectral Power

As the junction temperature (T_j) increases, the spectral power distribution of a white LED (typically a blue die with phosphor) can shift. This often manifests as a decrease in radiant power at certain wavelengths and a potential change in the correlated color temperature (CCT). Effective thermal management is crucial to maintain stable color and light output over time.

4.4 Relative Spectral Power Distribution

The spectral curve for a white LED shows a dominant peak in the blue region (from the InGaN chip) and a broader emission band in the yellow/green/red region (from the phosphor coating). The exact shape determines the CCT and CRI. A broader and smoother phosphor emission contributes to a higher CRI.

5. Mechanical and Packaging Information

5.1 Package Outline Drawing

The physical dimensions of the LED module are provided in the datasheet diagram. Key mechanical features include the overall length, width, and height, as well as the location and size of the solder pads. The package is designed for surface-mount technology (SMT) assembly.

5.2 Recommended Pad Pattern and Stencil Design

Detailed drawings for the PCB land pattern (footprint) and solder paste stencil are provided. Adherence to these recommendations is critical for achieving proper solder joint formation, alignment, and reliable mechanical attachment. The pad design ensures correct electrical connection and aids in heat transfer from the LED to the PCB. Tolerance for these dimensions is typically ±0.10mm.

Polarity Identification: The anode (+) and cathode (-) terminals are clearly marked on the package or indicated in the footprint diagram. Correct polarity is essential for operation.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Parameters

The LED is compatible with standard infrared or convection reflow soldering processes. The maximum permissible body temperature during soldering is 230°C or 260°C, with the exposure time at peak temperature not exceeding 10 seconds. It is crucial to follow a temperature profile that preheats the assembly adequately to minimize thermal shock.

6.2 Handling and Storage Precautions

• ESD Sensitivity: LEDs are static-sensitive devices. Use appropriate ESD precautions during handling and assembly.
• Moisture Sensitivity: The package may have a moisture sensitivity level (MSL). If specified, adhere to the baking and floor life requirements before reflow.
• Storage Conditions: Store in a dry, dark environment within the specified temperature range (-40°C to +100°C). Avoid exposure to corrosive gases.
• Cleaning: If cleaning is necessary post-solder, use compatible solvents and methods that do not damage the LED lens or silicone material.

7. Application Suggestions

7.1 Typical Application Scenarios

• High-Bay and Industrial Lighting: Leverages high lumen output and robust construction.
• Outdoor Area Lighting: Street lights, parking lot lights, stadium lighting.
• High-Flux Specialized Luminaires: Grow lights, projectors, stage lighting.
• Architectural and Commercial Lighting: Where high efficiency and long life are prioritized.

7.2 Design Considerations

• Thermal Management: This is the single most critical factor for performance and lifetime. Design the PCB and heatsink to keep the LED junction temperature (T_j) well below the maximum rating of 125°C, ideally below 85°C for optimal lifetime. Use thermal vias, metal-core PCBs (MCPCBs), or active cooling as needed.
• Drive Current: Use a constant-current LED driver rated for the required voltage range (based on V_F). Operating at or below the typical 350mA current is recommended for a balance of output, efficiency, and lifespan. Derating the current increases lifetime significantly.
• Optical Design: The wide 130° viewing angle may require secondary optics (lenses, reflectors) to achieve the desired beam pattern for the application.
• Electrical Protection: Consider protection against reverse polarity, over-voltage transients, and electrostatic discharge (ESD) on the input lines.

8. Technical Comparison and Differentiation

Flip-Chip vs. Traditional Wire-Bonded LED:

• Thermal Performance: Flip-chip attachment provides a shorter, more direct thermal path from the active junction to the substrate/heat sink, resulting in lower thermal resistance (R_th). This allows for higher drive currents or improved lifetime at the same current.
• Reliability: Eliminates wire bonds, which can be points of failure due to thermal cycling, vibration, or electromigration.
• Current Spreading: Often incorporates a better current-spreading layer under the die, leading to more uniform light emission and potentially higher efficiency.
• Optical Design: Can allow for a more compact package or different light extraction features.

Series Configuration (9-in-Series): Simplifies driver design for high-voltage, low-current applications, often improving driver efficiency compared to driving multiple parallel strings.

9. Frequently Asked Questions (FAQs)

9.1 What is the recommended operating current?

The datasheet specifies characteristics at 350mA, which is the typical recommended operating point. It can be driven up to the absolute maximum of 700mA, but this will significantly increase junction temperature and reduce lifespan. For optimal lifetime and efficiency, operation at or below 350mA is advised.

9.2 Why is the forward voltage so high (~27V)?

The module contains 9 individual LED chips connected in series. The forward voltages of each chip add up. A typical white LED chip has a V_F of around 3V; 9 * 3V = 27V.

9.3 How do I select the correct CCT bin?

Choose the nominal CCT (e.g., 4000K) based on your application's required ambiance and color rendering. The associated chromaticity regions (e.g., 5A-5D) ensure color consistency. For critical color-matching applications, request tighter binning or select from a single production batch.

9.4 What heatsink is required?

The required heatsink depends on your operating current, ambient temperature, desired T_j, and the thermal resistance of your PCB and interface materials. You must perform a thermal calculation based on the total power dissipation (V_F * I_F) and the target thermal resistance from junction to ambient (R_θJA).

9.5 Can I use PWM for dimming?

Yes, pulse-width modulation (PWM) is an effective dimming method for LEDs. Ensure the PWM frequency is sufficiently high (typically >100Hz) to avoid visible flicker. The driver should be designed for PWM input or have a dedicated dimming interface.

10. Practical Design Case Study

Scenario: Designing a 100W high-bay luminaire using multiple T12 modules.

Design Steps:

1. Module Count: Target 100W total. Each module at 350mA consumes ~9.45W (27V * 0.35A). Use 10 modules for ~94.5W.
2. Driver Selection: Need a constant-current driver for 10 series-connected modules. Required output voltage range: 10 * (27V to 29V) = 270V to 290V. Required current: 350mA. Select a driver rated for >290V, 350mA.
3. Thermal Design: Total dissipation ~94.5W. Use a metal-core PCB (MCPCB) mounted to a large aluminum heatsink. Calculate the required R_θSA (sink-to-ambient) based on max ambient temp (e.g., 50°C) and target T_j (e.g., 90°C), factoring in R_θJC and R_θCS from the LED and interface.
4. Optics: For a high-bay, a medium beam angle (e.g., 60°-90°) is often desired. Select secondary lenses or reflectors compatible with the module's footprint to narrow the beam from the native 130°.
5. PCB Layout: Follow the recommended pad layout. Ensure thick copper traces for current carrying. Implement thermal relief patterns for soldering but maximize copper pour for heat spreading.

11. Technology Principle Introduction

Flip-Chip LED Technology: In a conventional LED, the semiconductor layers are grown on a substrate, and electrical connections are made via wire bonds to the top of the die. In a flip-chip design, after growth, the die is "flipped" over and bonded directly onto a carrier substrate (like a ceramic or silicon sub-mount) using solder bumps. This places the active light-emitting region closer to the thermal path. Light is emitted through the substrate (which must be transparent, like sapphire) or through the side if the substrate is removed. This structure improves heat dissipation, allows for higher current density, and enhances reliability by removing fragile wire bonds.

White Light Generation: Most white LEDs use a blue-emitting indium gallium nitride (InGaN) chip. Part of the blue light is absorbed by a layer of phosphor material (typically yttrium aluminum garnet doped with cerium, YAG:Ce) coated on or around the chip. The phosphor down-converts some blue light into yellow light. The mixture of the remaining blue light and the generated yellow light is perceived by the human eye as white. Adjusting the phosphor composition and thickness controls the CCT and CRI.

12. Industry Trends and Development

Efficiency (lm/W) Growth: The primary trend continues to be increasing luminous efficacy, reducing the energy required per unit of light. This is achieved through improvements in internal quantum efficiency (IQE), light extraction efficiency, and phosphor conversion efficiency.

High Power Density & Miniaturization: There is a push towards packing more lumens into smaller packages, driven by applications like automotive headlights, micro-projectors, and ultra-compact luminaires. Flip-chip and chip-scale package (CSP) technologies are key enablers.

Improved Color Quality and Consistency: Demand for high CRI (Ra >90, R9 >50) and consistent color point across batches and over lifetime is increasing, especially in retail, museum, and healthcare lighting.

Reliability and Lifetime: Focus on understanding and mitigating failure mechanisms under high-temperature, high-humidity, and high-current stress conditions to guarantee longer L70/B50 lifetimes (time to 70% lumen maintenance for 50% of population).

Smart and Connected Lighting: Integration of control electronics, sensors, and communication interfaces directly with LED modules is becoming more common, enabling IoT-based lighting systems.

Specialized Spectra: Development of LEDs with tailored spectral outputs for human-centric lighting (HCL), horticulture (grow lights), and medical applications.