T3B Series 3014 Dual Chip 0.25W White LED Datasheet - Size 3.0x1.4x0.8mm - Voltage 6.3V - Power 0.25W - English Technical Document

1. Product Overview

The T3B series represents a family of surface-mount device (SMD) LEDs utilizing a 3014 package footprint. The defining characteristic of this series is the integration of two LED chips connected in series within a single package. This configuration is designed for applications requiring a higher forward voltage than typical single-die LEDs, while maintaining a compact form factor. The primary application is in backlighting units, indicator lights, and general illumination where space is constrained and specific voltage compatibility is needed.

The core advantage of the dual-chip series configuration is the increased forward voltage (Vf). Operating at a nominal 6.3V at 40mA, it simplifies driver design for systems already supplying voltages in the 6-7V range, potentially eliminating the need for additional voltage step-down circuitry. The 3014 package (3.0mm x 1.4mm x 0.8mm) offers a good balance between light output and board space utilization.

2. Technical Parameters and Objective Interpretation

2.1 Absolute Maximum Ratings

The device's operational limits are defined under conditions where the solder point temperature (Ts) is maintained at 25\u00b0C. Exceeding these ratings may cause permanent damage.

• Forward Current (IF): 60 mA (Continuous)
• Forward Pulse Current (IFP): 80 mA (Pulse width \u2264 10ms, Duty cycle \u2264 1/10)
• Power Dissipation (PD): 408 mW
• Operating Temperature (Topr): -40\u00b0C to +80\u00b0C
• Storage Temperature (Tstg): -40\u00b0C to +100\u00b0C
• Junction Temperature (Tj): 125\u00b0C
• Soldering Temperature (Tsld): Reflow soldering at 230\u00b0C or 260\u00b0C for a maximum of 10 seconds.

2.2 Electro-Optical Characteristics (Typical at Ts=25\u00b0C, IF=40mA)

These parameters define the expected performance under normal operating conditions.

• Forward Voltage (VF): 6.3 V (Typical), 6.8 V (Maximum). The series connection of two chips results in this higher Vf.
• Reverse Voltage (VR): 5 V
• Reverse Current (IR): 10 \u00b5A (Maximum)
• Viewing Angle (2\u03b81/2): 120\u00b0. This wide beam angle is typical for the 3014 package without a secondary lens.

3. Binning System Explanation

The product is classified according to several key parameters to ensure consistency and meet design requirements. The ordering code follows a specific structure to select these bins.

3.1 Model Numbering Rule

The naming convention is: T [Package Code] [Chip Count Code] [Lens Code] [Internal Code] - [Luminous Flux Code] [CCT Code]. For example, T3B002LWA decodes as: T-series, 3014 package (3B), dual chip (2), no lens (00), internal code 2, specific luminous flux bin, Cool White (W).

3.2 Correlated Color Temperature (CCT) Binning

White LEDs are binned into specific chromaticity regions defined by ellipses on the CIE 1931 chromaticity diagram. The standard ordering bins are:

• 27M5: 2725K \u00b1 145K
• 30M5: 3045K \u00b1 175K
• 40M5: 3985K \u00b1 275K
• 50M5: 5028K \u00b1 283K
• 57M5: 5665K \u00b1 355K
• 65M5: 6530K \u00b1 510K

The \"M5\" and \"M7\" suffixes refer to the MacAdam ellipse step (5-step or 7-step), indicating the tolerance of color consistency. A smaller step number denotes tighter color control.

3.3 Luminous Flux Binning

Flux is specified as a minimum value at 40mA. The typical and maximum values may be higher. Binning is combined with CCT and Color Rendering Index (CRI).

• Warm White (2700-3700K), CRI 70: Min. 28 lm
• Neutral White (3700-5000K), CRI 70: Min. 30 lm
• Cool White (5000-7000K), CRI 70: Min. 32 lm
• Warm White, CRI 80+: Min. 26 lm
• Neutral White, CRI 80+: Min. 28 lm
• Cool White, CRI 80+: Min. 30 lm

3.4 Forward Voltage Binning

The standard voltage bin is 6.0V to 6.5V. The typical value is 6.3V. This binning helps in designing constant-current drivers with appropriate voltage headroom.

4. Performance Curve Analysis

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

The I-V curve for the dual-chip LED will show a turn-on voltage approximately double that of a single chip. The curve is exponential initially, becoming more linear above the turn-on point. Designers must ensure the driver can provide the required voltage, especially at low temperatures where Vf increases.

4.2 Relative Luminous Flux vs. Forward Current

Light output increases with current but not linearly. Efficiency typically peaks at a certain current and then decreases due to increased thermal effects and droop. Operating at the recommended 40mA ensures optimal efficiency and longevity.

4.3 Spectral Power Distribution

The white light is generated by a blue LED chip exciting a phosphor layer. The spectral curve shows a dominant blue peak from the chip and a broader yellow/red emission from the phosphor. The ratio and width of the phosphor emission determine the CCT and CRI. Cool white LEDs have a more prominent blue peak, while warm white LEDs have stronger longer-wavelength phosphor emission.

4.4 Relative Luminous Flux vs. Junction Temperature

LED light output decreases as junction temperature (Tj) rises. This characteristic is crucial for thermal management design. Effective heat sinking is necessary to maintain Tj as low as possible to ensure stable light output and long lifespan.

4.5 Spatial Radiation Pattern (Viewing Angle)

The 120-degree viewing angle represents the angular width at which the luminous intensity is half of the peak intensity (0-degree axis). The radiation pattern for a 3014 package is typically Lambertian or near-Lambertian, providing even, wide-area illumination suitable for panel lighting.

5. Mechanical and Packaging Information

5.1 Package Dimensions

The 3014 package dimensions are 3.0mm (L) \u00b1 0.1mm x 1.4mm (W) \u00b1 0.1mm x 0.8mm (H) \u00b1 0.1mm. The lens is typically silicone-based.

5.2 Pad Layout and Stencil Design

The recommended footprint includes two anode pads and two cathode pads. The solder pad design is critical for proper reflow, mechanical stability, and thermal conduction. The provided stencil pattern ensures the correct volume of solder paste is deposited for reliable solder joint formation. Tolerances for pad dimensions are \u00b10.1mm for one-decimal-place values and \u00b10.05mm for two-decimal-place values.

5.3 Polarity Identification

The cathode side of the LED is typically marked, often with a green tint on the substrate or a notch/chamfer on the package. Correct polarity must be observed during assembly to prevent reverse bias damage.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Profile

The component is rated for lead-free reflow soldering. Two profiles are acceptable: a peak temperature of 230\u00b0C or 260\u00b0C, with the time above liquidus (typically ~217\u00b0C) controlled to a maximum of 10 seconds at peak temperature. A standard ramp-up, soak, reflow, and cooling profile should be followed to minimize thermal stress.

6.2 Moisture Sensitivity and Baking

The 3014 package is moisture-sensitive (MSL). If the original vacuum-sealed bag is opened and the LEDs are exposed to ambient humidity (indicated by the humidity indicator card turning pink), they must be baked before reflow to prevent \"popcorn\" damage during soldering.

• Baking Condition: 60\u00b0C for 24 hours.
• Post-Baking: LEDs should be soldered within 1 hour or stored in a dry cabinet (<20% RH).
• Do not bake at temperatures exceeding 60\u00b0C.

6.3 Storage Conditions

• Unopened Bag: Temperature 5-30\u00b0C, Humidity <85%.
• After Opening: Temperature 5-30\u00b0C, Humidity <60%. For long-term storage, use a sealed container with desiccant or a nitrogen cabinet.
• Floor Life: It is recommended to use the components within 12 hours after opening the moisture barrier bag under factory floor conditions (<60% RH).

7. Application Suggestions and Design Considerations

7.1 Typical Application Scenarios

• LCD Backlighting: For TVs, monitors, and signage, where the higher Vf can match driver outputs.
• General Decorative Lighting: Strips, modules, and accent lighting.
• Indicator Lights: In appliances and industrial equipment requiring bright, reliable status indication.

7.2 Driver Design

Use a constant current driver rated for the required current (e.g., 40mA) with a voltage compliance range that accommodates the maximum Vf of the LED string, including tolerances and temperature effects. For multiple LEDs, connect them in series, parallel, or series-parallel configurations based on the driver capability and required redundancy.

7.3 Thermal Management

Although power is only 0.25W, effective thermal management on the PCB is essential to maintain low junction temperature. Use a PCB with thermal vias under the LED's thermal pad (if present) connected to a copper pour or an internal ground plane to dissipate heat. This maximizes light output stability and operational lifetime.

8. Technical Comparison and Differentiation

Compared to a standard 3014 single-die LED (typically Vf ~3.0-3.4V), the T3B dual-die series offers a key differentiation: a higher forward voltage. This can be an advantage or a requirement depending on the system architecture.

• Advantage: Simplifies design in systems with 6V/12V rails, reducing or eliminating buck converters. Allows longer series strings for a given driver voltage.
• Consideration: Requires a driver with higher voltage capability. Power dissipation per package is slightly higher due to the higher Vf at the same current, necessitating attention to thermal design.
• Compared to a 5730 or 5050 package with similar power, the 3014 offers a smaller footprint but may have different thermal and optical characteristics.

9. Frequently Asked Questions (Based on Technical Parameters)

Q: Can I drive this LED at 60mA continuously?
A: While the absolute maximum rating is 60mA, the recommended operating current is 40mA. Operating at 60mA will significantly increase junction temperature, reduce efficiency (lumen/Watt), and potentially shorten the LED's lifespan. It should only be considered if robust thermal management is implemented and the reduced lifetime is acceptable.

Q: What is the difference between the 27M5 and 30M5 CCT bins?
A: 27M5 targets a warmer white light around 2725K, while 30M5 is around 3045K, which is still warm but slightly less orange/red. The \"M5\" indicates both are sorted to within a 5-step MacAdam ellipse, meaning very good color consistency within each bin.

Q: Why is baking necessary, and what happens if I skip it?
A: The plastic package absorbs moisture. During the high-temperature reflow soldering process, this trapped moisture rapidly turns to steam, creating internal pressure that can delaminate the package, crack the die, or break wire bonds, leading to immediate or latent failure (popcorn effect).

Q: How do I interpret the luminous flux \"min\" value?
A: When you order a specific flux bin (e.g., 30 lm min for Neutral White), you are guaranteed that all LEDs will meet or exceed that value under test conditions. The actual shipped parts may have higher output, but they will always fall within the specified CCT chromaticity ellipse.

10. Practical Design and Usage Case

Case: Designing a 12V LED Module for Cabinet Lighting
A designer needs to create a slim, bright module powered directly from a 12V DC adapter. Using standard 3V LEDs would require 4 in series, leaving little voltage headroom for the constant-current driver, especially at low temperatures. Using the T3B dual-chip LEDs with a Vf of ~6.3V allows two LEDs to be connected in series. This 2S configuration has a nominal Vf of 12.6V, which is a good match for a 12V supply when using a simple linear or switching constant-current driver with low dropout. This simplifies the circuit, reduces component count, and fits the mechanical constraints better than a 4S string of smaller LEDs.

11. Operating Principle

An LED is a semiconductor diode. When a forward voltage exceeding its bandgap energy is applied, electrons and holes recombine in the active region, releasing energy in the form of photons (light). In a white LED, a blue-emitting indium gallium nitride (InGaN) chip is coated with a cerium-doped yttrium aluminum garnet (YAG:Ce) phosphor. Some of the blue light is absorbed by the phosphor and re-emitted as yellow light. The mixture of the remaining blue light and the converted yellow light is perceived by the human eye as white. The correlated color temperature is adjusted by modifying the phosphor composition and concentration. The dual-chip design simply places two such semiconductor structures electrically in series inside one package.

12. Technology Trends

The general trend in SMD LEDs is toward higher efficiency (more lumens per watt), improved color rendering (higher CRI and R9 values), better color consistency (tighter binning, e.g., 3-step or 2-step MacAdam ellipses), and higher reliability. There is also a drive for miniaturization while maintaining or increasing light output. The use of dual-chip or multi-chip designs in standard packages like 3014 or 2835 is a method to offer application-specific electrical characteristics (like higher Vf) without changing the external mechanical footprint, providing designers with more flexibility. Furthermore, advancements in phosphor technology and chip design continue to push the boundaries of efficacy and color quality across all CCT ranges.