LTST-C295TBKFKT-5A Dual Color SMD LED Datasheet - Package Dimensions - Blue 3.2V / Orange 2.3V - 0.55mm Height - English Technical Document

1. Product Overview

This document provides the complete technical specifications for the LTST-C295TBKFKT-5A, a dual-color, surface-mount LED component. The device integrates two distinct LED chips within a single, ultra-thin package: a blue-emitting InGaN chip and an orange-emitting AlInGaP chip. This design enables compact solutions for status indication, backlighting, and multi-signal applications where space is at a premium. The product is designed for compatibility with automated assembly processes and standard infrared reflow soldering, making it suitable for high-volume manufacturing environments.

1.1 Core Advantages and Target Market

The primary advantage of this component is its dual-color capability housed in an extra-thin 0.55mm profile. This allows for sophisticated visual signaling (e.g., different statuses indicated by different colors) without consuming additional PCB area. The use of ultra-bright InGaN and AlInGaP semiconductor materials ensures high luminous intensity. The device is RoHS compliant and classified as a green product. Its primary target markets include consumer electronics, office automation equipment, communication devices, and industrial control panels where reliable, multi-state indication is required.

2. Technical Parameter Deep-Dive

2.1 Absolute Maximum Ratings

These ratings define the stress limits beyond which permanent damage to the device may occur. Operating the LED under conditions exceeding these values is not recommended.

• Power Dissipation (Pd): Blue: 76 mW, Orange: 75 mW. This is the maximum allowable power the LED can dissipate as heat under DC conditions at 25°C ambient.
• Peak Forward Current (I_FP): Blue: 100 mA, Orange: 80 mA. This is the maximum permissible instantaneous forward current, typically specified under pulsed conditions (1/10 duty cycle, 0.1ms pulse width) to prevent overheating.
• DC Forward Current (I_F): Blue: 20 mA, Orange: 30 mA. This is the maximum continuous forward current recommended for reliable long-term operation.
• Electrostatic Discharge (ESD) Threshold (HBM): Blue: 300V, Orange: 1000V. The Human Body Model rating indicates the LED's sensitivity to static electricity. The blue chip is more sensitive, requiring stricter ESD handling precautions.
• Temperature Ranges: Operating: -20°C to +80°C; Storage: -30°C to +100°C.
• Infrared Soldering Condition: Withstands 260°C peak temperature for 10 seconds, which is standard for lead-free (Pb-free) reflow processes.

2.2 Electrical and Optical Characteristics

These are the typical and maximum/minimum performance parameters measured under standard test conditions (Ta=25°C, I_F=5mA unless noted).

• Luminous Intensity (I_V): For both colors, the minimum intensity is 18.0 mcd and the maximum is 45.0 mcd at 5mA. The typical value is not specified, falling within the min/max range.
• Viewing Angle (2θ_1/2): A wide 130-degree typical viewing angle for both colors, providing a broad emission pattern suitable for many indication applications.
• Peak Emission Wavelength (λ_P): Blue: 468 nm (typical), Orange: 611 nm (typical). This is the wavelength at which the spectral power distribution is highest.
• Dominant Wavelength (λ_d): Blue: 470 nm (typical), Orange: 605 nm (typical). This is the single wavelength perceived by the human eye, defining the color point on the CIE chromaticity diagram.
• Spectral Line Half-Width (Δλ): Blue: 20 nm (typical), Orange: 17 nm (typical). This indicates the spectral purity or bandwidth of the emitted light.
• Forward Voltage (V_F): Blue: 3.2V (max at 5mA), Orange: 2.3V (max at 5mA). This is a critical parameter for circuit design, determining the required drive voltage and series resistor value.
• Reverse Current (I_R): 10 µA (max) for both colors at V_R = 5V. The device is not designed for reverse bias operation; this parameter is for leakage characterization only.

3. Binning System Explanation

The luminous intensity of the LEDs is sorted into bins to ensure consistency within a production lot. The binning is identical for both the blue and orange chips.

• Bin Code M: Luminous Intensity range from 18.0 mcd to 28.0 mcd at 5mA.
• Bin Code N: Luminous Intensity range from 28.0 mcd to 45.0 mcd at 5mA.
• Tolerance: Each intensity bin has a tolerance of +/-15%. This means an LED labeled as Bin M could measure as low as 15.3 mcd or as high as 32.2 mcd and still be within the M bin specification, though it would typically be centered around the 18-28 mcd range.

This system allows designers to select LEDs with predictable brightness levels. For applications requiring uniform appearance, specifying a single bin code is essential.

4. Performance Curve Analysis

While specific graphical data is referenced in the datasheet (pages 6-7), the typical relationships can be described based on standard LED physics and the provided parameters.

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

The I-V characteristic is exponential. For the blue LED, the forward voltage is higher (~3.2V max) due to the wider bandgap of the InGaN material system. The orange AlInGaP LED has a lower forward voltage (~2.3V max). The voltage will increase slightly with rising junction temperature for a given current.

4.2 Luminous Intensity vs. Forward Current

Luminous intensity is approximately proportional to forward current within the recommended operating range (up to I_F=20/30mA). Driving the LED above its absolute maximum DC current will cause non-linear saturation and accelerated degradation due to excessive heat.

4.3 Temperature Dependence

LED performance is temperature-sensitive. As junction temperature increases, luminous intensity typically decreases. The forward voltage for a given current also decreases slightly for most LED materials. Operating within the specified temperature range (-20°C to +80°C) is crucial for maintaining specified performance and reliability.

5. Mechanical and Package Information

5.1 Package Dimensions and Pin Assignment

The LED is housed in an industry-standard SMD package. The exact dimensional drawing is provided in the datasheet. Key features include an overall height of 0.55mm, making it suitable for very thin applications. The pin assignment is as follows: Pins 1 and 3 are for the Blue (InGaN) chip anode/cathode, and Pins 2 and 4 are for the Orange (AlInGaP) chip anode/cathode. The specific anode/cathode designation for each pair must be determined from the package marking or footprint diagram.

5.2 Suggested Soldering Pad Layout

A recommended land pattern (soldering pad dimensions) is provided to ensure proper solder joint formation, mechanical stability, and thermal relief during reflow. Following this guideline helps prevent tombstoning (component standing up on one end) and ensures reliable electrical connection.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Profile

A suggested infrared reflow profile for lead-free processes is included. Key parameters include a pre-heat stage (150-200°C, max 120 seconds), a peak temperature not exceeding 260°C, and a time above 260°C limited to a maximum of 10 seconds. The profile is based on JEDEC standards to ensure package integrity. The LED can withstand this reflow process a maximum of two times.

6.2 Hand Soldering

If hand soldering is necessary, a soldering iron temperature must not exceed 300°C, and the soldering time per lead should be limited to a maximum of 3 seconds. Hand soldering should be performed only once.

6.3 Storage and Handling

ESD Precautions: The blue chip is sensitive to ESD (300V HBM). Proper anti-static measures (wrist straps, grounded workstations) are mandatory during handling.
Moisture Sensitivity: LEDs in sealed moisture-proof bags with desiccant have a shelf life of one year when stored at ≤30°C and ≤90% RH. Once the bag is opened, components should be stored at ≤30°C and ≤60% RH and used within one week. If stored longer out of the original bag, a 60°C bake for at least 20 hours is recommended before soldering to remove absorbed moisture and prevent \"popcorning\" during reflow.

6.4 Cleaning

If cleaning after soldering is required, only specified solvents should be used. Immersing the LED in ethyl alcohol or isopropyl alcohol at room temperature for less than one minute is acceptable. Unspecified chemicals may damage the plastic package or lens.

7. Packaging and Ordering Information

The LEDs are supplied in tape-and-reel packaging compatible with automated pick-and-place machines.

• Reel Size: 7-inch diameter reel.
• Quantity per Reel: 4000 pieces.
• Minimum Order Quantity (MOQ): 500 pieces for remainder quantities.
• Tape Specifications: The carrier tape is 8mm wide. Empty pockets are sealed with cover tape. Packaging conforms to ANSI/EIA-481 specifications.
• Quality: The maximum allowable number of consecutive missing components in the tape is two.

8. Application Suggestions

8.1 Typical Application Scenarios

• Status Indicators: Dual-color capability allows for multiple statuses (e.g., Blue=Standby, Orange=Active, Both=Warning/Fault).
• Backlighting for Keypads or Icons: Can provide color-coded backlighting.
• Consumer Electronics: Power, connectivity, or battery status indicators in smartphones, tablets, routers, and audio equipment.
• Industrial Control Panels: Machine status, operational mode, or alarm indicators.

8.2 Design Considerations

• Current Limiting: Always use a series resistor for each LED chip to limit the forward current to a safe value (≤20mA for blue, ≤30mA for orange under DC operation). The resistor value is calculated as R = (V_supply - V_F) / I_F.
• Thermal Management: Ensure adequate PCB copper area or thermal vias, especially if driving near maximum current, to dissipate heat and maintain junction temperature within limits.
• ESD Protection: Incorporate ESD protection diodes on signal lines connected to the LED pins if the assembly environment or end-use scenario poses an ESD risk.
• Optical Design: The wide 130-degree viewing angle provides good off-axis visibility. For directed light, external lenses or light guides may be necessary.

9. Technical Comparison and Differentiation

The key differentiating factors of this component are its dual-color functionality in an ultra-thin 0.55mm package. Compared to using two separate single-color LEDs, this saves significant PCB area and simplifies assembly. The combination of InGaN (blue) and AlInGaP (orange) technologies provides high efficiency and brightness for both colors. The product's compatibility with standard SMT processes and Pb-free reflow makes it a drop-in solution for modern electronics manufacturing.

10. Frequently Asked Questions (Based on Technical Parameters)

Q1: Can I drive both the blue and orange LEDs simultaneously at their maximum DC current?
A1: No. The power dissipation ratings (76mW blue, 75mW orange) and thermal design of the package must be considered. Driving both chips at full DC current simultaneously would likely exceed the package's total thermal capacity unless exceptional cooling is provided. It is advisable to consult thermal derating curves or operate at lower currents for simultaneous use.

Q2: Why is the ESD rating for the blue chip (300V) lower than for the orange chip (1000V)?
A2: This is due to the inherent material properties and junction structure of the InGaN semiconductor used for blue emission. It is generally more susceptible to electrostatic discharge damage than the AlInGaP material used for orange/red emission. This necessitates extra care when handling the blue channel.

Q3: How do I interpret the Bin Code for ordering?
A3: Specify \"LTST-C295TBKFKT-5A\" along with the desired intensity bin code (e.g., \"N\" for higher brightness) for each color if the supplier offers bin selection. For consistent brightness across a production run, specifying a single bin is critical.

11. Practical Design and Usage Case

Case: Designing a Dual-Status Power Indicator for a Router
**Objective:** Use one LED to indicate Power (Orange) and Internet Connectivity (Blue).
**Design:** The LED is placed on the router's front panel. The microcontroller (MCU) has two GPIO pins, each connected to one LED channel via a current-limiting resistor.
**Calculations:** For a 5V supply:
- Orange Resistor: R_orange = (5V - 2.3V) / 0.020A = 135 Ω (use 130 Ω or 150 Ω standard value). Power: P = I²R = (0.02)²*150 = 0.06W.
- Blue Resistor: R_blue = (5V - 3.2V) / 0.020A = 90 Ω (use 91 Ω standard value). Power: P = (0.02)²*91 = 0.0364W.
**Operation:** The MCU drives the Orange pin for solid light when powered on. It drives the Blue pin to blink when internet connectivity is active. Both are never driven continuously at full current simultaneously for extended periods, managing thermal load.

12. Technology Principle Introduction

This LED utilizes two different semiconductor material systems:
InGaN (Indium Gallium Nitride): Used for the blue emitter. By adjusting the ratio of indium to gallium in the alloy, the bandgap energy can be tuned, which directly determines the wavelength of emitted light. InGaN is known for high efficiency and brightness in the blue to green spectrum.
AlInGaP (Aluminum Indium Gallium Phosphide): Used for the orange emitter. This material system is highly efficient for producing light in the amber, orange, red, and yellow wavelengths. The specific composition determines the dominant wavelength.
In both cases, light is emitted through the process of electroluminescence. When a forward voltage is applied across the p-n junction, electrons and holes recombine, releasing energy in the form of photons (light). The color of the light is determined by the bandgap energy of the semiconductor material.

13. Technology Development Trends

The trend in SMD LEDs like this one continues toward:
Higher Efficiency (lm/W): Ongoing improvements in epitaxial growth, chip design, and package extraction efficiency lead to more light output for the same electrical input power.
Miniaturization: Packages continue to shrink in footprint and height (like the 0.55mm profile here) to enable thinner end products.
Multi-Chip and RGB Integration: Beyond dual-color, packages integrating red, green, and blue (RGB) chips or even white + colored chips are becoming common for full-color programmability.
Improved Reliability and Thermal Performance: Advances in materials (e.g., high-temperature plastics, advanced die-attach) enhance the ability to withstand higher reflow temperatures and operating conditions.
Intelligent Packaging: Some LEDs now incorporate integrated circuits (ICs) for driver control or communication (e.g., addressable RGB LEDs), though this particular component is a standard, driver-less LED.