LTST-C281KFKT Orange LED Datasheet - 0.35mm Ultra-Thin Height - 2.4V Forward Voltage - 75mW Power Dissipation - Technical Documentation

1. Product Overview

LTST-C281KFKT is a surface-mount device (SMD) light-emitting diode (LED) designed for modern electronic applications requiring compact, high-brightness indicator lights. This device belongs to the chip LED category, characterized by an extremely slim profile and compatibility with automated assembly processes.

Core Advantages:The primary advantages of this LED include its ultra-thin package height of 0.35 mm, facilitating use in space-constrained designs. It utilizes AlInGaP (aluminum indium gallium phosphide) semiconductor material, renowned for generating high luminous efficiency and stable orange light output. The device complies with the RoHS (Restriction of Hazardous Substances) directive, classifying it as an environmentally friendly product. It is packaged on an 8 mm carrier tape with a 7-inch diameter reel, fully compatible with high-speed automatic placement equipment, simplifying mass manufacturing processes.

Target Market:This LED primarily targets applications requiring reliable, bright status indication, such as consumer electronics, office automation equipment, communication devices, and general household appliances. Its design parameters make it suitable for integration onto PCBs (Printed Circuit Boards) using standard infrared reflow soldering techniques.

2. Detailed Technical Parameters

2.1 Absolute Maximum Ratings

These ratings define the limits beyond which permanent damage to the device may occur. Operation under these conditions is not guaranteed.

• Power Dissipation (Pd):75 mW. This is the maximum power that the LED package can dissipate as heat under specified ambient conditions (Ta=25°C). Exceeding this limit risks thermal degradation.
• Peak Forward Current (I_FP):80 mA. This is the maximum permissible instantaneous forward current, allowed only under pulse conditions (1/10 duty cycle, 0.1 ms pulse width). It is significantly higher than the DC rating to accommodate brief current surges.
• DC Forward Current (I_F):30 mA. This is the maximum continuous forward current recommended for reliable long-term operation. The typical operating condition for testing optical characteristics is 20 mA.
• Reverse voltage (V_R):5 V. Applying a reverse bias exceeding this value may cause junction breakdown.
• Operating and storage temperature:The device can operate within an ambient temperature range of -30°C to +85°C. For non-operating storage, the temperature range extends to -40°C to +85°C.
• Welding Conditions:This LED can withstand infrared reflow soldering with a peak temperature of 260°C for a duration of 10 seconds, which is consistent with common lead-free (Pb-free) soldering process profiles.

2.2 Electro-Optical Characteristics

Unless otherwise specified, these parameters are measured at a standard ambient temperature of 25°C and a forward current (I_F) of 20 mA. They define the device's performance under normal operating conditions.

• Luminous intensity (I_V):) ranges from a minimum of 45.0 mcd to a typical value of 90.0 mcd. Intensity is measured using a sensor-filter combination approximating the photopic (CIE) human eye response curve. Actual intensity is subject to a binning system (see Section 3).
• Viewing angle (2θ_1/2):130 degrees. This is the full angle at which the luminous intensity drops to half of the value measured on the center axis (0°). Such a wide viewing angle is typical for chip LEDs using a lensless (water-clear) package, providing broad, diffuse illumination.
• Peak emission wavelength (λ_P):611 nm. This is the wavelength at which the spectral power distribution of the emitted light reaches its maximum. It defines the perceived hue of the orange light.
• Dominant Wavelength (λ_d):605 nm. Derived from the CIE chromaticity diagram, this is the single wavelength that best represents the perceived color of the LED output, corresponding to standard orange.
• Spectral Line Half-Width (Δλ):17 nm. This parameter indicates the spectral purity or bandwidth of the emitted light. It is the width of the spectral distribution at half of its maximum power. A value of 17 nm is characteristic of AlInGaP material, providing good color saturation.
• Forward Voltage (V_F):Typical value is 2.40 V, maximum is 2.40 V at I_F=20mA. Minimum value is 2.0 V. This is the voltage drop across the LED when the specified current is conducted.
• Reverse Current (I_R):When a 5V reverse voltage (V_R) hali, kuma ya iya kaiwa 10 μA. Wannan yana nuna yawan zubar da ruwa a yanayin kashewa.

3. Grading System Description

Don tabbatar da daidaiton haske tsakanin nau'ikan samarwa daban-daban, ƙarfin haske na LTST-C281KFKT an raba shi zuwa matakai daban-daban. Kowane mataki yana wakiltar takamaiman kewayon ƙimar ƙarfin da aka auna a daidaitattun sharuɗɗan gwajin na yanzu na 20 mA.

List of gear codes is as follows:

• Gear code P:45.0 mcd (minimum) to 71.0 mcd (maximum)
• Gear Code Q:71.0 mcd to 112.0 mcd
• Gear Code R:112.0 mcd to 180.0 mcd
• Gear code S:180.0 mcd to 280.0 mcd

A tolerance of +/-15% is applied to each intensity bin. This means any individual LED within a specific bin (e.g., bin Q) is guaranteed to have an intensity between 71.0 mcd and 112.0 mcd, but the actual distribution may have a ±15% deviation around the nominal bin range. Designers should select the appropriate bin based on the brightness level required for their application, taking this tolerance into account.

4. Performance Curve Analysis

Ko da yake takaddar ƙayyadaddun bayanai tana ɗaukar takamaiman lanƙwan lanƙwai (misali Hoto 1, Hoto 6), ana iya bayyana halayensu na yau da kullun bisa ga bayanin fasaha.

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

For AlInGaP LEDs such as the LTST-C281KFKT, the I-V relationship is exponential, similar to a standard diode. The temperature coefficient of the forward voltage (V_F) is relatively low compared to some other LED types, but for a given current, it still decreases slightly as the junction temperature increases. The specified 2.4V (typical) V_Fat 20mA is a key parameter for drive circuit design.

4.2 Luminous Intensity vs. Forward Current

Within the normal operating range (up to a DC maximum of 30mA), the light output (luminous intensity) is approximately proportional to the forward current. However, at extremely high currents, efficiency may decrease due to increased thermal effects and reduced efficiency. Operating at a typical 20mA provides a good balance between brightness and lifespan.

4.3 Temperature Characteristics

Like all LEDs, the performance of the LTST-C281KFKT is temperature-dependent. As the junction temperature increases, the luminous intensity typically decreases. The dominant wavelength (λ_d) may also experience a slight red shift (increase in wavelength) with rising temperature, which can lead to subtle changes in perceived color. Proper thermal management in the application is crucial for maintaining consistent optical performance.

4.4 Spectral Distribution

The spectral output is centered at 611 nm (peak) with a half-width of 17 nm. This produces monochromatic orange light with high color purity. The spectrum does not contain the broad white light components commonly found in phosphor-converted white LEDs.

5. Mechanical and Packaging Information

5.1 Package Dimensions

This LED adopts the EIA (Electronic Industries Alliance) standard package outline. Its defining feature is an ultra-thin profile with a height (H) of 0.35 mm. All dimension drawings specify measurements in millimeters, with a standard tolerance of ±0.10 mm unless otherwise noted. The package is "water clear," meaning the encapsulant material is transparent without a diffusing lens, which contributes to achieving a wide viewing angle of 130 degrees.

5.2 Polarity Identification

The datasheet includes a diagram showing the recommended pad layout on the PCB. This layout typically indicates the anode and cathode connections. Correct polarity is crucial for the proper operation of the LED. Applying a reverse voltage exceeding the 5V rating may cause immediate damage.

5.3 Carrier Tape and Reel Packaging

Components are supplied in 8mm wide embossed carrier tape, wound onto 7-inch (178mm) diameter reels. This is the standard packaging for automated SMD assembly. Each reel contains 5000 pieces. The tape has a cover seal to protect components from contamination. The specification states that a maximum of two consecutive component pockets may be empty, and the minimum order quantity for the remainder is 500 pieces. This packaging complies with the ANSI/EIA-481 standard.

6. Soldering and Assembly Guide

6.1 Reflow soldering temperature profile

Provided recommended infrared (IR) reflow soldering temperature profile for lead-free process. Key parameters include:

• Preheat:Heat up to a temperature between 150°C and 200°C.
• Preheating time:Maximum 120 seconds to allow the solder paste to heat evenly and evaporate the solvent.
• Peak temperature:Maximum 260°C.
• Time above liquidus:The maximum time the LED should be exposed to peak temperature is 10 seconds. This profile is designed to comply with JEDEC standards to ensure reliable solder joint formation without damaging the LED package. It is crucial to follow the solder paste manufacturer's recommendations and perform board-specific profiling, as different PCB designs and materials can affect the thermal profile.

6.2 Manual soldering

If manual soldering is necessary, use a soldering iron with a temperature not exceeding 300°C. The contact time for each solder joint should be limited to a maximum of 3 seconds, and each pad should be soldered only once to prevent thermal stress on the LED.

6.3 Storage Conditions

Correct storage is crucial for maintaining solderability and preventing damage caused by moisture during reflow soldering (popcorn effect).

• Sealed packaging:LEDs in the original moisture barrier bag with desiccant should be stored at ≤30°C and ≤90% relative humidity (RH). The recommended shelf life under these conditions is one year.
• Opened package:Once the moisture barrier bag is opened, components should be stored under conditions of ≤30°C and ≤60% RH. It is recommended to complete the infrared reflow soldering process within 672 hours (28 days) after exposure.
• Extended opened storage:For storage exceeding 672 hours, components should be placed in a sealed container with desiccant or a nitrogen desiccator. If stored opened for more than 672 hours, baking at approximately 60°C for at least 20 hours is required before soldering to remove absorbed moisture.

6.4 Cleaning

If post-soldering cleaning is required, only specified alcohol-based solvents may be used. Immersing the LED in ethanol or isopropyl alcohol at room temperature for less than one minute is acceptable. Using unspecified chemical cleaners may damage the LED packaging material.

7. Application Suggestions

7.1 Typical Application Scenarios

This LED is suitable for status indication, backlighting of small icons or symbols, and panel lighting in various consumer and industrial electronic products. For example, power indicator lights on routers/modems, backlighting for buttons on remote controls or appliances, and status lights on computer peripherals. Its slim profile makes it an ideal choice for ultrathin devices with valuable internal space, such as modern smartphones, tablets, and laptops.

7.2 Drive Circuit Design

LED is a current-driven device. To ensure uniform brightness, especially when multiple LEDs are connected in parallel, it is strongly recommended to connect a current-limiting resistor in series with each LED. A simple drive circuit consists of a voltage source (V_CC), series resistor (R_S) and LED. The resistance value can be calculated using Ohm's law: R_S= (V_CC- V_F) / I_F, where V_Fis the forward voltage of the LED (a design margin of 2.4V is used), I_Fis the required operating current (e.g., 20mA). This configuration provides stable current regulation and protects the LED from current spikes.

7.3 Design Considerations

• ESD Protection:AlInGaP LEDs are sensitive to electrostatic discharge (ESD). Handling procedures must include proper ESD precautions: use wrist straps, anti-static mats, and grounded equipment. The LEDs themselves may not have integrated ESD protection, so circuit-level protection (e.g., transient voltage suppression diodes) may be necessary in ESD-prone environments.
• Thermal Management:Although power consumption is low (maximum 75 mW), ensuring adequate heat dissipation through the PCB copper pads is crucial for maintaining long-term reliability and consistent light output, especially under high ambient temperature conditions or when operating near the maximum current.
• Optical Design:The wide viewing angle and water-clear package mean light is emitted diffusely. For applications requiring a more directional beam, an external lens or light guide may be necessary.

8. Technical Comparison and Differentiation

LTST-C281KFKT primarily through its0.35mm Ultra-Thin HeightAchieving differentiation, this is thinner than many standard chip LEDs (e.g., 0603 or 0402 packages, typically 0.55-0.65 mm in height). This is a key advantage for modern portable and wearable electronics. Adoption ofAlInGaP technology, compared to older technologies like GaAsP, offers higher luminous efficiency and better temperature stability for orange/red light. Its compatibility with standardlead-free process infrared reflow solderingandCarrier tape reel packagingcompatibility, aligning it with high-volume, automated manufacturing, providing a cost-effective solution for mass production.

9. Frequently Asked Questions (Based on Technical Parameters)

Q1: Can I drive this LED directly with a 3.3V or 5V logic output?
A: No. You must use a series current-limiting resistor. For example, with a 3.3V supply and a target current of 20mA, the resistor value is approximately (3.3V - 2.4V) / 0.02A = 45 ohms. Direct driving may exceed the maximum current and damage the LED.

Q2: Pepe fafanau o le galu (611nm) ma le galu autu (605nm) e eseese i le a?
A: O le pepe fafanau o le galu o le pito sili ona maualuga moni i luga o le fa'asologa o fua o le malamalama. O le galu autu o se fuainumera fuafuaina i le faasaienisi o lanu, e faaalia ai le lanu iloa e pei o se galu e tasi. Mo lenei LED moli, e latalata uma ia tau, e faamaonia ai le tumu o lanu.

Q3: O le tulaga fa'ailoga o le "Q". O le a le malamalama tonu e mafai ona ou fa'amoemoeina?
A: When measured at 20mA, you can expect the luminous intensity to be between 71.0 mcd and 112.0 mcd. Due to a bin tolerance of +/-15%, the actual value of any individual LED may fall anywhere within that range. For critical brightness matching applications, testing and sorting may be necessary.

Q4: How to understand the "130-degree" viewing angle?
A: This means if you look at the LED from directly above (0°), you see maximum brightness. As you move off-axis, the brightness decreases. At an angle of 65° off-center (130°/2), the brightness will be half of the on-axis value. Light is still visible beyond this angle.

10. Practical Design and Usage Cases

Case: Designing Status Indicator Lights for a Portable Bluetooth Speaker
The designer required a low-power, bright orange LED to indicate the "charging" status. The main PCB of the speaker had thickness constraints, and the LED had to be placed behind a thin plastic diffuser.

Implementation Plan:LTST-C281KFKT was selected for its 0.35 mm height, suitable for mechanical stacking. The drive circuit uses the existing 3.3V system power rail. The series resistor is calculated as 47 ohms (standard value): (3.3V - 2.4V) / 0.02A ≈ 45 ohms, providing approximately 19mA current. The 130° wide viewing angle ensures the charging indicator is visible from various angles of the speaker. The LED comes in tape and reel packaging, facilitating automated assembly for mass production. The designer specified R bin or higher to the supplier to guarantee high brightness visibility even in well-lit rooms.

11. Introduction to Technical Principles

LTST-C281KFKT is based on AlInGaP semiconductor technology. This material is a III-V compound semiconductor. When a forward voltage is applied across the p-n junction, electrons and holes are injected into the active region. Their recombination releases energy in the form of photons (light). The specific composition of aluminum, indium, gallium, and phosphorus in the lattice determines the bandgap energy, which directly dictates the wavelength (color) of the emitted light. For this LED, the bandgap is engineered to produce photons in the orange spectrum (approximately 605-611 nm). The water-clear epoxy encapsulant protects the semiconductor chip, provides mechanical stability, and acts as the primary optical element, shaping the light output pattern.

12. Technology Trends

The trend for indicator LEDs like the LTST-C281KFKT continues towardMiniaturization(Smaller footprint and thinner form factor) development to achieve more stylish product designs.Improve efficiency(More light output per mA of current) is a continuous driving force to reduce power consumption in battery-powered devices. At the same time, attention is also paid toImproving color consistency and stricter binningto meet the application requirements where multiple LEDs must be perfectly matched. Additionally, withAdvanced packaging和Driver ICIntegration in multi-chip modules is an emerging trend for smart lighting applications, but for simple indicator lights, discrete components like this LED remain highly cost-effective and versatile.