Orange SMD LED LTST-C150KFKT Datasheet - EIA Package - 20mA - 90mcd - Technical Documentation

1. Product Overview

LTST-C150KFKT, modern elektronik uygulamalarda güvenilir ve verimli turuncu gösterge aydınlatması gerektiren durumlar için tasarlanmış, yüksek parlaklıklı bir yüzey montaj LED'idir. Gelişmiş AlInGaP yarı iletken çip kullanır; bu çip, turuncu-kırmızı spektrum aralığında yüksek ışık şiddeti ve yüksek verimlilik üretmesiyle bilinir. Bileşen, EIA standartlarına uygun bir paketleme formunda sunulur ve seri üretimde yaygın olarak kullanılan otomatik yüzey montaj sistemleriyle uyumludur. Cihaz, verimli işleme ve işlenme için 7 inç çapında bir makaraya sarılı, 8mm taşıma bandı formatında sağlanır.

Its primary design objectives are to deliver consistent optical performance, compatibility with lead-free soldering processes, and adherence to environmental standards such as RoHS. The "Water Clear" lens material allows the chip's inherent color to be emitted without significant diffusion or color shift, resulting in a saturated orange light output.

2. Detailed Technical Parameters

2.1 Absolute Maximum Ratings

These ratings define the stress limits that may cause permanent damage to the device. Operation at or beyond these limits is not guaranteed. To ensure long-term reliability, such operation should be avoided.

• Power Dissipation:75 mW. This is the maximum total power that the package can dissipate when the ambient temperature is 25°C. Exceeding this limit risks overheating and damaging the semiconductor junction.
• DC forward current:30 mA. The maximum continuous forward current that can be applied.
• Peak Forward Current:80 mA. This current is only permitted under pulse conditions to handle brief current surges.
• Derating Factor:For every 1°C increase in ambient temperature, the maximum allowable DC forward current must be reduced by 0.4 mA to prevent thermal overstress.
• Reverse Voltage:5 V. Applying a reverse voltage exceeding this value may lead to breakdown and failure.
• Operating and Storage Temperature Range:-55°C to +85°C. The device can operate and be stored within this full range.
• Soldering Temperature Tolerance:The device can withstand 260°C wave soldering or infrared reflow soldering for 5 seconds, and 215°C vapor phase soldering for 3 minutes.

2.2 Electrical and Optical Characteristics

These are typical performance parameters measured under standard test conditions of Ta=25°C and IF=20mA.

• Luminous Intensity:45.0 mcd, typical 90.0 mcd. This is the light output measured in millicandelas. The value is measured using a sensor filtered to match the spectral response curve of the human eye.
• Viewing Angle:Typical 130°. This wide viewing angle indicates light is emitted in a broad, Lambertian pattern, suitable for applications requiring wide-range visibility.
• Peak Emission Wavelength:Typical value 611 nm. The specific wavelength at which the spectral output is strongest.
• Dominant Wavelength:Typical value 605 nm. This is the single wavelength perceived by the human eye that defines the LED color, derived from the CIE chromaticity diagram.
• Spectral line half-width:Typical value 17 nm. This indicates spectral purity; a narrower width means the output is closer to monochromatic.
• Forward voltage:At IF=20mA, min 2.0V, typ 2.4V. The voltage drop across the LED when operating. This is crucial for designing current limiting circuits.
• Reverse Current:At VR=5V, max 10 µA. The small leakage current when the device is reverse biased.
• Capacitance:Typical value 40 pF at VF=0V, f=1MHz. Junction capacitance, may be relevant for high-speed switching applications.

3. Binning System Description

The luminous intensity of LEDs may vary between batches. To ensure consistency for end users, products are sorted into different "bins" based on measured performance. For LTST-C150KFKT, the primary binning criterion is luminous intensity at 20mA.

• Bin Code P:45.0 - 71.0 mcd
• Bin Code Q:71.0 - 112.0 mcd
• Bin Code R:112.0 - 180.0 mcdBin Code S:180.0 - 280.0 mcd

A tolerance of +/-15% is applied to each brightness bin. When designing systems with strict requirements for brightness uniformity, specifying a single bin code or understanding the bin range is crucial to avoid visible brightness differences.

4. Performance Curve Analysis

Although specific charts are referenced in the datasheet, their implied characteristics are standard for AlInGaP LEDs and are critical for design.

4.1 Forward Current vs. Forward Voltage Characteristic Curve

This relationship is exponential. A small increase in voltage beyond the turn-on threshold leads to a large increase in current. This is why an LED must be driven by a current-limited source, not a constant voltage source, to prevent thermal runaway and damage.

4.2 Luminous Intensity vs. Forward Current Relationship

Within the operating range, light output is typically proportional to the forward current. However, efficiency usually peaks at currents below the maximum rated value and decreases at higher currents due to increased heat.

4.3 Temperature Dependence

Luminous intensity and forward voltage exhibit temperature dependence. As junction temperature increases:

• Luminous intensity decreases:Output may decrease significantly, a factor that must be considered in thermal management.
• Forward voltage decreases:VF has a negative temperature coefficient. If the ambient temperature changes significantly, this will affect the current in a simple resistor current-limiting circuit.

4.4 Spectral Distribution

The spectral output curve will be centered at a peak wavelength of 611 nm. The half-width of 17 nm indicates a relatively narrow spectrum, which is characteristic of direct bandgap semiconductors such as AlInGaP, resulting in a pure orange light.

5. Mechanical and Packaging Information

The device conforms to the EIA surface mount package outline standard. Key dimension specifications include:

• 所有主要尺寸均以毫米为单位。Unless otherwise specified, the standard tolerance is ±0.10 mm.

The datasheet includes detailed dimensional drawings of the LED body, which are crucial for creating the PCB pad pattern. A recommended pad layout is also provided to ensure reliable solder joint formation and proper alignment during the reflow process. Polarity is indicated by the cathode mark on the device, typically a notch, a green line, or other visual markers on one side of the package.

6. Soldering and Assembly Guide

6.1 Reflow Soldering Temperature Profile

Specification provides two recommended infrared reflow soldering temperature profiles:

1. Conventional process:Standard curve suitable for tin-lead solder.
2. Lead-free process:A profile optimized for lead-free solder pastes such as SAC. This profile typically features a higher peak temperature to accommodate the higher melting point of lead-free alloys. The time above liquidus and the heating rate are critical to prevent thermal shock and ensure the formation of good solder joints without damaging the LED's epoxy encapsulation.

6.2 Storage Conditions

LEDs are moisture-sensitive devices. Prolonged exposure to ambient humidity may lead to the "popcorn" phenomenon during high-temperature reflow soldering, caused by the rapid vaporization of absorbed moisture.

• Recommended storage conditions:Temperature not exceeding 30°C, relative humidity not exceeding 70%.
• Bag opening time:If removed from the original moisture barrier bag, the LED should be reflow soldered within one week.
• Long-term storage/baking:For storage outside the original packaging for more than one week, LEDs should be stored in a sealed container with desiccant or in a nitrogen environment. LEDs stored in this manner for more than one week should be baked at approximately 60°C for at least 24 hours to remove moisture prior to soldering.

6.3 Cleaning

Ya kamata a yi amfani da kawai mai tsaftacewa da aka kayyade. Sinadarai da ba a kayyade ba na iya lalata ruwan tabarau na epoxy ko kunshe. Idan ana buƙatar tsaftacewa bayan walda, ana ba da shawarar nutsar da cikin ethanol ko isopropyl alcohol a yanayin zafi na yau da kullun har tsawon minti ɗaya.

7. Packaging and Ordering Information

Ana samar da samfurin a cikin marufi na ƙa'idodin masana'antu wanda ya dace da haɗawa ta atomatik:

• Carrier Tape and Reel:8mm wide embossed carrier tape.
• Reel dimensions:Diameter 7 inches.
• Quantity per roll:3000 pieces.
• Minimum order quantity:Minimum order quantity starts from 500 pieces remaining.
• Packaging Standard:Compliant with ANSI/EIA-481-1-A-1994 specification. Empty positions in the carrier tape are sealed with cover tape.

Model LTST-C150KFKT follows the typical manufacturer coding system, where elements may indicate series, color, brightness bin, lens type, and packaging.

8. Application Recommendations

8.1 Typical Application Scenarios

This LED is suitable for a wide range of applications requiring orange status indication, backlighting, or decorative lighting, including:

• Consumer electronics.
• Industrial control panels and instrumentation.
• Car interior lighting.
• Signage and decorative lighting.
• General indicator lights on PCB.

Important note:The datasheet clearly states that this LED is suitable for "general electronic equipment". For applications requiring extremely high reliability, where failure could endanger life or health, consult the manufacturer before design.

8.2 Design Considerations and Circuit Configuration

Driving Method:LED is a current-driven device. The most critical design rule is to control the forward current.

• Recommended Circuit:Use a series current-limiting resistor for each LED. This is crucial when connecting multiple LEDs in parallel, as it compensates for the natural differences in the forward voltage (VF) of individual LEDs. Without individual resistors, an LED with a slightly lower VF will draw a disproportionate amount of current, leading to uneven brightness and potential overcurrent failure.
• Not Recommended Circuit:It is discouraged to directly connect multiple LEDs in parallel and share a single current-limiting resistor due to the risk of current imbalance mentioned above.

The value of the series resistor is calculated using Ohm's Law: R = / I_desired. For conservative design, always use the typical or maximum VF value from the datasheet.

8.3 Electrostatic Discharge Protection

LEDs are sensitive to electrostatic discharge. ESD can cause latent or catastrophic damage, manifested as high reverse leakage current, low forward voltage, or failure to illuminate at low currents.

Preventive measures include:

• Use conductive wrist straps or anti-static gloves during operation.
• Ensure all workstations, equipment, and storage racks are properly grounded.
• Use an ionizer to neutralize static charges that may accumulate on plastic lenses.

To test for potential ESD damage, check if the LED lights up and measure its VF at a low test current. Abnormal readings indicate possible damage.

9. Technical Comparison and Differentiation

The key differentiating advantages of the LTST-C150KFKT stem from its material system and package design:

• AlInGaP chip technology:Compared to older technologies such as standard GaAsP, AlInGaP offers significantly higher luminous efficiency and brightness, better temperature stability, and a longer service life. This makes it superior for applications that require high visibility and reliability.
• Water clear lens:Compared to scattering or colored lenses, it provides more saturated and vivid colors, as the latter scatter light and may reduce color purity. This is ideal for applications where color definition is important.
• Lead-Free and RoHS Compliance:Complies with modern environmental regulations, which are mandatory requirements for most electronic products sold today.
• Wide Viewing Angle:Provides excellent off-axis visibility, which is beneficial for panel indicators that need to be viewed from different angles.

10. Frequently Asked Questions

10.1 What is the difference between peak wavelength and dominant wavelength?

Peak wavelengthis the physical wavelength at which an LED emits the most optical power, measured directly from the spectrum.Dominant wavelengthIt is a calculated value based on human color perception, best representing the single color we see. For monochromatic LEDs like this orange one, they are often very close, but λd is the more relevant parameter for color specification in design.

10.2 Why is a 20mA test current used?

20mA has historically been the standard drive current for many small-signal LEDs, offering a good balance between brightness, efficiency, and power consumption. It serves as a common reference point for comparing different LED models. Your application can use a different current, but all performance parameters will change accordingly, and you must stay within the Absolute Maximum Ratings.

10.3 How to select the correct brightness bin?

Zaɓi ƙimar haske bisa ga buƙatun haske na aikace-aikace da ƙimar daidaiton haske. Don alamar nuni guda ɗaya, kowane ƙimar haske na iya isa. Don tsararrun da duk LED ɗin dole su yi kama da haske iri ɗaya, ya kamata ka keɓance ƙimar haske guda ɗaya mai matsi, kuma mai yiyuwa ne a yi amfani da watsa haske na gani don ɓoye ƙananan bambance-bambancen da suka rage.

10.4 Can this LED be driven directly by a 3.3V or 5V microcontroller pin?

Ba iya tuƙa kai tsaye.Microcontroller GPIO pins are voltage sources, not current sources, and typically cannot provide a stable 20mA current while maintaining their output voltage. More importantly, they cannot provide protection against the LED's negative temperature coefficient. YouDoleAs described in Section 8.2, use a series current-limiting resistor. For a 3.3V power supply and a target current of 20mA, the resistor value is approximately / 0.02A = 45 ohms. A standard 47-ohm resistor would be a suitable choice.

11. Practical Design and Application Cases

Scenario:Design a status indicator panel for industrial equipment that requires three bright, uniform orange LEDs to indicate the "system operational" status.

1. Component Selection:LTST-C150KFKT was selected for its high brightness, orange color, and SMD package suitable for automated assembly.
2. Circuit Design:The system power rail is 5V. To ensure uniform brightness, three identical drive circuits are used, one for each LED. Using a typical VF of 2.4V and a design current of 20mA, calculate the series resistor value: R = (5V - 2.4V) / 0.02A = 130 ohms. Select the nearest standard value of 130 or 120 ohms. The resistor's power rating is (5V - 2.4V) * 0.02A = 0.052W, so a standard 1/8W resistor is more than sufficient.
3. PCB Layout:Create PCB pad geometries using the manufacturer's recommended pad dimensions from the datasheet. Maintain sufficient spacing between LEDs for heat dissipation.
4. Thermal considerations:The panel is located inside the housing. To mitigate the reduction in light output caused by temperature rise, small thermal vias are placed near the LED pads to conduct heat to other PCB layers, and the housing is ventilated.
5. Procurement:Doni a kula kuma a yi amfani da shi a cikin samarwa, an ƙayyade "Rarrabawa Code S" don duk 3,000 na takamaiman guntun da ake buƙata.

12. Working Principle

Hasken fitowa a cikin LTST-C150KFKT ya dogara ne akan hasken lantarki a cikin mahaɗin p-n semiconductor da aka yi da kayan AlInGaP. Lokacin da ake amfani da ƙarfin lantarki mai kyau, electrons daga yankin n-type da ramuka daga yankin p-type ana shigar da su cikin yankin haɗin gwiwa. Lokacin da waɗannan masu ɗaukar kaya suka haɗu a cikin yankin aiki na semiconductor, suna sakin makamashi. A cikin kayan kai tsaye kamar AlInGaP, wannan makamashi yana fitarwa da farko a cikin nau'in photons. Takamaiman tsawon zango na hasken da ake fitarwa yana ƙayyade ta hanyar makamashin tazarar band na kayan semiconductor, wanda aka tsara yayin girma crystal zuwa kusan 2.03 eV, yana dacewa da hashen orange mai kusan 611 nm. Kayan rufi na epoxy "Ruwa mai tsabta" yana kare guntu, yana ba da kwanciyar hankali na injiniya, kuma yana aiki azaman ruwan tabarau don siffanta fitowar hasken.

13. Technical Trends

The development of LED technology continues to focus on several key areas related to components such as LTST-C150KFKT:

• Improving Efficiency:Ongoing materials science research aims to reduce non-radiative recombination and improve the light extraction efficiency of chips, resulting in brighter LEDs at the same current or the same brightness at lower power.
• Improving Color Consistency and Binning:Advances in epitaxial growth and manufacturing process control have led to tighter parameter distributions, reducing the need for extensive binning and providing more consistent production performance.
• Miniaturization:The drive for smaller electronic devices is pushing LED package sizes to continuously shrink while maintaining or improving optical output.
• Higher Reliability and Lifespan:Improvements in packaging materials and die-attach technology enhance resistance to thermal cycling, humidity, and other environmental stresses, extending the service life.
• Integration:The trend of integrating multiple LED chips, control circuits, and even drivers into a single package to simplify end-user design and reduce PCB space.

Components like the LTST-C150KFKT represent a mature, optimized node in this evolution, providing a reliable and high-performance solution for standard indicator applications.