LTST-C193KGKT-2A SMD LED Datasheet - Size 1.6x0.8x0.35mm - Voltage 1.6-2.2V - Green - Technical Documentation

1. Product Overview

LTST-C193KGKT-2A is a surface-mount device (SMD) chip LED designed specifically for modern space-constrained electronic applications. Its primary function is to provide a reliable and bright green light source. The core advantage of this component lies in its ultra-thin profile of only 0.35 mm, making it highly suitable for applications where vertical space is extremely valuable, such as ultra-thin displays, mobile devices, and wearable technology. It utilizes AlInGaP (aluminum indium gallium phosphide) semiconductor material for the light-emitting region, a material renowned for producing high-efficiency light in the green to amber spectral range. The device is supplied on industry-standard 8 mm carrier tape wound on 7-inch reels, ensuring compatibility with high-speed automated pick-and-place assembly equipment. It is classified as a green product and complies with the RoHS (Restriction of Hazardous Substances) directive.

2. In-depth Interpretation of Technical Parameters

2.1 Absolute Maximum Ratings

These ratings define the stress limits that may cause permanent damage to the device. Operation under conditions at or beyond these limits is not guaranteed.

• Power Dissipation (Pd):75 mW. This is the maximum power that the LED package can dissipate as heat when the ambient temperature (Ta) is 25°C. Exceeding this value may cause overheating and shorten the service life.
• DC Forward Current (IF):30 mA. The maximum continuous current that can be applied to the LED.
• Peak Forward Current:80 mA, but only under pulse conditions (1/10 duty cycle, 0.1ms pulse width). This allows for higher brightness in a short time without causing thermal damage.
• Derating:For every 1°C increase in ambient temperature above 25°C, the maximum forward current must be linearly reduced by 0.4 mA. This is crucial for thermal management in high-temperature environments.
• Reverse Voltage (VR):5 V. Applying a reverse voltage higher than this value may cause immediate catastrophic failure of the LED junction.
• Operating and Storage Temperature Range:-55°C to +85°C. The device is rated for operation and storage within this broad industrial temperature range.
• Soldering Temperature Tolerance:The LED can withstand up to 5 seconds of wave or infrared reflow soldering at 260°C, and up to 3 minutes of vapor phase soldering at 215°C. This defines its compatibility with common PCB assembly processes.

2.2 Electrical and Optical Characteristics

These are typical performance parameters measured at Ta=25°C and a standard test current (IF) of 2mA (unless otherwise specified).

• Luminous Intensity (Iv):The range is from a minimum of 1.80 mcd to a maximum of 11.2 mcd. The measured value for a specific unit depends on its assigned bin code (see Section 3). A filter approximating the photopic response curve of the human eye is used for intensity measurements.
• Viewing Angle (2θ1/2):130 degrees. This is a very wide viewing angle, meaning the emitted light is dispersed over a broad area rather than a narrow beam. This angle is defined as the point where the luminous intensity drops to half of its axial (0-degree) value.
• Peak Emission Wavelength (λP):574 nm. This is the specific wavelength at which the LED emits the most optical power.
• Dominant Wavelength (λd):The range is from 564.5 nm to 573.5 nm. This is the single wavelength perceived by the human eye that defines the color (green in this case). It is derived from the full spectrum output and the CIE chromaticity diagram. Specific bins are defined within this range.
• Spectral Line Half-Width (Δλ):15 nm. This indicates the spectral purity or bandwidth of the emitted light. A smaller value indicates better monochromaticity (color purity) of the light source.
• Forward Voltage (VF):At IF=2mA, the range is from 1.60 V to 2.20 V. This is the voltage drop across the LED when it is conducting current. It is a key parameter for designing current-limiting circuits.
• Reverse Current (IR):At VR=5V, maximum 10 μA. This is the small leakage current that flows when the LED is reverse-biased within its maximum ratings.
• Capacitance (C):Measured 40 pF at 0V bias and 1 MHz. This parasitic capacitance may be relevant in high-frequency switching applications.
• Electrostatic Discharge (ESD) Threshold (HBM):1000 V (Human Body Model). This indicates a medium level of ESD sensitivity. Proper ESD handling procedures must be followed to prevent latent or immediate damage.

3. Grading System Description

To ensure consistency in mass production, LEDs are sorted into different performance bins based on key parameters. This allows designers to select components that meet the brightness and color requirements of specific applications.

3.1 Luminous Intensity Binning

Based on the luminous intensity measured at 2mA, the units are divided into four bins (G, H, J, K). Each bin has a minimum and maximum value, with a tolerance of +/-15% for each intensity bin.

• Bin G:1.80 - 2.80 mcd
• Gear H:2.80 - 4.50 mcd
• Gear J:4.50 - 7.10 mcd
• Gear K:7.10 - 11.20 mcd

3.2 Dominant Wavelength Binning

Units are also sorted into three groups (B, C, D) based on their dominant wavelength, which defines the precise hue of green. The tolerance for each bin is +/- 1 nm.

• Gear B:564.5 - 567.5 nm
• Gear C:567.5 - 570.5 nm
• Bin D:570.5 - 573.5 nm

The complete part number (e.g., LTST-C193KGKT-2A) includes these bin codes for precise selection. "K" indicates the intensity bin, and the subsequent letter (implied in the datasheet example) indicates the wavelength bin.

4. Performance Curve Analysis

Although the datasheet references specific graphical curves (Figure 1, Figure 6), its typical behavior can be described technically.

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

AlInGaP LEDs exhibit a characteristic I-V curve, with a forward voltage (VF) in the range of 1.6-2.2V at low current (2mA). As the forward current increases, VF increases logarithmically. This nonlinear relationship is why LEDs must be driven by a constant current source or with a series current-limiting resistor, and cannot be driven by a constant voltage source.

4.2 Luminous Intensity vs. Forward Current

In most of the operating range, the light output (luminous intensity) is approximately proportional to the forward current. However, at very high currents, efficiency decreases due to increased heat generation (efficiency droop effect). The rated DC current of 30mA defines a safe operating point for maintaining efficiency and lifespan.

4.3 Temperature Characteristics

LED's forward voltage (VF) has a negative temperature coefficient, meaning it decreases as the junction temperature rises. Conversely, luminous intensity and dominant wavelength also change with temperature; typically, intensity decreases, and the wavelength may increase slightly (red shift). The derating specification (0.4 mA/°C) is a direct result of managing these thermal effects.

5. Mechanical and Packaging Information

5.1 Package Dimensions

This LED adopts the EIA standard chip package outline. Key dimensions include a length of 1.6mm, a width of 0.8mm, and a critical height of 0.35mm. Unless otherwise specified, all dimensional tolerances are typically ±0.10mm. The package utilizes a water-clear lens, which does not alter the color of the underlying AlInGaP chip, allowing the intrinsic green light to pass through.

The datasheet includes the recommended PCB design solder pad layout (land pattern). Adhering to this layout is crucial for achieving reliable solder joints and proper alignment during the reflow soldering process. The LED itself has anode and cathode markings (typically a notch, bevel, or dot near the cathode). Care must be taken to ensure correct polarity during assembly, as reverse connection will cause the device to not function and may damage it if the reverse voltage rating is exceeded.

5.3 Carrier Tape and Reel Packaging

Components are supplied in 8mm wide embossed carrier tape, wound on 7-inch (178mm) diameter reels. Each reel contains 5000 pieces. The packaging conforms to the ANSI/EIA 481-1-A-1994 standard, ensuring compatibility with automatic feeders. The carrier tape is covered to protect components from contamination. The specification allows for a maximum of two consecutive missing components, with a minimum packaging quantity of 500 pieces for the remaining reel.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Temperature Profile

The datasheet provides recommended infrared (IR) reflow soldering temperature profiles for both conventional (SnPb) and lead-free (SnAgCu) soldering processes. Key parameters include:

Preheating:

• Gradually increase the temperature to the wetting temperature (e.g., 120-150°C) to activate the flux and minimize thermal shock.Peak Temperature:
• It must not exceed 260°C. The time above the liquidus (approximately 217°C for lead-free solder) and the time at peak temperature must be controlled to prevent damage to the LED's plastic package and internal wire bonds. It is recommended not to exceed 5 seconds at 260°C.Cooling rate:
• A controlled cooling phase is also important for solder joint reliability.6.2 Wave Soldering and Manual Soldering

For wave soldering, preheating is recommended up to 100°C for a maximum of 60 seconds, and the solder wave up to 260°C for a maximum of 10 seconds. For manual repair using a soldering iron, the tip temperature should not exceed 300°C, and the contact time per solder joint should be limited to within 3 seconds, and only once, to prevent excessive heat transfer.

6.3 Cleaning

If cleaning is required after soldering, only specified alcohol-based solvents, such as ethanol or isopropanol, should be used. LEDs should be immersed at room temperature for less than one minute. Unspecified chemical cleaners may damage the epoxy lens or packaging material.

6.4 Storage and Handling

LEDs should be stored in an environment not exceeding 30°C and 70% relative humidity. Once removed from the original moisture barrier bag, the components should be reflow soldered within 672 hours (28 days) to avoid moisture absorption, which can lead to "popcorn" phenomenon during reflow. For storage outside the original bag for longer periods, they must be kept in a sealed container with desiccant or in a nitrogen environment. If stored for more than 672 hours, baking at 60°C for at least 24 hours is required before assembly to remove moisture.

7. Shawarwarin Aikace-aikace

7.1 Typical Application Scenarios

This ultra-thin, bright green LED is ideal for:

Status indicator:

• Power, connection, or mode indicators in consumer electronics (smartphones, tablets, laptops, wearables).Backlighting:
• Edge lighting for ultra-thin display panels or keyboard illumination.Automotive interior lighting:
• Dashboard indicator lights, switch backlighting (in space-constrained areas).Industrial control panels:
• Status and fault indicator lights on control units and human-machine interfaces (HMI).7.2 Design Considerations

Current drive:

• LED is a current-driven device. To ensure uniform brightness when multiple LEDs are used in parallel, an independent current-limiting resistor must be connected in series with each LED (Circuit Model A). It is not recommended to directly connect LEDs in parallel (Circuit Model B), as differences in their forward voltage (VF) will cause uneven current distribution, leading to inconsistent brightness.Thermal Management:
• Even at lower power dissipation, proper PCB layout for heat dissipation is important, especially when operating near maximum ratings or at high ambient temperatures. Follow the current derating curve.ESD Protection:
• If the LED is in an exposed location (e.g., a front panel indicator), implement ESD protection measures in the circuit. Always follow ESD-safe handling procedures during assembly: use grounded wrist straps, anti-static mats, and properly grounded equipment.8. Technical Comparison and Differentiation

The key differentiator of the LTST-C193KGKT-2A is its

0.35mm height和AlInGaP technologyCompared to traditional standard GaP (gallium phosphide) green LED technology, AlInGaP offers significantly higher luminous efficiency, resulting in brighter output at the same drive current. The ultra-thin profile is a key advantage over many standard chip LEDs (typically 0.6 mm or higher), enabling its application in the design of next-generation ultra-thin devices. Its compatibility with lead-free, high-temperature reflow soldering processes also makes it suitable for modern, RoHS-compliant production lines.9. Frequently Asked Questions (Based on Technical Specifications)

Q1: Can I drive this LED directly with a 3.3V or 5V logic supply?

A: A'a. Dole ne a yi amfani da resistor a jere don iyakance ƙarfin lantarki. Misali, idan aka yi amfani da wutar lantarki na 3.3V, tare da VF na yau da kullun na 1.9V a 2mA, ƙimar resistor da ake buƙata ita ce R = (3.3V - 1.9V) / 0.002A = 700 ohms. Koyaushe yi lissafi bisa mafi girman VF, don tabbatar da cewa ƙarfin lantarki bai wuce abin da ake so ba.
Q2: Me ya sa kewayon ƙarfin haske ya yi fadi haka (1.8 zuwa 11.2 mcd)?

A: Wannan shine kewayon rarraba samarwa gabaɗaya. Tsarin rarrabuwa (G, H, J, K) yana ba ku damar zaɓar takamaiman, ƙuntataccen kewayon haske don aikace-aikacenku, don tabbatar da daidaito a cikin duk sassan samfurin.
Q3: Is this LED suitable for outdoor use?

A: The operating temperature range (-55°C to +85°C) supports many outdoor environments. However, the plastic package may be susceptible to UV aging and moisture ingress over extended periods. For demanding outdoor applications, specially certified outdoor package LEDs should be considered.
Q4: What happens if I exceed the 5V reverse voltage?

A: LED junction likely experiences avalanche breakdown, leading to immediate and permanent failure (open or short circuit). Ensure circuit design prevents reverse bias from exceeding this rated value.
10. Practical Design Case

Scene:

Design a status indicator light for a battery-powered IoT sensor module. The indicator must be very small, low-power, and clearly visible. A green LED is selected to indicate the "active/normal" status.Implementation Plan:

Component Selection:
1. LTST-C193KGKT-2A is chosen for its 0.35mm height and good brightness at low current.Circuit Design:
2. This module uses a 3.0V coin cell battery. To save power, a drive current of 2mA is selected. A conservative design is adopted, using a maximum VF of 2.20V: R = (3.0V - 2.20V) / 0.002A = 400 ohms. A standard 390-ohm resistor is used.PCB Layout:
3. Use the pad dimensions recommended in the datasheet. The LED is placed near the edge of the board for visibility. Avoid placing a large area of ground copper directly under the LED to prevent solder wicking issues during reflow soldering.Results:
4. This indicator provides sufficient brightness with minimal power consumption (approximately 6mW total for LED and resistor), and its ultra-thin package is suitable for the device's slim housing.11. Introduction to Principles

The light emission in an AlInGaP LED is based on the phenomenon of electroluminescence in a semiconductor p-n junction. When a forward voltage is applied, electrons from the n-type region and holes from the p-type region are injected into the active region (quantum well). When an electron recombines with a hole, energy is released in the form of a photon. The specific wavelength (color) of this photon is determined by the bandgap energy of the AlInGaP alloy composition used in the active region. A wider bandgap produces light of shorter wavelength (bluer); the specific alloy of this LED is designed to produce green light with a peak around 574 nm. The chip is encapsulated in a water-clear epoxy resin lens, providing mechanical protection and helping to shape the light output into a wide viewing angle of 130 degrees.

12. Development Trends

The development trend of chip LEDs for consumer and industrial electronics continues towards:

1. Improving efficiency (lm/W):
Continuous improvements in the materials science of AlInGaP and InGaN (for blue/white light) technologies drive more light output per unit of electrical energy input, reducing power consumption and heat generation.2. Miniaturization:
The pursuit of thinner and smaller devices demands LEDs with continuously decreasing footprint (XY dimensions) and a critical height (Z dimension). This LED's 0.35mm height represents this trend.3. Improved Color Consistency and Binning:
Tighter wavelength and intensity binning tolerances are becoming standard, enabling a more uniform visual appearance in applications using multiple LEDs.4. Enhanced Reliability:
Improved packaging materials (epoxy, silicone) to withstand higher temperature reflow profiles (for lead-free assembly) and harsher environmental conditions.5. Integration:
Although discrete LEDs remain vital, there is also a trend toward integrated LED modules that incorporate built-in drivers, controllers, and multiple colors in a single package for smart lighting applications.While discrete LEDs remain vital, there is a parallel trend toward integrated LED modules with built-in drivers, controllers, and multiple colors in a single package for smart lighting applications.