LTST-C193KRKT-2A SMD LED Datasheet - 0.35mm Ultra-Thin Height - 1.6-2.2V Forward Voltage - Red Light - 75mW Power - Technical Documentation

1. Product Overview

This document provides the complete technical specifications for the LTST-C193KRKT-2A, a high-performance surface-mount chip LED designed for modern electronic applications requiring extremely low component height and reliable performance. The device utilizes advanced AlInGaP (Aluminum Indium Gallium Phosphide) semiconductor technology and is an ultra-thin LED that emits bright red light. Its primary design goal is to enable its integration into space-constrained assemblies without sacrificing optical performance or manufacturability.

The core advantage of this component includes its extremely low profile height of only 0.35mm, which is a critical parameter for slim consumer electronics, displays, and indicator light applications. It is meticulously designed to be compatible with standard automated SMT production lines and high-volume reflow soldering processes, including infrared (IR) and vapor phase soldering methods. This product is classified as a green product, compliant with the RoHS (Restriction of Hazardous Substances) directive, making it suitable for environmentally conscious designs and the global market.

1.1 Key Features and Target Market

The LTST-C193KRKT-2A possesses several key features that define its application areas. The use of an AlInGaP chip is central to its performance, offering higher luminous efficiency and better temperature stability compared to traditional red LED materials. Its package conforms to the EIA (Electronic Industries Alliance) standard, ensuring broad compatibility with industry design libraries and assembly equipment.

Kasuwar da aka yi niyya ga wannan LED ta ƙunshi na'urorin lantarki masu yawa. Manyan yankunan aikace-aikacen sa sun haɗa da na'urori masu sarrafa kansa na ofis (firinta, na'urorin sikan, na'urorin kwafi), na'urorin sadarwa (na'urorin hanyar sadarwa, modem, masu sauya hanyoyin sadarwa), da kayan amfanin gida waɗanda ke buƙatar nuna yanayi, hasken maɓalli, ko hasken aiki. Siffar sa na sirara sosai yana sa shi ya zama mai jan hankali musamman a cikin na'urori masu ɗaukar hoto, gefuna masu kunkuntar allo da talabijin, da kuma kowane aikace-aikace inda tsayin Z-axis ke zama ƙayyadaddun ƙira. Haɗin kai na na'urar tare da haɗawa ta atomatik da haɗaɗɗen warkewa yana sa ya zama zaɓi mai kyau na samarwa mai yawa da ƙimar farashi.

2. In-depth Technical Parameter Analysis

A thorough understanding of electrical, optical, and thermal parameters is crucial for reliable circuit design and system integration. Unless otherwise specified, all specifications are defined at an ambient temperature (Ta) of 25°C.

2.1 Absolute Maximum Ratings

Absolute Maximum Ratings define the stress limits that may cause permanent damage to the device. These are not operating conditions.

• Power Dissipation (Pd):75 mW. This is the maximum power that the LED package can dissipate as heat. Exceeding this limit may cause thermal damage to the semiconductor junction and the epoxy lens.
• DC Forward Current (IF):30 mA. The maximum continuous forward current that can be applied. For pulsed operation, a peak forward current of up to 80 mA is permitted under specific conditions (1/10 duty cycle, 0.1ms pulse width).
• Forward Current Derating:Linear derating of 0.4 mA/°C starting from 25°C. This is a key parameter for thermal management. When the ambient temperature exceeds 25°C, the maximum allowable continuous current must be reduced. For example, at 50°C, the maximum current is 30 mA - [0.4 mA/°C * (50-25)°C] = 20 mA.
• Reverse Voltage (VR):5 V. Applying a reverse bias exceeding this value may cause junction breakdown.
• Operating and Storage Temperature Range:-55°C to +85°C. This wide range ensures reliability in harsh environments.
• Solder Temperature Tolerance:The device can withstand 260°C wave soldering for 5 seconds, 260°C infrared reflow soldering for 5 seconds, and 215°C vapor phase reflow soldering for 3 minutes. These parameters are crucial for defining the assembly process window.

2.2 Electrical and Optical Characteristics

These parameters define the typical performance of the LED under normal operating conditions.

• Luminous Intensity (Iv):At a test current (IF) of 2 mA, the range is from a minimum of 1.80 mcd to a maximum of 11.2 mcd. The intensity of a specific unit is determined by its binning code (see Section 3). Measurement is performed using a sensor filtered to approximate the CIE photopic response curve.
• Viewing Angle (2θ1/2):130 degrees. This is the full angle at which the luminous intensity drops to half of its value on the center axis (0 degrees). Such a wide viewing angle is suitable for applications requiring broad, diffuse illumination rather than a focused beam.
• Peak Wavelength (λP):639 nm. This is the wavelength at which the spectral power output reaches its maximum. It defines the perceived hue of the red light.
• Dominant Wavelength (λd):629 nm. Derived from the CIE chromaticity diagram, this is the single wavelength that best represents the color perceived by the human eye. For red AlInGaP LEDs, it is typically slightly shorter than the peak wavelength.
• Spectral line half-width (Δλ):20 nm. This indicates the spectral purity or bandwidth of the emitted light. A smaller value means better monochromaticity of the light source.
• Forward voltage (VF):At IF = 2 mA, it is 1.60 V to 2.20 V. This is the voltage drop across the LED during operation. It is crucial for designing current-limiting circuits. This variation stems from normal semiconductor manufacturing tolerances.
• Reverse Current (IR):At VR = 5 V, maximum is 10 µA. This is the small leakage current that flows when the device is reverse-biased within its maximum ratings.
• Capacitance (C):At VF = 0V, f = 1 MHz, the typical value is 40 pF. This parasitic capacitance may be relevant in high-frequency switching applications.
• ESD Threshold (HBM):1000 V. This Human Body Model rating indicates the LED's sensitivity to electrostatic discharge. It is classified as moderately sensitive; proper ESD handling procedures must be followed.

3. Explanation of the Grading System

To manage natural variations in semiconductor manufacturing, LEDs are binned according to performance. The LTST-C193KRKT-2A primarily uses a binning system for luminous intensity.

Intensity is measured under standard test conditions at IF = 2 mA. Units are sorted into the following bins:

• G bin:1.80 mcd (minimum) to 2.80 mcd (maximum)
• H bin:2.80 mcd to 4.50 mcd
• J grade:4.50 mcd to 7.10 mcd
• K bin:7.10 mcd to 11.20 mcd

A +/-15% tolerance is applied to the limits of each bin. This binning allows designers to select LEDs with a guaranteed minimum brightness for their application, ensuring consistency in the final product's appearance, especially when multiple LEDs are used side-by-side. For critical color matching applications, it is recommended to consult the manufacturer for specific chromaticity binning information, as this datasheet primarily details intensity binning.

4. Performance Curve Analysis

Although the datasheet provides tabular data, understanding the relationship between parameters through characteristic curves is crucial for robust design.

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

The relationship between forward current (IF) and forward voltage (VF) is nonlinear and exponential, which is a typical characteristic of diodes. The VF range of 1.6V-2.2V specified at 2mA in the datasheet provides a key operating point. Designers must note that for a given current, VF decreases as temperature increases, which, if not properly considered, may affect the current drawn in a simple resistor current-limiting circuit.

4.2 Luminous Intensity vs. Forward Current

A cikin kewayon aiki na yau da kullun, fitowar haske (ƙarfin haske) yana kusan daidai da ƙarfin kwarara mai zuwa. Duk da haka, inganci (lumens kowace watt) na iya kaiwa kololuwa a wani ƙimar kwarara, sannan ya ragu saboda tasirin zafi da na lantarki. Yin aiki a ƙarashin kwararar DC da aka ba da shawarar ko ƙasa da shi yana tabbatar da inganci da rayuwa mafi kyau.

4.3 Temperature Dependence

Ayyukan LED yana shafar yanayin zafi sosai. Manyan tasirin sun haɗa da:

• Luminous Intensity:Output decreases as junction temperature increases. The derating of forward current is directly related to managing this thermal effect to maintain brightness and reliability.
• Forward Voltage:VF yawanci yana raguwa tare da haɓakar zafin jiki (coefficient mara kyau na zafin jiki).
• Tsawon zango:Kololuwar tsawon zango da babban tsawon zango suna ɗan ƙaura tare da haɓakar zafin jiki (yawanci zuwa tsawon zango mafi tsawo), wanda zai iya shafar fahimtar launi a cikin aikace-aikace masu mahimmanci.

5. Mechanical and Packaging Information

5.1 Package Dimensions and Polarity

This LED is packaged in a very compact surface-mount device. Its defining mechanical characteristic is a height of only 0.35 mm. The datasheet provides a detailed dimensional drawing, including length, width, and the position of the optical lens. This package follows the standard chip LED form factor. Polarity is indicated by a marking or a notch on the package. Correct orientation during assembly is critical, as applying reverse bias may damage the device.

5.2 Recommended Land Pattern Design

To ensure reliable solder joints and correct alignment during reflow soldering, it is recommended to adopt a specific pad layout (pad pattern). The datasheet provides these dimensions. Following this layout helps prevent issues such as tombstoning (where one end of the component lifts off the pad) or misalignment. A maximum recommended stencil thickness of 0.10mm is specified to control the amount of solder paste deposited.

6. Soldering and Assembly Guide

6.1 Reflow Soldering Profile

The datasheet provides two recommended infrared (IR) reflow soldering profiles: one for conventional (tin-lead) soldering processes and another for lead-free soldering processes. The lead-free profile typically features a higher peak temperature (e.g., 260°C) to accommodate the higher melting points of lead-free alloys such as SAC (tin-silver-copper). Both profiles include key parameters:

• Preheat/Ramp-up:A controlled heating phase that gradually increases the temperature of the circuit board and components, minimizing thermal shock and preventing solder paste splatter.
• Soak/Pre-reflow:A temperature plateau period that activates the flux in the solder paste, allows volatiles to escape, and equalizes the temperature across the entire assembly.
• Reflow/Peak:The temperature exceeds the liquidus of the solder, causing it to melt, wet the pads and component terminations, and form a proper metallurgical bond. The Time Above Liquidus (TAL) and peak temperature must be controlled within the LED's tolerance range (maximum 260°C for 5 seconds).
• Cooling:Controlled cooling process solidifies solder joints and minimizes thermal stress.

6.2 Storage and Handling Precautions

Proper storage is crucial for maintaining solderability. LEDs removed from their original moisture barrier packaging are hygroscopic and will absorb moisture. If stored outside of dry packaging for an extended period (exceeding 672 hours or 28 days), they must be baked (e.g., 24 hours at 60°C) prior to reflow to drive out moisture and prevent "popcorning" or package cracking during high-temperature soldering. For long-term storage, use sealed containers with desiccant or a nitrogen environment.

6.3 Cleaning

If post-soldering cleaning is required, only the specified solvents should be used. The datasheet recommends immersion in ethanol or isopropyl alcohol at room temperature for no more than one minute. The use of harsh or unspecified chemicals may damage the epoxy lens material, causing fogging, cracking, or discoloration.

7. Packaging and Ordering Information

LTST-C193KRKT-2A is supplied in industry-standard packaging suitable for automated assembly.

• Tape and Reel:Components are placed in embossed carrier tape and then sealed with cover tape. The carrier tape width is 8mm.
• Reel dimensions:Diameter 7 inches.
• Quantity per reel:5000 pieces.
• Minimum Order Quantity (MOQ):Remaining quantity is 500 pieces.
• Packaging Standard:Compliant with ANSI/EIA-481-1-A specification, ensuring compatibility with standard feeders on pick-and-place machines.

The part number LTST-C193KRKT-2A encodes specific product attributes, though complete naming convention details are typically found in a separate product selection guide.

8. Application Design Recommendations

8.1 Drive Circuit Design

LED is a current-driven device. The most critical part of the drive circuit is current control. A series resistor is the most common method, but its design requires careful consideration.

Calculate the series resistor (R_S):
R_S= (V_{power supply}- V_F) / I_F
Where:
V_{power supply}= Power supply voltage
V_F= LED forward voltage (for conservative design, use the maximum value from the datasheet, 2.2V)
I_F= Required forward current (must be ≤ 30 mA DC)

Example:For a 5V power supply and a target current of 20 mA:
R_S= (5V - 2.2V) / 0.020 A = 140 Ω. The closest standard value (e.g., 150 Ω) will be selected, resulting in a slightly lower current.

Important Consideration - Parallel Connection:It is not recommended to directly connect multiple LEDs in parallel using only one current-limiting resistor (Circuit B in the datasheet). Due to natural variations in the I-V characteristics of individual LEDs (even from the same bin), one LED may draw significantly more current than others, leading to uneven brightness and potential overloading of a single device. The recommended practice is to use a separate series resistor for each LED (Circuit A). For efficiently driving multiple LEDs, constant-current driver ICs or dedicated LED driver circuits are preferred.

8.2 Thermal Management

Even though the power is low, effective thermal management is still important for extending lifespan and ensuring stable performance. In designs where the ambient temperature near the LED is expected to rise significantly (e.g., inside a sealed enclosure, near other heat-generating components), a derating factor of 0.4 mA/°C must be applied. Ensuring adequate airflow or heat dissipation design in the PCB layout helps mitigate temperature rise.

8.3 ESD Protection

ESD threshold ya 1000V (HBM) no ya saboda haka LED na iya lalacewa da wutar lantarki ta yau da kullun. Ai wajibi ne a aiwatar da matakan kariya daga ESD:

• Yi amfani da tashin aiki mai kasa, kafet ɗin bene mai ɗaukar wutar lantarki, da bandeji.
• Ajiye kuma ka kwashe kayan a cikin fakitin da ke hana wutar lantarki ta tsaye.
• If the LED is connected to an external interface that may be exposed to ESD events, consider adding a Transient Voltage Suppression (TVS) diode or other protection circuits on the PCB.

9. Technical Comparison and Differentiation

The LTST-C193KRKT-2A primarily stands out in the market due to its ultra-thin profile of 0.35mm. Compared to standard chip LEDs, which typically have heights of 0.6mm or 1.0mm, this represents a reduction of 40-65%, enabling new industrial designs. The use of AlInGaP technology offers advantages over older GaAsP (Gallium Arsenide Phosphide) red LEDs, providing higher efficiency (more light output per mA), better temperature stability, and a more saturated, "purer" red color. Its compatibility with lead-free, high-temperature reflow processes makes it compliant with regulatory requirements and modern production lines, giving it a forward-looking advantage.

10. Frequently Asked Questions (FAQ)

Q1: Zan iya kunna wannan LED kai tsaye ta hanyar fil ɗin microcontroller 3.3V?
A: Possible, but calculation is needed. With a typical VF of about 1.9V, a series resistor is required to limit the current. However, you must ensure the MCU pin can supply the required current (e.g., 20mA) without exceeding its own specifications. Using a transistor as a switch is usually a safer and more flexible method.

Q2: Why is the luminous intensity specified at such a low current (2mA)?
A: 2mA is the standard test condition for low-current indicator LEDs. It facilitates comparison between different products and provides a benchmark. Intensity will be higher at higher currents, but the relationship is not completely linear, and efficiency may decrease.

Q3: The datasheet shows a very wide viewing angle (130°). What should I do if I need a more focused beam?
A: This specific package is designed for wide-angle emission. For a narrower beam, you need to select an LED in a different package (e.g., one with a smaller lens or a built-in reflector) or use external secondary optics such as a collimating lens.

Q4: How to interpret the binning code when ordering?
A: Specify the required intensity bin (G, H, J, or K) based on the minimum brightness your application requires. For example, if your design requires at least 5.0 mcd, you must order the J bin (4.50-7.10 mcd) or the K bin (7.10-11.20 mcd). Ordering "standard brightness" may result in any bin, which could lead to brightness mismatch in your product.

11. Practical Design and Usage Examples

Example 1: Status Indicator Light on Portable Devices
In slim smartphones or tablets, the space behind the glass or plastic panel is extremely limited. The 0.35mm height of this LED allows it to be placed directly on the main PCB under a thin light guide plate or diffusion film, indicating charging status, notification alerts, or backlighting for capacitive buttons without increasing the device's thickness.

Example 2: Membrane Switch Backlight
For industrial control panels or medical equipment with membrane keypads, uniform illumination under each key is crucial. Multiple LTST-C193KRKT-2A LEDs can be placed around the edges of the switch panel. Their wide viewing angle helps create an even backlight across the entire key area. The driving method using a resistor for each LED individually ensures consistent brightness for all keys, unaffected by VF variations.

Example 3: Integration into Ultra-Narrow Bezel Displays
Modern monitors and televisions pursue bezels that are only a few millimeters wide. This LED can be mounted on a flexible printed circuit (FPC) along the edge of the display panel to provide ambient mood lighting or a subtle power indicator, helping to achieve a stylish and aesthetically pleasing appearance without compromising the slim profile.

12. Introduction to Technical Principles

The LTST-C193KRKT-2A is based on AlInGaP semiconductor technology. This material system is epitaxially grown on a substrate. When a forward voltage is applied across the p-n junction, electrons and holes are injected into the active region where they recombine. In AlInGaP, this recombination primarily releases energy in the form of photons (light) in the red to yellow-orange part of the visible spectrum. The specific ratio of aluminum, indium, gallium, and phosphorus in the lattice determines the bandgap energy, and thus the wavelength of the emitted light. The "water clear" lens is typically made of epoxy or silicone that is transparent to the emission wavelength and is molded into a specific light output pattern (in this case, a wide viewing angle).

13. Industry Trends and Development

The trend for indicator and functional lighting LEDs continues towards miniaturization, higher efficiency, and greater integration. The component's 0.35mm height represents the ongoing effort to drive thinner packaging. Future developments may include thinner chip-scale packages (CSP), where the LED die is mounted directly without the traditional plastic encapsulation. Driven by automotive and industrial applications, achieving higher reliability and longer lifetime under higher temperature operating conditions is also a strong trend. Furthermore, for applications where color matching is critical, such as display backlighting and architectural lighting, the demand for precise color consistency and tighter binning tolerances is increasing. The underlying AlInGaP technology is continuously being improved for higher efficiency, promising reduced power consumption for a given light output in future generations.