LTST-C281TBKT-5A Blue SMD LED Datasheet - 0.35mm Ultra-Thin Height - 3.15V Max Voltage - 76mW - Technical Documentation

1. Product Overview

The LTST-C281TBKT-5A is a surface-mount device (SMD) chip LED designed specifically for modern space-constrained electronic applications. Its notable feature is an extremely slim profile, with a package height of only 0.35 mm. This makes it ideally suited for applications where component thickness is a critical design parameter, such as ultra-thin displays, mobile devices, and backlight modules.

This device utilizes an InGaN (Indium Gallium Nitride) semiconductor chip, renowned for generating efficient blue light. The LED is encapsulated in a transparent lens material that does not diffuse light, resulting in a focused, high-intensity output. It is packaged on 8 mm carrier tape and supplied on standard 7-inch diameter reels, making it fully compatible with high-speed automated pick-and-place assembly equipment used in high-volume manufacturing.

Key benefits include compliance with the RoHS (Restriction of Hazardous Substances) directive, making it an environmentally friendly "green product." It is also designed to be compatible with infrared (IR) reflow soldering processes, the standard process for assembling surface-mount components onto printed circuit boards (PCBs).

2. Cikakken Bayanin Sigogi na Fasaha

2.1 Absolute Maximum Ratings

These ratings define the limits beyond which permanent damage to the device may occur. They are not intended for normal operation.

• Power Dissipation (Pd):76 mW. This is the maximum power that the LED package can dissipate as heat without degrading performance or reliability.
• Peak Forward Current (I_FP):100 mA. This current can only be applied under pulse conditions, specifically with a duty cycle of 1/10 and a pulse width of 0.1 ms. Exceeding this value may cause instantaneous chip failure.
• DC Forward Current (I_F):20 mA. This is the maximum continuous forward current recommended for reliable long-term operation.
• Operating Temperature Range (T_opr):-20°C to +80°C. The LED is designed to operate within this ambient temperature range.
• Storage Temperature Range (T_stg):-30°C to +100°C.
• Infrared welding conditions:Can withstand 260°C for 10 seconds, which is consistent with typical lead-free (Pb-free) reflow soldering profiles.

2.2 Electrical and Optical Characteristics

These parameters are measured under standard test conditions with an ambient temperature (T_a) of 25°C and a forward current (I_F) of 5mA, unless otherwise specified.

• Luminous intensity (I_V):ranges from a minimum of 11.2 mcd to a maximum of 45.0 mcd, with a typical value provided. This measures the LED brightness as perceived by the human eye.
• Viewing angle (2θ_1/2):130 digiri. Wannan faɗin kallon yana nuna cewa haske yana fitarwa cikin faɗin tsarin Lambert, wanda ya dace da hasken yanki maimakon hasken mai da hankali.
• Kololuwar tsayin zango (λ_P):Matsakaicin ƙima 468 nm. Wannan shine tsayin zango mafi girman fitarwar ƙarfin bakan.
• Babban tsayin zango (λ_d):An ƙayyade shi tsakanin 470.0 nm zuwa 475.0 nm. Wannan shine tsayin zango guda ɗaya wanda ya fi wakiltar launin da ido ke gani, wanda aka samo daga taswirar launi na CIE.
• Ramin rabin faɗin bakan (Δλ):Matsakaicin ƙima 25 nm. Wannan yana nuna tsarkin bakan; ƙaramin adadi yana nuna mafi kyawun haɗakar launi na tushen haske.
• Ƙarfafan ƙarfin lantarki (V_F):A 5mA, kewayon daga 2.65V zuwa 3.15V. Wannan shine raguwar ƙarfin lantarki a ƙarshen LED lokacin da aka kunna igiyar ruwa.
• Reverse current (I_R):When a reverse voltage (V_R) of 5V is applied, the maximum is 10 μA.Important Note:This LED is not designed for reverse bias operation; this test parameter is for quality assurance only.

3. Bayanin Tsarin Rarrabawa

To ensure consistency in mass production, LEDs are sorted into performance bins based on key parameters. The LTST-C281TBKT-5A employs a three-dimensional binning system.

3.1 Forward Voltage Binning

Unit is volts (V), measured at I = 5mA._FThe tolerance for each bin is ±0.1V.

• Bin code 1: 2.65V (min) to 2.75V (max)
• Bin code 2: 2.75V to 2.85V
• Bin code 3: 2.85V to 2.95V
• Bin code 4: 2.95V to 3.05V
• Bin code 5: 3.05V to 3.15V

Wannan yana bawa masu zane damar zaɓar V don aikace-aikacen da rabon kwarara mai daidaito a cikin jerin haɗin gwiwa yake da mahimmanci._FLED masu daidaitaccen daidaito.

3.2 Luminous Intensity Binning

Naúrar ita ce millicandela (mcd), ana aunawa a lokacin I_F= 5mA. Kuskuren kowane mataki shine ±15%.

• Lambar mataki L: 11.2 mcd zuwa 18.0 mcd
• Lambar mataki M: 18.0 mcd zuwa 28.0 mcd
• Lambar mataki N: 28.0 mcd zuwa 45.0 mcd

This binning ensures the final application has predictable brightness levels.

3.3 Dominant Wavelength Binning

The unit is nanometers (nm), measured at I_F= 5mA. The tolerance is ±1 nm.

• Bin code AD: 470.0 nm to 475.0 nm

This strict color control ensures a consistent blue hue across all LEDs from the same production batch.

4. Performance Curve Analysis

Although the datasheet references specific graphical curves (e.g., Figure 1 for spectral distribution, Figure 5 for viewing angle), typical behavior can be inferred from the parameters:

• I-V (Current-Voltage) Characteristics:As a semiconductor diode, the relationship between the forward current and forward voltage of an LED will be exponential. The V specified at 5mA provides a key operating point._FIt is strongly recommended to drive the LED using a constant current source rather than a constant voltage to ensure stable light output.
• Temperature Dependence:The luminous intensity of InGaN LEDs typically decreases as the junction temperature increases. Although the operating temperature range is up to 80°C, designers should consider thermal management to maintain the required brightness level, especially when driving at or near the maximum DC current.
• Spectral Shift:The peak wavelength and dominant wavelength may shift slightly with changes in drive current and junction temperature, although the binning system helps mitigate visible color differences.

5. Bayanin Injiniya da Kunshewa

5.1 Girman Kunshewa

The primary mechanical feature is a package height of 0.35 mm. All other dimensions conform to the standard outline for this type of chip LED as defined by EIA (Electronic Industries Alliance), ensuring compatibility with industry-standard mounting equipment and pad layouts. The datasheet provides a detailed dimensional drawing with a tolerance of ±0.10 mm for precise PCB pad design.

5.2 Gane Halayen Ƙarfi

The datasheet includes a diagram showing the cathode and anode markings on the LED package. Correct polarity must be observed during assembly, as applying reverse voltage may damage the device.

5.3 Girman Filin Walda da Ake Ba da Shawara

The recommended pad layout (land pattern) for the PCB is provided. Adhering to these recommendations is crucial for achieving reliable solder joints, proper alignment during reflow soldering, and effective heat dissipation from the LED terminals.

6. Soldering and Assembly Guide

6.1 Reflow Soldering Profile

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

• Preheating:Ramp up to 150-200°C.
• Preheating Time:Maximum 120 seconds, to achieve uniform heating and activate solder paste flux.
• Peak Temperature:Maximum 260°C.
• Time Above Liquidus:The LED should be exposed to the peak temperature for a maximum of 10 seconds. This process should not be repeated more than twice.

This profile is based on JEDEC standards to ensure reliable assembly without subjecting the LED package to excessive thermal stress.

6.2 Hand Soldering

If hand soldering must be performed, extreme caution is required:

• Soldering Iron Temperature:Maximum 300°C.
• Welding time:The maximum time per solder joint is 3 seconds.
• Frequency:Should be performed only once to avoid thermal damage.

6.3 Cleaning

If cleaning is required after soldering, only specified solvents should be used to avoid damaging the plastic lens or package. Recommended cleaning agents are ethanol or isopropanol. The LED should be immersed at room temperature for less than one minute.

6.4 Ajiyewa da Aiki

• ESD (Electrostatic Discharge) Prevention Measures:LEDs are sensitive to static electricity. Use wrist straps, anti-static mats, and properly grounded equipment during handling.
• Moisture Sensitivity:When LEDs are in their original sealed moisture barrier bag with desiccant, the shelf life is 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.
• Floor Life:It is recommended that components removed from the original packaging undergo infrared reflow soldering within 672 hours (28 days). For storage outside the original bag for longer periods, use a sealed container with desiccant. Components stored beyond 672 hours should be baked at approximately 60°C for at least 20 hours prior to soldering to remove absorbed moisture and prevent "popcorning" during reflow.

7. Marufi da Bayanin Oda

LTST-C281TBKT-5A is supplied in tape and reel format compatible with automated assembly.

• Carrier tape width: 8mm.
• Reel size:Standard 7-inch diameter.
• Quantity per reel:5000 pieces.
• Minimum Order Quantity (MOQ):Minimum order quantity is 500 pieces.
• Packaging Standard:Complies with ANSI/EIA-481 specification. Empty pockets in the carrier tape are sealed with cover tape.

8. Shawarar Aikace-aikace

8.1 Yanayin Aikace-aikace na Al'ada

• Status Indicator:Power, connection, or function status lights in consumer electronics, home appliances, and networking equipment.
• Backlight:Edge lighting for LCD displays, keyboard illumination in mobile devices and remote controls.
• Decorative Lighting:Accent lighting in automotive interiors, signage, and decorative luminaires.
• Sensor Systems:As a light source for optical sensors.

8.2 Design Considerations

• Current Limiting:Always use a series current-limiting resistor or constant-current drive circuit. Do not connect directly to a voltage source.
• Thermal Management:Although power consumption is low, if operating at high ambient temperatures or near maximum current, ensure sufficient copper area or thermal vias under the PCB pad to keep the junction temperature within a safe range.
• Optical Design:A transparent lens produces a focused beam. For diffuse or wider area illumination, an external diffuser or light guide plate may be required.
• Binning Selection:For applications requiring uniform color and brightness (e.g., multi-LED arrays), specify the required binning codes (V_F, I_V, λ_d).

9. Technical Comparison and Differentiation

The primary differentiating factor of the LTST-C281TBKT-5A is its ultra-low 0.35mm profile. Compared to standard chip LEDs, which are typically 0.6mm or higher, this device enables thinner end products. The use of InGaN technology provides higher efficiency and brighter blue output compared to older technologies. Its compatibility with standard infrared reflow soldering and tape-and-reel packaging makes it a plug-and-play solution for automated, high-volume production lines, requiring no special processes.

10. Frequently Asked Questions (FAQ)

Q: What is the difference between peak wavelength and dominant wavelength?
A: Peak wavelength (λ_P) is the physical wavelength at which the LED emits the most optical power. Dominant wavelength (λ_d) is a calculated value representing the single monochromatic light wavelength that matches the color of the LED as perceived by the human eye. λ_dYawanci yana da alaƙa da aikace-aikacen da suka dogara da launi.

Tambaya: Zan iya sarrafa wannan LED a 20mA a ci gaba?
Amsa: I, 20mA shine shawarar mafi girman kwararar DC ta gaba. Don samun mafi kyawun rayuwa da la'akari da tasirin zafin jiki, idan an kai ga haske da ake buƙata, yawanci sarrafa da ƙaramin ƙarfi (kamar 10-15mA) kyakkyawan aiki ne.

Tambaya: Me yasa ake da tsarin rarrabuwa?
Amsa: Samfurin semiconductor yana da bambance-bambancen yanayi. Rarrabuwa yana rarraba LED zuwa ƙungiyoyin da ke da sarrafa halaye (ƙarfin lantarki, haske, launi) sosai, yana ba masu zane damar yin amfani da abubuwa masu daidaituwa, masana'antun kuma su sayar da samfuran da ke da tabbataccen kewayon aiki.

Tambaya: Ana buƙatar mai sanyaya zafi?
Amsa: Ga yawancin aikace-aikacen da ke cikin yanayin 5mA ko ƙasa da haka, saboda ƙarancin amfani da wutar lantarki (maksimum 76mW), ba a buƙatar mai sanyaya zafi na musamman. Duk da haka, don aiki mai ƙarfin wutar lantarki ko yanayin zafi mai girma, ya kamata a yi la'akari da sarrafa zafi ta hanyar PCB.

11. Practical Design Case Studies

Scene:Design a low-profile status indicator for a wearable fitness tracker.
Requirements:厚度<0.5毫米，蓝色，在日光下可见，由3.3V系统电源轨供电。
Solution:The 0.35mm height of the LTST-C281TBKT-5A perfectly fits the mechanical constraints. Selecting a bin code from the AD (470-475nm) wavelength bin ensures the required blue color. To drive it from 3.3V, calculate a series resistor. Assuming a typical V_Fof 2.9V (from Bin 3) and a target I_Fof 5mA: R = (3.3V - 2.9V) / 0.005A = 80Ω. A standard 82Ω resistor will be used. At 5mA, the luminous intensity will be between 11.2 and 45.0 mcd (depending on I_Vbin), which is sufficient for a status indicator. The device's compatibility with reflow soldering allows it to be assembled alongside other SMD components on the tracker's main PCB.

12. Introduction to Technical Principles

LTST-C281TBKT-5A is based on InGaN (Indium Gallium Nitride) semiconductor technology. When a forward voltage is applied to the p-n junction of this material, electrons and holes recombine, releasing energy in the form of photons (light). The specific ratio of indium to gallium in the crystal lattice determines the bandgap energy, which in turn determines the wavelength (color) of the emitted light. For this LED, its composition is tuned to emit in the blue region of the spectrum (approximately 470nm). A transparent epoxy resin lens encapsulates and protects the semiconductor chip while allowing light to exit with minimal absorption or scattering.

13. Industry Trends

The trend for SMD LEDs continues towards higher efficiency (more light output per watt of electrical input), smaller package sizes, and lower profiles to enable thinner consumer electronics. Concurrently, there is a strong drive for improved color consistency and tighter binning tolerances to meet the demands of high-quality display backlighting and architectural lighting. The shift to lead-free (Pb-free) soldering and RoHS compliance (supported by this device) is now a global industry standard. Future developments may include integrated driver circuits within the LED package and enhanced reliability for operation in harsher environments.