LTST-C170TBKT-5A Blue SMD LED Datasheet - Dimensions 3.2x1.6x1.1mm - Voltage 2.8V - Power 76mW - English Technical Document

1. Product Overview

The LTST-C170TBKT-5A is a surface-mount device (SMD) light-emitting diode (LED) designed for modern, compact electronic applications. It belongs to a family of extra-thin chip LEDs, featuring a height of only 1.10 mm, making it suitable for applications with stringent space constraints. The device utilizes an InGaN (Indium Gallium Nitride) semiconductor chip, which is known for producing high-brightness blue light efficiently. It is packaged in industry-standard 8mm tape on 7-inch diameter reels, ensuring compatibility with high-speed automated pick-and-place and assembly equipment commonly used in electronics manufacturing.

This LED is classified as a green product, meaning it complies with the Restriction of Hazardous Substances (RoHS) directive. It is also designed to be compatible with infrared (IR) reflow soldering processes, which is the standard for assembling surface-mount components onto printed circuit boards (PCBs). Its electrical characteristics are compatible with integrated circuit (IC) logic levels, simplifying drive circuit design.

2. Technical Parameter Deep Dive

2.1 Absolute Maximum Ratings

These ratings define the limits beyond which permanent damage to the device may occur. They are specified at an ambient temperature (Ta) of 25°C.

• Power Dissipation (Pd): 76 mW. This is the maximum amount of power the LED package can safely dissipate as heat under continuous operation.
• Peak Forward Current (I_FP): 100 mA. This is the maximum allowable instantaneous forward current, typically specified under pulsed conditions (1/10 duty cycle, 0.1ms pulse width) to prevent overheating.
• DC Forward Current (I_F): 20 mA. This is the maximum recommended continuous forward current for reliable long-term operation.
• Operating Temperature Range: -20°C to +80°C. The device is guaranteed to function within this ambient temperature range.
• Storage Temperature Range: -30°C to +100°C. The device can be stored without degradation within these limits.
• Infrared Soldering Condition: 260°C for 10 seconds. This defines the peak temperature and time tolerance for reflow soldering processes.

2.2 Electrical & Optical Characteristics

These are the typical performance parameters measured at Ta=25°C and a standard test current (I_F) of 5 mA, unless otherwise noted.

• Luminous Intensity (I_V): 11.2 - 45.0 mcd (millicandela). This is a measure of the perceived brightness of the LED as seen by the human eye. The wide range indicates the device is available in different brightness bins (see Section 3).
• Viewing Angle (2θ_1/2): 130 degrees. This is the full angle at which the luminous intensity drops to half of its value at the central axis (0°). A 130° angle indicates a very wide viewing pattern.
• Peak Emission Wavelength (λ_P): 468 nm. This is the wavelength at which the optical output power is at its maximum.
• Dominant Wavelength (λ_d): 470.0 - 475.0 nm. This is the single wavelength that best represents the perceived color of the light, derived from the CIE chromaticity diagram. This range corresponds to a blue color.
• Spectral Line Half-Width (Δλ): 25 nm. O nọ́ yẹ̀yẹ̀n àwọn ìtàn-àkọọlẹ̀ tí a gbé jáde ní ìdajì agbára rẹ̀ tó pọ̀ jùlọ, tí ó fi hàn ìmọ́tọ́ àwọn ìtàn-àkọọlẹ̀ ìmọ́lẹ̀ aláwọ̀ àwo eléwé.
• Forward Voltage (V_F): 2.65 - 3.05 V (Typical 2.80V). Eyi ni ìsunkún fọ́tíjì káàkiri LED nígbà tí a bá ń fi àwọn ìyípadà ìdánilójú tí a sọ tẹ́lẹ̀ ṣiṣẹ́ rẹ̀. Ó jẹ́ àmì pàtàkì fún ṣíṣe àwọn ẹ̀rọ onírúurú ìdínkù ìyípadà.
• Reverse Current (I_R): 10 μA (max) at V_R=5V. LEDs are not designed for reverse bias operation. This parameter is tested for quality assurance only.

Important Notes: Luminous intensity is measured with a filter simulating the human eye response (CIE curve). The device is sensitive to Electrostatic Discharge (ESD); proper ESD precautions (wrist straps, grounded equipment) are mandatory during handling.

3. Binning System Explanation

To ensure consistency in mass production, LEDs are sorted into performance bins. The LTST-C170TBKT-5A uses a three-dimensional binning system.

3.1 Forward Voltage Binning

Units are in Volts (V) measured at I_F = 5 mA. Tolerance on 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

This allows designers to select LEDs with closely matched V_F for applications requiring uniform brightness when driven in parallel.

3.2 Luminous Intensity Binning

Units are in millicandelas (mcd) measured at I_F = 5 mA. Tolerance on each bin is ±15%.

• L1: 11.2 to 14.0 mcd
• L2: 14.0 to 18.0 mcd
• M1: 18.0 to 22.4 mcd
• M2: 22.4 to 28.0 mcd
• N1: 28.0 to 35.5 mcd
• N2: 35.5 to 45.0 mcd

This wide range of bins allows for selection based on application brightness requirements, from indicator lights to backlighting.

3.3 Dominant Wavelength Binning

Units are in nanometers (nm) measured at I_F = 5 mA. Tolerance is ±1 nm.

• Bin Code AD: 470.0 nm to 475.0 nm

This ensures a consistent shade of blue across all devices in this part number.

4. Performance Curve Analysis

The datasheet references typical performance curves which are essential for understanding device behavior under different conditions. While the specific graphs are not reproduced in the text, their implications are analyzed below.

4.1 Current vs. Voltage (I-V) Curve

The I-V curve for an InGaN LED like this one shows a characteristic exponential rise. The forward voltage (V_F) is relatively constant for a given current but has a negative temperature coefficient—it decreases slightly as the junction temperature increases. This must be considered in constant-voltage drive schemes to avoid thermal runaway.

4.2 Luminous Intensity vs. Forward Current

The light output (luminous intensity) is approximately proportional to the forward current in the typical operating range (up to 20mA). However, efficiency (lumens per watt) typically peaks at a current lower than the maximum rating and decreases at higher currents due to increased heat generation and "droop" effects in the semiconductor.

4.3 Spectral Distribution

The spectral output curve would show a single peak centered around 468-470 nm with a typical half-width of 25 nm. The dominant wavelength (perceived color) is derived from this spectrum. The spectrum is largely stable with current, but the peak wavelength may shift slightly (typically 0.1-0.2 nm/°C) with changes in junction temperature.

5. Mechanical & Package Information

5.1 Package Dimensions

The LED features an industry-standard EIA package outline. Key dimensions include a body size of approximately 3.2mm (length) x 1.6mm (width) and the defining ultra-thin profile of 1.10mm (height). All dimensional tolerances are typically ±0.10mm unless otherwise specified on the detailed mechanical drawing. The lens is water clear, which is optimal for blue LEDs as it does not alter the color.

5.2 Polarity Identification & Pad Design

The component has an anode and cathode. Polarity is typically indicated by a marking on the package, such as a notch, dot, or cut corner. The datasheet includes suggested soldering pad dimensions for PCB layout. Following these recommendations is crucial for achieving a reliable solder joint, proper alignment during reflow, and managing thermal stress. The pad design also aids in preventing tombstoning (one end lifting during soldering).

6. Soldering & Assembly Guidelines

6.1 Reflow Soldering Profile

The device is compatible with infrared reflow soldering for lead-free (Pb-free) solder paste. A suggested profile is provided, which generally follows JEDEC standards. Key parameters include:

• Pre-heat: 150-200°C for up to 120 seconds to gradually heat the board and activate flux.
• Peak Temperature: Maximum of 260°C.
• Time Above Liquidus (TAL): The time within 5°C of the peak temperature should be limited to a maximum of 10 seconds. Reflow should not be performed more than twice.

The exact profile must be characterized for the specific PCB design, components, and oven used.

6.2 Hand Soldering

If hand soldering is necessary, extreme care must be taken:

• Soldering iron temperature should not exceed 300°C.
• Contact time should be limited to a maximum of 3 seconds per pad.
• Hand soldering should be performed only once to avoid thermal damage to the plastic package and the semiconductor die.

6.3 Storage & Handling

Storage (Sealed Bag): LEDs are moisture-sensitive (MSL). When stored in the original moisture-proof bag with desiccant, they should be kept at ≤30°C and ≤90% RH and used within one year of the bag seal date. Storage (After Bag Opening): Once opened, the ambient should not exceed 30°C / 60% RH. It is recommended to complete IR reflow within 672 hours (28 days) of exposure. For longer exposure, baking at approximately 60°C for at least 20 hours is required before soldering to remove absorbed moisture and prevent "popcorning" (package cracking during reflow).

6.4 Cleaning

If cleaning after soldering is required, only specified alcohol-based solvents like isopropyl alcohol (IPA) or ethyl alcohol should be used. The LED should be immersed at normal temperature for less than one minute. Unspecified chemical cleaners can damage the plastic package material or the lens.

7. Packaging & Ordering Information

7.1 Tape and Reel Specifications

The LEDs are supplied in embossed carrier tape, sealed with a cover tape, and wound on 7-inch (178mm) diameter reels.

• Quantity per Reel: 3000 pieces.
• Minimum Order Quantity (MOQ): 500 pieces for remainder quantities.
• Packaging Standard: Complies with ANSI/EIA-481-1-A-1994.
• Quality: The maximum number of consecutive missing components ("missing lamps") in the tape is two.

This packaging is optimized for automated SMT assembly lines.

8. Application Suggestions

8.1 Typical Application Scenarios

Due to its ultra-thin profile, wide viewing angle, and blue color, this LED is well-suited for:

• Status Indicators: Power, connectivity, or activity indicators in consumer electronics, networking equipment, and appliances.
• Backlighting: Edge-lighting for small LCD displays, keypad illumination, or decorative lighting in thin devices.
• Consumer Electronics: Decorative lighting in smartphones, tablets, gaming peripherals, and wearables where height is critical.
• Automotive Interior Lighting: For dashboard indicators or ambient lighting, considering the operating temperature range.

8.2 Design Considerations

Current Driving: Always use a series current-limiting resistor or a constant-current driver circuit. Driving the LED directly from a voltage source will result in excessive current and rapid failure. The resistor value can be calculated using Ohm's Law: R = (V_supply - V_F) / I_F. Thermal Management: Ko da yake zafi da ake samu yana da ƙasa, tabbatar da isasshen yanki na tagulla na PCB a kusa da kushin zafi (idan akwai) ko sanyaya allon gabaɗaya zai taimaka wajen kiyaye ingancin LED da tsawon rayuwa, musamman lokacin aiki kusa da matsakaicin halin yanzu ko a yanayin zafi mai girma. Optical Design: Ruwan-ruwan ruwa mai tsabta da kallon fadi suna ba da tsarin haske mai faɗi, mai yaduwa. Don haske mai mai da hankali, ana iya buƙatar ruwan tabarau na waje ko jagororin haske. Fitowar hasken shuɗi yana cikin kewayon da za a iya amfani da shi tare da phosphors don ƙirƙirar farin haske a wasu aikace-aikace.

9. Technical Comparison & Differentiation

The primary differentiating factors of the LTST-C170TBKT-5A are its ultra-thin 1.10mm height and its use of a high-brightness InGaN chip. Compared to older technology like GaP (Gallium Phosphide) blue LEDs, InGaN offers significantly higher luminous efficiency and a more saturated blue color. The thin profile is a key advantage over standard SMD LEDs (which are often 1.5-2.0mm tall) in space-constrained modern electronics. The wide 130-degree viewing angle is also notable compared to narrower-angle LEDs used for focused illumination.

10. Frequently Asked Questions (FAQ)

10.1 What is the difference between Peak Wavelength and Dominant Wavelength?

Peak Wavelength (λ_P): The specific wavelength where the optical power output is literally at its maximum. It is a physical measurement.
Dominant Wavelength (λ_d): A calculated value from the CIE color chart that represents the single wavelength of monochromatic light that would appear to have the same color as the LED's output to the human eye. It defines the perceived color. For a blue LED, they are often close, as in this case (468nm vs. 470-475nm).

10.2 Can I drive this LED at 20mA continuously?

Yes, 20mA is the maximum recommended DC Forward Current. For optimal lifetime and efficiency, driving it at a lower current, such as 5mA (the test condition) or 10mA, is often sufficient for indicator purposes and reduces heat generation.

10.3 Me ya sa kariyar ESD ke da muhimmanci ga LEDs?

The semiconductor junction in an LED, especially high-brightness InGaN types, is very sensitive to high-voltage electrostatic discharges. A static shock that is imperceptible to a human can instantly degrade or destroy the LED's light output capability by damaging the microscopic semiconductor layers. Always handle in an ESD-safe environment.

11. Practical Design Case Study

Scenario: Designing a low-power status indicator for a portable Bluetooth speaker. The indicator must be visible in daylight, have a wide viewing angle, and fit within a 1.5mm tall enclosure.
Selection Rationale: The LTST-C170TBKT-5A is chosen for its 1.10mm height and 130° viewing angle. The blue color provides good contrast and is commonly associated with Bluetooth technology.
Circuit Design: The speaker's main board has a 3.3V rail. Targeting a forward current of 10mA for good brightness and efficiency. Using the typical V_F of 2.8V: R = (3.3V - 2.8V) / 0.01A = 50 Ohms. A standard 51-ohm resistor is selected. The power dissipation in the LED is P = V_F * I_F = 2.8V * 0.01A = 28mW, well below the 76mW maximum.
Layout: The suggested pad layout from the datasheet is used on the PCB. A small keep-out area under the LED is maintained to prevent solder wicking.

12. Operating Principle Introduction

Light-emitting diodes are semiconductor devices that convert electrical energy directly into light through a process called electroluminescence. The LTST-C170TBKT-5A uses an InGaN-based heterostructure. 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 (the quantum well). When an electron recombines with a hole in this region, energy is released in the form of a photon (light particle). The specific energy bandgap of the InGaN material determines the wavelength (color) of the emitted photon, which in this case is in the blue spectrum (~470 nm). The water-clear epoxy package acts as a lens, shaping the light output and providing environmental protection.

13. Technology Trends

The development of blue InGaN LEDs was a foundational breakthrough in solid-state lighting, enabling the creation of white LEDs (via phosphor conversion) and full-color displays. Current trends in SMD LEDs like this one continue to focus on:

• Increased Efficiency (lm/W): Reducing energy consumption for the same light output.
• Miniaturization: Further reduction in package size (footprint and height) for next-generation ultra-compact devices.
• Improved Color Consistency: Tighter binning tolerances for applications requiring uniform color, such as large-area backlighting or video walls.
• Higher Reliability & Lifetime: Ukuvuselelwa kwezinto zokupakisha nokuklanywa kwe-chip ukuze kumelane namazinga okushisa aphezulu okusebenza nezindawo ezinzima, ukwandisa ukusetshenziswa kwezimoto nezimboni.

Ukusuka ezintweni ezingenamthofu nezingenamakhaloni ngokuhambisana nemithetho yezemvelo nakho kuyindlela ejwayelekile yemboni.