LTST-C19FD1WT Full-Color SMD LED Datasheet - Dimensions 3.2x1.6x0.55mm - Voltage 2.0-3.8V - Power 0.08W - Technical Documentation

1. Product Overview

LTST-C19FD1WT is a full-color surface-mount device (SMD) LED lamp, specifically designed for modern space-constrained electronic applications. It integrates three different LED chips within an ultra-thin package, enabling a single component footprint to produce multiple colors. This design is particularly advantageous for applications requiring status indication, backlighting, or compact display elements, while not wanting to sacrifice color capability.

Its miniature size and compatibility with automated assembly processes make it a versatile choice for high-volume manufacturing. The device complies with the RoHS (Restriction of Hazardous Substances) standard, ensuring it adheres to global environmental regulations for electronic components.

1.1 Core Advantages and Target Market

The primary advantage of this LED is its integration of blue (InGaN), green (InGaN), and orange (AlInGaP) light sources into an EIA-standard package with a height of only 0.55mm. This multi-chip configuration achieves similar color functionality without the need for multiple discrete LEDs, thereby saving valuable PCB (Printed Circuit Board) space.

This device is primarily targeted at the following application areas:

• Telecommunications equipment:Status indicators on routers, modems, and mobile phones.
• Office Automation:Backlighting for keyboards and keys in laptops and peripherals.
• Consumer Electronics & Home Appliances:Power, Mode, or Function Indicator Lights.
• Industrial Equipment:Panel Indicator Lights and Operator Interface Components.
• Micro-Display and Signage:Small-scale information or symbol illumination.

Its compatibility with infrared (IR) reflow soldering processes meets the requirements of standard surface-mount technology (SMT) assembly lines, facilitating efficient and reliable board mounting.

2. Technical Parameters: In-depth and Objective Interpretation

This section provides a detailed analysis of the electrical, optical, and thermal characteristics defined in the datasheet. Understanding these parameters is crucial for proper circuit design and ensuring long-term reliability.

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 and should be avoided in design.

• Power Dissipation (Pd):Blue/green chip is 80 mW, orange chip is 75 mW. This is the maximum allowable power that the LED can dissipate as heat when the ambient temperature (Ta) is 25°C. Exceeding this limit may lead to thermal runaway and performance degradation.
• DC Forward Current (IF):Blue/green chip is 20 mA, orange chip is 30 mA. This is the recommended maximum continuous forward current for normal operation. It is typical for the orange chip (AlInGaP technology) to have a higher rating compared to InGaN.
• Peak Forward Current:Blue/green chips: 100 mA, orange chips: 80 mA (duty cycle 1/10, pulse width 0.1ms). This rating applies only to brief pulse operation and should not be used for DC design calculations.
• Temperature Range:Operating Temperature: -20°C to +80°C; Storage Temperature: -30°C to +100°C. Device functionality is guaranteed within the operating temperature range. Prolonged storage outside the specified range may affect material properties.
• Infrared Welding Conditions:Peak temperature 260°C, maximum duration 10 seconds. This defines the thermal profile tolerance for lead-free (Pb-free) solder reflow process.

2.2 Electro-Optical Characteristics

These parameters are measured under standard test conditions (Ta=25°C, IF=20mA) and define the performance of the device.

• Luminous Intensity (Iv):Measured in millicandelas (mcd). The datasheet provides the minimum and maximum values for each color, which are further subdivided into different bins (see Section 3). Typical values are: Blue: 28-180 mcd, Green: 71-450 mcd, Orange: 45-180 mcd. Green chips typically exhibit higher efficiency.
• Viewing Angle (2θ1/2):Typically 130 degrees. This wide viewing angle indicates the use of a diffused lens, which distributes light over a broad area rather than focusing it into a beam. This is ideal for status indicators that need to be visible from various angles.
• Forward Voltage (VF):Voltage drop across the LED when conducting 20mA current. Typical/Maximum values: Blue/Green: 3.5V/3.8V; Orange: 2.0V/2.4V. This is a key parameter for driver design. The lower VF requirement of the orange chip necessitates consideration of different current limiting schemes if colors are driven independently.
• Peak Emission Wavelength (λp) vs. Dominant Wavelength (λd):λp is the wavelength corresponding to the highest point of the emission spectrum. λd is the single wavelength perceived by the human eye. Typical values: Blue: λp=468nm, λd=470nm; Green: λp=520nm, λd=525nm; Orange: λp=611nm, λd=605nm. The difference between λp and λd stems from the shape of the emission spectrum and the photopic response of the human eye.
• Spectral Line Half-Width (Δλ):The width of an emission spectrum at half its maximum intensity. Typical values: Blue: 26nm, Green: 35nm, Orange: 17nm. As shown by the orange light, a narrower Δλ indicates a purer spectral color.
• Reverse Current (IR):Maximum 10 µA at VR=5V. LEDs are not designed for reverse bias operation. This test parameter indicates the presence of a very small leakage current. Applying a significant reverse voltage will damage the device.

3. Explanation of the Grading System

To manage natural variations in semiconductor manufacturing, LEDs are binned according to performance. This allows designers to select components that meet specific luminous intensity requirements.

3.1 Luminous Intensity Grading

LTST-C19FD1WT employs a letter-based luminous intensity binning system, with an internal tolerance of +/-15% per bin. Due to inherent material efficiency variations, the available bins differ for each color.

• Blue (InGaN):Gear N (28-45 mcd), P (45-71 mcd), Q (71-112 mcd), R (112-180 mcd).
• Green light (InGaN):Gear Q (71-112 mcd), R (112-180 mcd), S (180-280 mcd), T (280-450 mcd). Note that its upper range is higher than that of blue light.
• Orange light (AlInGaP):Bin P (45-71 mcd), Q (71-112 mcd), R (112-180 mcd).

When ordering, specifying the bin code ensures brightness consistency throughout the entire production batch. For example, specifying "Green, Bin T" guarantees obtaining the green LED chips with the highest brightness in this product.

4. Performance Curve Analysis

Although the datasheet references typical curves, their general interpretation is based on standard LED physical characteristics.

• IV Curve (Current vs. Voltage):The forward voltage (VF) increases logarithmically with current. The curve for orange light chips (AlInGaP) typically has a lower knee voltage (approximately 1.8-2.0V vs. approximately 3.0-3.2V) compared to blue/green light chips (InGaN). Beyond the knee point, the voltage rise becomes more linear.
• Luminous Intensity vs. Forward Current:Intensity is roughly proportional to the forward current until the maximum rated current is reached. However, at extremely high currents, efficiency (lumens per watt) typically decreases due to increased heat.
• Temperature Characteristics:Luminous intensity typically decreases as junction temperature increases. Forward voltage also decreases with rising temperature (VF has a negative temperature coefficient).
• Spectral Distribution:Each chip emits light within a narrow wavelength band, with a peak at λp. The spectrum of orange AlInGaP is generally narrower than that of blue and green InGaN spectra.

5. Mechanical and Packaging Information

5.1 Package Dimensions and Pin Assignment

This device complies with industry-standard SMD package dimensions. Key dimensions include a body size of approximately 3.2mm x 1.6mm and a height of only 0.55mm. Pin assignment is crucial for correct orientation: Pin 1: Blue (InGaN) anode, Pin 2: Orange (AlInGaP) anode, Pin 3: Green (InGaN) anode. The cathodes of all three chips are internally connected to the remaining terminal. The exact pad layout shown in the "Recommended Printed Circuit Board Mounting Pad" diagram in the datasheet must be followed to ensure proper soldering and thermal performance.

5.2 Polarity Identification

Polarity is typically indicated by a marking on the LED package, such as a dot, notch, or bevel near Pin 1. The PCB silkscreen should clearly reflect this marking to prevent assembly errors. Incorrect polarity will cause the LED not to illuminate and may stress the device if the drive circuit applies a high reverse voltage.

6. Welding and Assembly Guide

6.1 Reflow Soldering Parameters

This device is rated for lead-free (Pb-free) infrared reflow soldering. The recommended thermal profile includes a preheat zone (150-200°C), a controlled ramp-up to a peak temperature of 260°C maximum, and a peak temperature dwell time (TAL), where the peak temperature is maintained for up to 10 seconds. The total preheat time should not exceed 120 seconds. These parameters are based on JEDEC standards to prevent thermal shock and damage to the epoxy package and internal bond wires. The thermal profile should be characterized according to the specific PCB assembly conditions.

6.2 Storage and Handling

• ESD (Electrostatic Discharge) Precautions:LED is sensitive to ESD. Operation should be performed at an ESD-protected workstation using a grounded wrist strap and conductive foam.
• Moisture Sensitivity Level (MSL):该器件等级为MSL 3。当原装防潮袋打开后，元件必须在暴露于工厂车间条件（<30°C/60% RH）后的168小时（1周）内完成焊接。如果超过此时间，需要在60°C下烘烤至少20小时以去除吸收的水分，防止回流焊过程中出现“爆米花”现象。
• Long-term storage:Unopened bags should be stored in an environment of ≤30°C and ≤90% RH. Opened devices should be stored in a dry cabinet or a sealed container with desiccant.

6.3 Cleaning

Post-solder cleaning (if necessary) should use mild alcohol-based solvents, such as isopropyl alcohol (IPA) or ethanol. A brief soak at room temperature (less than one minute) is recommended. The use of harsh or unspecified chemicals may damage the lens material or package markings.

7. Packaging and Ordering Information

The LTST-C19FD1WT is supplied in industry-standard embossed carrier tape on a 7-inch (178mm) diameter reel. Each reel contains 3000 pieces. The carrier tape and reel dimensions comply with the ANSI/EIA-481 specification, ensuring compatibility with automated placement equipment. For quantities less than a full reel, the typical minimum packaging quantity for the remainder is 1000 pieces.

8. Application Recommendations

8.1 Typical Application Circuit

Each color chip must be independently driven using its own current-limiting resistor or constant current driver. The resistor value (R) is calculated using Ohm's Law: R = (Supply Voltage - LED Forward Voltage) / Forward Current. For example, to drive a blue LED with a 5V supply, target IF of 20mA, and typical VF of 3.5V: R = (5V - 3.5V) / 0.02A = 75 ohms. A standard 75Ω or 82Ω resistor is suitable. The resistor's power rating should be at least I²R = (0.02)² * 75 = 0.03W, so a 1/10W (0.1W) resistor is sufficient. A microcontroller or dedicated LED driver IC can be used for PWM (Pulse Width Modulation) dimming or dynamic color mixing.

8.2 Design Considerations

• Thermal Management:Duk da yin amfani da wutar lantarki ya yi ƙasa, tabbatar da isasshen yanki na tagulla na PCB a kusa da filin LED yana taimakawa wajen fitar da zafi daga yankin haɗin gwiwa, don haka kiyaye haske da tsawon rayuwa.
• Daidaita halin yanzu:Don samun daidaitaccen haske na bayyane lokacin da launuka daban-dabin suka kunna tare, dole ne a yi la'akari da ƙarfin haske daban-dabin da kuma hankalin idon mutum (amshan haske). Wataƙila za a buƙaci daidaita halin yanzu daban (misali, amfani da ƙananan halin yanzu ga guntu kore mai haske) don samun daidaitaccen farin haske ko sauran gaurayawan launuka.
• Kariya daga jujjuyawar ƙarfin lantarki:In circuits where LEDs may be exposed to reverse bias (e.g., in multiplexed arrays), it is recommended to connect a shunt diode in parallel with each LED string to protect the device.

9. Technical Comparison and Differentiation

The key differentiation of the LTST-C19FD1WT lies in its achievement of "full-color" capability within an ultra-thin 0.55mm package. Compared to using three separate monochromatic 0603 or 0402 LEDs, this integrated solution significantly saves space, simplifies the mounting process (one component vs. three), and may enable better color mixing due to the closer proximity of the light sources. The use of InGaN for blue/green chips and AlInGaP for the orange chip provides high efficiency and good color saturation across the spectrum. Alternative approaches might use white LEDs with color filters or dedicated RGB LED packages, which could be thicker or have different drive voltage requirements.

10. Frequently Asked Questions (Based on Technical Parameters)

10.1 Can I drive all three colors simultaneously to produce white light?

Yes, by driving the red (orange), green, and blue chips with an appropriate current ratio, you can mix light to produce various colors, including white. However, the specific orange wavelength (dominant wavelength 605-611nm) is not a deep red, so compared to LEDs using a true red chip, the resulting "white light" may have a slightly warmer or more limited color gamut. Achieving a specific white point (e.g., D65) requires precise current control and may involve calibration.

10.2 Me ya sa mafi girman ƙarfin kwarara na guntu na lemu ya bambanta?

The orange chip uses AlInGaP semiconductor technology, while the blue and green ones use InGaN. These different material systems have inherent differences in current density tolerance, internal efficiency, and thermal characteristics. This leads manufacturers to specify a higher safe continuous current for the orange chip (30mA vs. 20mA) under the same package thermal constraints.

10.3 Menene zai faru idan aka wuce ƙayyadaddun reflow na 260°C na tsawon dakika 10?

Exceeding the recommended thermal profile can lead to various failures: delamination of the epoxy package, cracking of the silicon die or substrate, degradation of the phosphor (if present), or failure of the internal gold wire bonds. This is likely to cause immediate failure (no light output) or significantly reduce long-term reliability.

11. Practical Application Cases

Scenario: Multi-function status indicator light for a network router.A single LTST-C19FD1WT can replace three separate LEDs, used to indicate power (steady orange), network activity (flashing green), and error status (flashing blue). The GPIO pins of the microcontroller, each connected in series with a current-limiting resistor calculated as in Section 8.1, independently control each color. The 130-degree wide viewing angle ensures the indicator is visible from any position in the room. Its ultra-thin profile allows it to be mounted behind slim panel bezels. By using PWM on the microcontroller, the brightness of each color can be adjusted for optimal visibility under different ambient lighting conditions.

12. Introduction to Working Principles

Light-emitting diode (LED) is a semiconductor device that emits light through electroluminescence. When a forward voltage is applied across the p-n junction, electrons from the n-type material recombine with holes from the p-type material, releasing energy in the form of photons. The wavelength (color) of the emitted light is determined by the energy band gap of the semiconductor material. The LTST-C19FD1WT employs two material systems: indium gallium nitride (InGaN) for the blue and green chips, which has a wider band gap; and aluminum indium gallium phosphide (AlInGaP) for the orange chip, which has a narrower band gap, corresponding to longer wavelengths (red/orange). A diffused white lens encapsulates the chips, providing mechanical protection, shaping the light output beam, and mixing colors when multiple chips are activated.

13. Technology Trends

LTST-C19FD1WT gibi SMD LED'lerin gelişimi, optoelektroniğin daha geniş trendlerini takip eder: artan entegrasyon, küçülme ve verimlilik artışı. Gelecek iterasyonlar daha ince paketleme, daha yüksek ışık verimliliği (watt başına daha fazla ışık çıkışı) ve karışık beyaz ışık uygulamaları için geliştirilmiş renksel geriverim indeksi (CRI) özelliklerine sahip olabilir. Bir diğer trend, üst düzey ekran uygulamaları için daha tutarlı renk ve parlaklık sağlamak amacıyla daha sıkı binleme toleranslarıdır. Gelişmiş düşük güçlü dijital mantıkla (örneğin 1.8V veya 3.3V sistemler) uyumluluk için daha düşük voltajlı çalışmaya yönelik itici güç, süregelen bir gelişim alanıdır.