LTST-S326TBKSKT Dual-Color Side-Emitting SMD LED Datasheet - Blue and Yellow - 20mA/30mA - Technical Documentation

1. Product Overview

This document details the technical specifications of a dual-color side-view Surface-Mount Device (SMD) Light-Emitting Diode (LED). The device integrates two independent semiconductor chips within a single package: one emitting in the blue spectrum and the other in the yellow spectrum. This configuration is specifically designed for space-constrained applications requiring observation from the component's side, making it suitable for compact multi-state indicators, backlighting, or decorative lighting.

The core advantages of this product include compliance with the RoHS (Restriction of Hazardous Substances) directive, making it suitable for modern electronics manufacturing. It utilizes a tin-plated lead frame to enhance solderability and corrosion resistance. Components are packaged on industry-standard 8mm tape reels for compatibility with high-speed automated pick-and-place assembly equipment. Furthermore, its design can withstand the standard infrared (IR) reflow soldering processes commonly used in Surface-Mount Technology (SMT) production lines.

2. Cikakken bayani game da sigogi na fasaha

2.1 Absolute Maximum Ratings

These ratings define the limits that may cause permanent damage to the device. Operation under these conditions is not guaranteed and should be avoided to ensure reliable performance.

• Power Dissipation (Pd):At an ambient temperature (Ta) of 25°C, the maximum allowable power dissipation is 76 mW for the blue chip and 75 mW for the yellow chip. Exceeding this limit risks thermal damage.
• Forward Current:The maximum continuous DC forward current (IF) is 20 mA for the blue chip and 30 mA for the yellow chip. Higher peak forward currents are permitted only under pulse conditions (1/10 duty cycle, 0.1ms pulse width): 100 mA for blue and 80 mA for yellow, to prevent overheating.
• Thermal Derating:When the ambient temperature exceeds 25°C, the maximum DC forward current must be linearly reduced at a derating rate of 0.25 mA/°C for the blue chip and 0.4 mA/°C for the yellow chip. This is crucial for applications in high-temperature environments.
• Reverse Voltage (VR):The maximum allowable reverse voltage for both chips is 5V. Applying a higher reverse voltage may cause junction breakdown. Please note that continuous operation under this reverse voltage is prohibited.
• Temperature Range:The operating temperature rating for the device ranges from -20°C to +80°C. The storage temperature should be between -30°C and +100°C.
• Soldering Heat Limit:This component can withstand wave or infrared reflow soldering with a peak temperature of 260°C for up to 5 seconds, and vapor phase soldering at 215°C for up to 3 minutes.

2.2 Electrical and Optical Characteristics

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

• Luminous Intensity (Iv):This is a measure of the perceived power of light emitted in a specific direction. For both colors, the minimum intensity is 28.0 millicandelas (mcd), the typical value is 45.0 mcd (specified for blue only), and the maximum is 180.0 mcd. The actual shipped intensity is determined by a binning system.
• Viewing Angle (2θ1/2):The full angle at which the luminous intensity drops to half of its axial (center) value is 130 degrees for both colors, indicating the typical wide viewing pattern of side-emitting LEDs.
• Wavelength:The typical peak emission wavelength (λP) for the blue chip is 468 nm, and the dominant wavelength (λd) is 470 nm. For the yellow chip, the typical peak wavelength is 592 nm, and the dominant wavelength is 590 nm. The spectral line half-width (Δλ) is 25 nm for blue and 17 nm for yellow, describing the spectral purity.
• Forward Voltage (VF):The voltage drop across the LED at an operating current of 20mA, with a typical value of 3.4V (max 3.8V) for blue and 2.0V (max 2.4V) for yellow. This parameter is crucial for driver circuit design and power supply selection.
• Reverse Current (IR):The maximum leakage current when a 5V reverse voltage is applied is 10 μA for both chips.
• Capacitance (C):The typical junction capacitance of the yellow chip is 40 pF at 0V bias and a measurement frequency of 1 MHz.

3. Bayani game da tsarin rarrabawa

To ensure production consistency, LEDs are binned according to performance. This device uses a luminous intensity-based binning system.

For blue and yellow chips, the luminous intensity at 20mA current is divided into four bins:

• N grade:Intensity range from 28.0 mcd to 45.0 mcd.
• P grade:Intensity range from 45.0 mcd to 71.0 mcd.
• Q grade:Intensity range from 71.0 mcd to 112.0 mcd.
• R grade:Intensity range from 112.0 mcd to 180.0 mcd.

The boundaries for each intensity bin allow a tolerance of +/-15%. This system enables designers to select components based on the specific brightness requirements of their application, ensuring visual consistency in end products that use multiple LEDs.

4. Performance Curve Analysis

While specific graphical data (e.g., Figure 1, Figure 6) are referenced in the datasheet, the typical curves for such devices provide key insights:

• I-V (Current-Voltage) Curve:This curve shows the relationship between forward voltage (VF) and forward current (IF). It is nonlinear, featuring a characteristic "knee" voltage (typically around the nominal VF value), beyond which current increases rapidly with a small increase in voltage. This highlights why LEDs must be driven by a current-limited source, not a constant voltage source.
• Luminous Intensity vs. Forward Current:Intensity generally increases with current, but the relationship may not be perfectly linear, especially at higher currents where efficiency can drop due to heating.
• Luminous Intensity vs. Ambient Temperature:The light output of an LED decreases as its junction temperature increases. Understanding this derating is crucial for applications operating over a wide temperature range.
• Spectral Distribution:The referenced graph will show relative radiant power versus wavelength, highlighting the peak (λP) and spectral width (Δλ).

5. Mechanical and Packaging Information

5.1 Package Dimensions and Pin Assignment

This device complies with the EIA standard package outline. Physical dimensions are provided in the datasheet drawings, all units are in millimeters, with a general tolerance of ±0.10 mm unless otherwise specified.

Pin Assignment:The dual-color LED has a specific pin arrangement to independently control each chip. For model LTST-S326TBKSKT:

• Cathode 1 (C1):Connected to the yellow AlInGaP chip.
• Cathode 2 (C2):Connected to the blue InGaN chip.
• The anode is common to both chips.

During PCB layout and assembly, correct polarity identification is crucial to ensure proper functionality.

5.2 Recommended Land Pattern

Takardar ƙayyadaddun bayanai ta ƙunshi ƙirar ƙafar gwangwani na PCB da aka ba da shawara. Yin bin waɗannan girmansa yana tabbatar da samuwar ingantacciyar haɗin gwangwani, kwanciyar hankali na injina da sakin zafi yayin aikin sake kwarara. Yin amfani da ƙafar gwangwani ƙanƙanta da yawa na iya haifar da haɗin gwangwani mara ƙarfi, yayin da ƙafar gwangwani girma da yawa na iya haifar da tashin dutse (ɗayan ɓangaren kayan yana ɗagawa) ko gada.

6. Soldering and Assembly Guide

6.1 Reflow Soldering Profile

An ba da lanƙwanin sake kwarara na infrared (IR) guda biyu da aka ba da shawara: ɗaya don tsarin haɗin gwangwani na al'ada (tin-lead) ɗayan kuma don tsarin haɗin gwangwani mara gubar. Lanƙwanin mara gubar an tsara shi musamman don amfani da man haɗin gwangwani Sn-Ag-Cu (SAC). Muhimman sigogi a cikin waɗannan lanƙwanai sun haɗa da:

• Yankin dumama / dumama:A hankali tada zafin jiki don kunna taimakon solder da rage girgizar zafi.
• Kwararar yankin:Zafin jiki ya wuce narkakkar solder don samar da haɗin solder. Kololuwar zafin bai kamata ya wuce 260°C ba, kuma lokacin da ya wuce layin ruwa (TAL) dole ne a sarrafa shi.
• Yankin sanyaya:Sarrafa sanyaya ya sa haɗin solder ya daskare.

6.2 Cleaning

Idan ana buƙatar tsaftacewa bayan solder, ya kamata a yi amfani da kawai ƙayyadaddun kaushi. Specification yana ba da shawarar nutsar da LED a cikin ethanol ko isopropyl alcohol a zafin daki na tsawon minti ɗaya kawai. Yin amfani da wani kaushi ko mai ƙarfi wanda ba a ƙayyade ba na iya lalata kayan LED encapsulation, haifar da canza launi, fashewa, ko rarrabuwa.

6.3 Storage Conditions

For long-term storage, LEDs should be kept in their original moisture barrier packaging. If removed, they are sensitive to moisture absorption (MSL - Moisture Sensitivity Level). The datasheet recommends that components removed from the original packaging should be reflow soldered within one week. For long-term storage outside the original barrier bag, they should be stored in a sealed container with desiccant or in a nitrogen environment. If stored unpackaged for more than one week, baking before soldering (e.g., 24 hours at 60°C) is recommended to drive out absorbed moisture and prevent "popcorn" damage during reflow.

7. Bayanin Tufafi da Oda

The device is supplied on tape and reel suitable for automated assembly.

• Tape width:8 mm.
• Reel diameter:Inci 7 (milimita 178).
• Yawan kowane nadi:Guda 3000.
• Mafi ƙarancin adadin oda (MOQ):Sauran adadin ya fara daga guda 500.
• Ma'aunin tattarawa:Ya bi ka'idojin ANSI/EIA 481-1-A-1994. An rufe guraben da ke cikin teep ɗin da murfin teep. Matsakaicin adadin abubuwan da suka ɓace a jere shine biyu.

8. Shawarar Aikace-aikace

8.1 Yanayin Aikace-aikace na Al'ada

This bi-color side-emitting LED is ideal for applications with limited space where indicator viewing from the edge of the PCB or component is required. Common uses include:

• Status Indicators:For consumer electronics, networking equipment, or industrial control devices, where different colors can indicate power (yellow), activity (blue), or fault status.
• Backlighting:For edge-lit panels, keyboards, or small displays, where side emission offers an advantage.
• Decorative Lighting:For compact devices requiring multi-color effects.

8.2 Abubuwan Lura na Zane

• Drive Circuit:LEDs are current-driven devices. To ensure uniform brightness, especially when multiple LEDs are connected in parallel, a current-limiting resistor must be connected in series with each LED. It is not recommended to drive multiple LEDs directly in parallel from a voltage source (without individual resistors) due to variations in forward voltage (VF) among individual LEDs, which can lead to significant differences in brightness and potential overcurrent in some devices.
• Thermal Management:Although power consumption is low, a proper PCB layout with sufficient copper area helps dissipate heat, especially under high ambient temperatures or when driven at maximum current. This helps maintain light output and lifespan.
• Electrostatic Discharge (ESD) Protection:LED yana da hankali ga ESD. Matakan kariya na aiki ya haɗa da amfani da bandeji na wuyan ƙasa, katifa mai hana tashin hankali, da injin ion a yankin taro. Dole ne kayan aiki da tashoshin aiki su kasance da ƙasa daidai.

9. Kwatancen fasaha da bambance-bambance

Mahimmancin siffa ta bambance-bambance na kayan aikin shine ikonsa na launi biyu a cikin fakitin SMD mai haskaka gefe ɗaya da ƙayyadaddun ƙimar aikin sa. Idan aka kwatanta da LED mai launi ɗaya, yana adana sararin allon kuma yana sauƙaƙa haɗa alamar launi biyu. Siffar haskaka gefen ta bambanta shi da LED mai haskaka saman, yana dacewa da ƙayyadaddun ƙirar injina. Dacewarsa da haɗawa ta atomatik da da'irori na dawowa na daidaitaccen yanayin ya sa ya dace da hanyoyin ƙera masu yawa na zamani. Cikakken tsarin rarrabuwa yana ba da matakin daidaiton haske wanda ya fi na kayan gama gari marasa rarrabuwa ko fadi.

10. Tambayoyin da ake yawan yi (bisa sigogin fasaha)

Tambaya: Shin zan iya tuƙi LED ɗin shuɗi da rawaya tare da matsakaicin igiyar ruwa DC?
Amsa: Ba lallai ba ne. Matsakaicin ƙayyadaddun ƙididdiga ya ƙayyade yawan wutar lantarki na kowane guntu. Lokacin tuƙa guntu biyu tare da 20mA (shuɗi) da 30mA (rawaya), dole ne a duba jimillar yawan wutar lantarki daidai da iyakokin zafi, musamman idan aka yi la'akari da yanayin raba fakitin. Dole ne a yi amfani da raguwa a yanayin zafi na muhalli mai girma.

Tambaya: Me yasa kowane LED yana buƙatar resistor a jere, ko da a cikin jeri na layi daya?
A: LED forward voltage (VF) has manufacturing tolerances. Without individual resistors, LEDs with slightly lower VF will draw disproportionately more current, becoming brighter and potentially overheating, while LEDs with higher VF will be dimmer. The resistor acts as a simple and effective current regulator for each LED.

Q: What does "side-view" mean for viewing angle?
A: "Side-view" LEDs emit light primarily from the side of the package, perpendicular to the mounting plane. The 130-degree viewing angle is measured from this primary emission axis. This contrasts with "top-view" LEDs, which emit light upward from the top of the package.

Q: How to interpret the binning code when ordering?
A: The binning code (N, P, Q, R) specifies the guaranteed minimum and maximum luminous intensity range for that batch of LEDs. Designers should select a bin that meets their minimum brightness requirement while considering cost, as higher brightness bins (e.g., R bin) may be more expensive.

11. Misalan amfani na ainihi

Scenario: Dual-State Indicator for a Portable Device
A designer is creating a compact handheld sensor. They need a single, small indicator to show both "Standby" and "Active/Transmitting" states. They selected this bi-color LED.
Implementation Plan:The LED is placed at the edge of the main PCB, with its light-emitting surface facing a small light guide that directs the light to the exterior of the device. The microcontroller's GPIO pins drive the cathodes (C1 for yellow, C2 for blue) through individual current-limiting resistors (calculated based on the supply voltage and the desired 20mA current). The common anode is connected to the positive supply. The firmware illuminates the yellow LED to indicate standby mode and the blue LED to indicate active mode. The side-emitting characteristic of the LED allows for efficient coupling into the side-entry light guide, creating a clear, professional indicator light within a very limited space.

12. Gabatarwar ka'ida

A Light Emitting Diode (LED) is a semiconductor device that emits light when an electric current passes through it. This phenomenon is called electroluminescence. When a forward voltage is applied, electrons from the n-type semiconductor material recombine with holes from the p-type material within the active region of the chip. This recombination releases energy in the form of photons (light particles). The specific wavelength (color) of the emitted light is determined by the energy bandgap of the semiconductor material used. Blue LED chips are typically made from Indium Gallium Nitride (InGaN), which has a wider bandgap suitable for shorter wavelengths (blue light). Yellow LED chips are typically made from Aluminum Indium Gallium Phosphide (AlInGaP), whose bandgap corresponds to longer wavelengths (yellow/red light). Packaging two chips with a common anode allows for independent control of each color from a single 3-pad SMD component.

13. Development Trends

The field of SMD LEDs continues to evolve. The overall trends observable within the industry provide context for such components, including:

• Improvements in Efficiency and Luminous Efficacy:Continuous advancements in materials science and chip design enable more light output (lumens) per unit of electrical input power (watt).
• Miniaturization:Package sizes continue to shrink (e.g., from 0603 to 0402 to 0201 metric sizes) while maintaining or improving performance, enabling denser electronic products.
• Higher Reliability and Longer Lifespan:Improvements in packaging materials, die-attach methods, and phosphor technology (for white LEDs) enhance device longevity and stability under varying temperatures and over time.
• Advanced Color Mixing and Control:Beyond dual-color, RGB (Red, Green, Blue) and RGBW (RGB + White) LEDs within a single package are now common, often integrating drivers for complex color and dimming control.
• Integration:Trends include built-in current limiting resistors, Zener diodes for ESD protection, and even LEDs with fully integrated IC drivers within the package, simplifying circuit design.

This bi-color side-emitting LED represents a mature and reliable solution for specific spatial and indicator needs within this broader technological context.