LTST-C171TBKT-5A SMD Chip Blue LED Datasheet - 0.8mm Ultra-Thin Height - 2.8V-3.05V Forward Voltage - 76mW Power Dissipation - Technical Documentation

1. Uhakiki wa Bidhaa

This document provides the complete technical specifications for the LTST-C171TBKT-5A, a Surface Mount Device (SMD) Light Emitting Diode (LED) chip. This product belongs to an ultra-thin, high-brightness blue LED series specifically designed for modern electronic assembly processes. The primary application of this component is as an indicator light, backlight, or status display, widely used in compact electronic devices where space and height are critical limiting factors.

The core advantage of this LED lies in its extremely small form factor, with a height of only 0.80 millimeters. This makes it suitable for applications in ultra-thin consumer electronics, portable devices, and high-density PCBs. Its manufacturing process is compatible with automatic pick-and-place equipment, ensuring efficiency in large-scale assembly. The device also complies with the RoHS (Restriction of Hazardous Substances) directive, classifying it as a green product suitable for global markets with strict environmental regulations.

Target markets include manufacturers of office automation equipment, communication devices, home appliances, and various industrial control panels. Its compatibility with infrared (IR) and vapor phase reflow soldering processes makes it suitable for standard and lead-free (Pb-free) assembly lines used in mass production.

2. In-depth Analysis of Technical Parameters

This section provides an objective and detailed interpretation of the key technical parameters specified in the datasheet.

2.1 Absolute Maximum Ratings

Absolute maximum ratings define the stress limits that may cause permanent damage to the device. These are not normal operating conditions.

• Power Dissipation (Pd):76 mW. This is the maximum power the LED can dissipate as heat at an ambient temperature (Ta) of 25°C. Exceeding this limit may cause thermal damage to the semiconductor junction.
• DC Forward Current (IF):20 mA. This is the recommended maximum continuous forward current to ensure long-term reliable operation.
• Peak Forward Current:100 mA. This rating applies only under pulsed conditions with an extremely low duty cycle (1/10) and very short pulse width (0.1ms). It is associated with brief, high-intensity flashes and is not suitable for constant illumination.
• Reverse Voltage (VR):5 V. Applying a reverse bias voltage exceeding this value may cause the PN junction breakdown and failure of the LED.
• Operating Temperature Range:-20°C to +80°C. Ensures the device operates normally within this ambient temperature range.
• Storage Temperature Range:-30°C to +100°C. The device will not experience performance degradation when stored within this range.
• Soldering Temperature Tolerance:The datasheet specifies conditions for wave soldering (260°C, 5 seconds), infrared reflow soldering (260°C, 5 seconds), and vapor phase reflow soldering (215°C, 3 minutes). These are crucial for PCB assembly without damaging the LED package.

2.2 Electrical and Optical Characteristics

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

• Luminous Intensity (Iv):At a forward current (IF) of 5 mA, the typical value is 15.0 mcd. The minimum guaranteed value is 11.2 mcd. This is the perceived brightness of the LED measured using a filter approximating the CIE photopic response curve.
• Forward Voltage (VF):At IF=5mA, the typical value is 2.80 V, and the maximum value is 3.05 V. This is the voltage drop across the LED when it is conducting current. It is a key parameter for designing current-limiting circuits.
• Viewing Angle (2θ1/2):Thamani ya kawaida ni digrii 130. Pembe hii pana ya mtazamo inaonyesha LED hutoa mwanga kwenye safu pana ya pembe ya koni, na kuifanya inafaa kwa matumizi ambayo mwonekano kutoka pembe nyingi ni muhimu.
• Urefu wa wimbi la upeo wa utoaji (λP):468 nm. Huu ndio urefu wa wimbi ambao pato la nguvu ya wigo ni la juu zaidi.
• Urefu wa wimbi kuu (λd):Ni 470.0 nm hadi 475.0 nm wakati IF=5mA. Hii imetokana na chati ya CIE chromaticity, na inawakilisha urefu wa wimbi mmoja unaoelezea vyema zaidi rangi ya mwanga inayohisiwa na jicho la mwanadamu. Kwa vipimo vya rangi, ni parameta inayohusika zaidi kuliko urefu wa wimbi la upeo.
• Upana wa nusu ya mstari wa wigo (Δλ):Thamani ya kawaida ni 25 nm. Hii hupima upana wa ukanda wa wigo wa utoaji kwenye nusu ya kiwango cha juu cha nguvu yake. Thamani ya 25 nm ni sifa ya LED ya bluu ya InGaN.
• Mkondo wa nyuma (IR):At VR=5V, the maximum value is 10 μA. This is the small leakage current that flows when the LED is reverse-biased within its maximum ratings.

2.3 Thermal Characteristics

Thermal performance is indicated by a derating factor. When the ambient temperature exceeds 50°C, the DC forward current must be linearly reduced by 0.25 mA for every 1°C increase. This is crucial for ensuring reliability at higher operating temperatures. For example, at the maximum operating temperature of 80°C, the maximum allowable continuous current is: 20 mA - [0.25 mA/°C * (80°C - 50°C)] = 20 mA - 7.5 mA = 12.5 mA.

3. Maelezo ya Mfumo wa Kugawa Daraja

To manage natural variations in the semiconductor manufacturing process, LEDs are sorted into different performance bins. This allows designers to select components with tightly controlled characteristics for their applications.

3.1 Kugawa Daraja kwa Voltage ya Mbele

Based on the forward voltage (VF) measured at 5 mA, LEDs are divided into four bins.

• Kikundi 1: 2.65 V - 2.75 V
• Kikundi 2: 2.75 V - 2.85 V
• Kikundi 3: 2.85 V - 2.95 V
• Kikundi 4: 2.95 V - 3.05 V

Toleransi ndani ya kila kikundi ni ±0.1 V. Kutumia LED kutoka kikundi sawa cha voltage katika mzunguko wa sambamba husaidia kufikia usambazaji wa sasa na mwangaza sawa zaidi.

3.2 Kugawa Daraja kwa Nguvu ya Mwanga

Kulingana na nguvu ya mwanga (Iv) kwenye 5 mA, LED zimegawanywa katika vikundi sita, kuanzia L1 (chini kabisa) hadi N2 (juu kabisa).

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

Kila kiwango cha nguvu kina uvumilivu wa ±15%. Uainishaji huu ni muhimu sana kwa matumizi ambayo yanahitaji usawa wa mwangaza kati ya viashiria vingi vya taa.

3.3 Kugawa Daraja kwa Wavelength Kuu

Kwa aina hii maalum, vifaa vyote viko katika kiwango kimoja cha wavelength kuu: AD, kuanzia 470.0 nm hadi 475.0 nm. Kiwango hiki kina uvumilivu wa ±1 nm, na kuhakikisha utoaji wa mwanga wa bluu unaolingana sana.

4. Performance Curve Analysis

Ingawa maagizo yanataja curves maalum za picha (Kielelezo 1, Kielelezo 6), tabia yake ya kawaida inaweza kuelezewa kulingana na kanuni za kawaida za fizikia za LED na vigezo vilivyotolewa.

4.1 Current vs. Voltage (I-V) Characteristics

Mkunjo wa I-V wa LED ya bluu ya InGaN kama hii sio wa mstari ulionyooka. Chini ya kizingiti cha voltage ya mbele (takriban 2.6-2.7V), hakuna sasa unaopita kwa karibu. Voltage inapokaribia na kuzidi thamani ya kawaida ya VF ya 2.8V, sasa huongezeka kwa kasi. Ndio maana LED lazima iendeshwe na chanzo cha kikomo cha sasa, sio chanzo cha voltage mara kwa mara. Tofauti ndogo za VF kati ya vifaa binafsi (kama inavyoonyeshwa kwenye kiwango) husababishwa na tofauti ndogo katika safu za nje za semiconductor na usindikaji wa chip.

4.2 Luminous Intensity vs. Forward Current

Katika safu kubwa, pato la mwanga (nguvu ya mwanga) takriban ni sawia na sasa wa mbele. Hata hivyo, kwa sasa wa juu sana, ufanisi hupungua kwa sababu ya ongezeko la joto (athari ya kupungua kwa ufanisi). Sasa wa kawaida wa DC wa 20 mA umechaguliwa kwa usawa kati ya mwangaza mzuri na uimara wa muda mrefu.

4.3 Spectral Distribution

Mkunjo wa pato la wigo utaonyesha kilele kikuu karibu na 468 nm (bluu). Upana wa nusu wa 25 nm unaonyesha usafi wa wigo. Katika pato la LED ya bluu ya InGaN iliyotengenezwa vizuri, haitakuwa na kilele cha pili kinachotambulika. Urefu wa wigo mkuu wa 470-475 nm huweka rangi ya LED hii katika eneo la kawaida la bluu.

4.4 Temperature Dependence

Kadiri joto la kiungo linavyopanda, voltage ya mbele kwa kawaida hupungua kidogo (kisababishi cha joto hasi), wakati ukubwa wa mwanga na urefu wa wimbi mkuu wanaweza kubadilika. Vipimo vya kupunguza nguvu vinashughulikia moja kwa moja hitaji la kupunguza mkondo katika mazingira ya joto ili kudhibiti joto la kiungo na kudumisha utendakazi na maisha ya huduma.

5. Mechanical and Packaging Information

5.1 Package Dimensions

LED hii inatumia ufungaji wa kawaida wa EIA. Sifa yake muhimu ya mitambo ni umbo lake nyembamba sana, na urefu (H) wa milimita 0.80. Vipimo vyote vingine (urefu, upana, umbali wa pini) vinakubaliana na eneo la kawaida la kukaa la aina hii ya ufungaji, na kuhakikisha utangamano na vifaa vya usanikishaji otomatiki na muundo wa kawaida wa pedi za PCB. Nyenzo ya lenzi imebainishwa kuwa "Water Clear", ambayo ni epoksi isiyo na rangi na wazi ambayo haitawanyiki mwanga, na hivyo kutoa mwanga mkali na uliolengwa kutoka kwa chip.

5.2 Polarity Identification

The datasheet includes a package outline drawing that clearly indicates the cathode and anode terminals. Typically, the cathode is marked by a notch, a green dot, or a shorter lead/tab on the package body. Correct polarity must be observed during PCB assembly, as applying reverse bias may damage the device.

5.3 Recommended Pad Layout

A recommended land pattern (pad dimensions and spacing) is provided to ensure good solder joint formation, mechanical stability, and thermal relief during reflow. Adhering to this guideline is crucial for achieving high assembly yield and reliability.

6. Soldering and Assembly Guide

6.1 Reflow Soldering Profile

The datasheet provides two recommended infrared (IR) reflow profiles: one for conventional (tin-lead) soldering processes and one for lead-free processes. The key parameters are:

• Upashaji joto kabla ya kuyeyusha (Preheating):Kupanda kwa joto hatua kwa hatua ili kuamilisha flux na kupunguza mshtuko wa joto kwa kiwango cha juu.
• Muda wa kutosheleza/Upashaji joto kabla ya kuyeyusha (Soak/Preheat Time):Si zaidi ya sekunde 120, ili kuzuia oksidisho kupita kiasi.
• Kiwango cha juu cha joto (Peak Temperature):Si zaidi ya 260°C. LED inaweza tu kustahimili joto hili kwa muda mfupi sana.
• Muda wa juu ya mstari wa kioevu (Time Above Liquidus - TAL):For lead-free processes, the profile must ensure the solder paste melts for the correct duration to form reliable solder joints, typically referencing the time between specific temperature lines (e.g., 217°C for SnAgCu solder).

Strict adherence to these profiles is critical. Excessive time or temperature during reflow can damage the LED's epoxy lens, degrade semiconductor chip performance, or weaken internal wire bonds.

6.2 Storage Conditions

LEDs are moisture-sensitive devices. If removed from the original moisture barrier bag, they must be used within 672 hours (28 days) or baked prior to soldering to remove absorbed moisture. Extended storage outside the original bag requires a controlled environment: a sealed container with desiccant or a nitrogen-purged dry box. Failure to follow these procedures may lead to "popcorning" during reflow, where internal vapor pressure causes package cracking.

6.3 Cleaning

If post-solder cleaning is necessary, only specified solvents should be used. The datasheet recommends immersion in ethanol or isopropyl alcohol at room temperature for no more than one minute. Using harsh or unspecified chemicals may cloud, crack, or otherwise damage the LED's epoxy lens.

7. Packaging and Ordering Information

7.1 Tape and Reel Specifications

LEDs are supplied in industry-standard embossed carrier tape, wound on 7-inch (178 mm) diameter reels. This packaging is compatible with high-speed automatic placement machines.

• Quantity per reel:3000 pieces.
• Minimum order quantity:Minimum order quantity is 500 pieces.
• Cover tape:Empty component pockets are sealed with top cover tape.
• Missing Component:According to quality standards, the maximum number of consecutive missing components in the tape is two.
• Standard:Packaging complies with ANSI/EIA 481-1-A-1994 specification.

8. Application Recommendations

8.1 Mandhari ya Kawaida ya Utumizi

• Viasho vya Kiashiria cha Hali:Viasho vya kuwasha umeme, kusubiri, kuchaji au kosa katika vifaa vya matumizi ya kielektroniki, vya nyumbani na vya mtandao.
• Mwanga wa Nyuma:Inatumika kwa skrini ndogo za LCD, kibodi au swichi za filamu nyembamba katika vifaa vya kifupi.
• Mwanga wa Paneli:Inatumika kwa taa za dashibodi, paneli za udhibiti na vifaa vya kiolesura cha binadamu na mashine vya viwanda.
• Mwanga wa Mapambo:Mwanga wa msisitizo katika nafasi nyembamba ambapo umbo la kifupi sana ni muhimu.

8.2 Mambo ya Kuzingatia katika Ubunifu wa Saketi

Kiini: LED ni kifaa kinachoendeshwa na mkondo.Kanuni muhimu zaidi ya ubunifu ni kudhibiti mkondo wa mwelekeo sahihi.

• Upinzani wa kuzuia mkondo (Mfano wa Sakiti A):Wakati LED nyingi zimeunganishwa sambamba, ni lazimakwa kilaLED kutumia upinzani wa kuzuia mkondo wa kipekee uliounganishwa mfululizo. Hii ni kwa sababu voltage ya mwelekeo sahihi (VF) inaweza kutofautiana kidogo kati ya LED tofauti (kama ilivyofafanuliwa na upangaji). Bila upinzani wa kipekee, LED zilizo na VF ya chini zitachukua mkondo zaidi kwa uwiano usiofaa, na kusababisha mwangaza usio sawa na mzigo kupita kiasi katika vitengo hivyo. Thamani ya upinzani inahesabiwa kwa kutumia Sheria ya Ohm: R = (Voltage ya usambazaji - VF ya LED) / Mkondo unaotarajiwa.
• Unganisho sambamba bila upinzani (Mfano wa Sakiti B):Usanidi huuHaupendekezwi, kwa sababu tofauti za asili za Tabia ya I-V zitasababisha usawa wa mwanga na utendakazi usioaminika.
• Unganisho Mfululizo:Kuunganisha LED mfululizo kuhakikisha zote hupitia mkondo sawa. Upinzani wa kikomo wa mkondo unaweza kutumiwa kwa tawi zima la mfululizo. Voltage ya usambazaji lazima iwe ya kutosha kushinda jumla ya voltages mbele ya LED zote kwenye tawi.

8.3 Ulinzi dhidi ya Utoaji Umeme wa Tuli (ESD)

LED ni nyeti kwa utoaji umeme tuli (ESD). Tahadhari lazima zichukuliwe wakati wa uendeshaji na usanikishaji:

• Operatörler topraklama bilekliği veya antistatik eldiven takmalıdır.
• Tüm çalışma istasyonları, aletler ve ekipmanlar uygun şekilde topraklanmalıdır.
• LED'leri ESD güvenli ambalajlarda depolayın ve taşıyın.

9. Ulinganishi wa Kiufundi na Tofauti

Genel veya daha eski mavi LED çiplerine kıyasla, bu LED'in ana farklılaştırıcı faktörleri şunlardır:

• Ultra ince form faktörü (0.8mm yükseklik):Inaweza kubuni bidhaa za mwisho nyembamba zaidi, ambayo ni mahitaji muhimu ya simu janja za kisasa, kompyuta kibao, na kompyuta nyembamba sana.
• Uwekaji wa kawaida wa EIA:Kuhakikisha utangamano na mstari wa usanikishaji wa kiotomatiki na eneo la kukaa la maktaba ya PCB iliyopo, na kupunguza wakati na hatari ya kubuni.
• Utangamano wa mchakato wa ununuzi mara mbili:Imethibitishwa kupitia michakato ya kawaida (SnPb) na isiyo na risasi (SnAgCu) ya kurudisha, na kufanya muundo uendane na kanuni za kimataifa za mazingira, na kuwa na mtazamo wa mbele.
• Mgawanyiko kamili:Inawapa wabunifu uwezo wa kuchagua vipengele vilivyo na udhibiti mkali wa mwangaza (Iv) na voltage ya mbele (VF), na hivyo kupata utendakazi thabiti zaidi katika bidhaa zinazozalishwa kwa wingi.
• Chaguo la mwangaza wa juu:Inatoa chaguo la hadi kiwango cha N2 (45.0 mcd), ikitoa urahisi kwa matumizi yanayohitaji kuonekana zaidi.

10. Maswali Yanayoulizwa Mara kwa Mara (Kulingana na Vigezo vya Kiufundi)

10.1 Je, naweza kutumia chanzo cha umeme cha mantiki ya 3.3V au 5V kuendesha LED hii moja kwa moja?

Hapana, haiwezi kuendeshwa moja kwa moja.Lazima utumie kipingamizi cha mfululizo cha kudhibiti mkondo. Kwa mfano, ukichukua chanzo cha 3.3V na lengo la mkondo wa 5mA, ukichukua thamani ya kawaida ya VF ya 2.8V: R = (3.3V - 2.8V) / 0.005A = ohms 100. Bila kipingamizi, LED itajaribu kuchukua mkondo mwingi kupita kiasi, ukizuiliwa tu na chanzo na upinzani wa ndani wa LED, na kwa uwezekano mkubwa itaidhuru.

10.2 Kwa nini kiwango cha kilele cha sasa (100mA) kiko juu zaidi kuliko kiwango cha DC (20mA)?

Ukadiriaji wa mkondo wa kilele unatumika kwa misukumu mifupi sana (0.1ms) yenye uwiano wa kazi mdogo (10%). Chini ya hali hizi, kiungo cha semiconductor hakina muda wa kupata joto sana. Kwa uendeshaji endelevu (DC), mkusanyiko wa joto ndio kikwazo, kwa hivyo ukadiriaji wa chini wa 20mA ni kuhakikisha uimara wa muda mrefu na kuzuia kukosa udhibiti wa joto.

10.3 Kuna tofauti gani kati ya urefu wa wimbi la kilele na urefu wa wimbi kuu?

Peak Wavelength (λP)It is the actual highest point (468 nm) on the spectral output curve.Dominant Wavelength (λd)It is a calculated value (470-475 nm) corresponding to the color perceived by the human eye on the CIE chromaticity diagram. For color specification in applications, dominant wavelength is the more relevant parameter.

10.4 The LED worked normally after soldering but later failed. What are the possible reasons?

Common causes include: ESD damage during handling, thermal overstress during soldering (exceeding the time/temperature profile), incorrect polarity on the PCB, excessive drive current due to a missing or miscalculated current-limiting resistor, or moisture-induced damage (popcorn effect) from improper storage of moisture-sensitive devices.

11. Practical Design Case Studies

Mandhari:Unda paneli ya udhibiti yenye taa za mwongozo nne za hali ya bluu. Paneli hiyo inaendeshwa na reli ya umeme ya 5V. Mwangaza sawa ni muhimu sana kwa uzuri.

1. Uchaguzi wa LED:Chagua LED kutoka kwa kiwango sawa cha nguvu ya mwanga (mfano, zote kutoka kiwango cha M1: 18.0-22.4 mcd) na kiwango sawa cha voltage ya mbele (mfano, zote kutoka kiwango cha 2: 2.75-2.85V) ili kupunguza tofauti za asili.
2. Uundaji wa Saketi:Tumia muundo wa saketi A. Unganisha kila LED kwa sambamba na upinzani wake wa mfululizo. Kwa sasa lengo la 5mA na thamani ya VF ya kihafidhina ya 2.85V (kiwango cha juu cha kiwango cha 2), hesabu R = (5V - 2.85V) / 0.005A = 430 ohms. Thamani ya kawaida iliyo karibu zaidi ni 430Ω au 470Ω.
3. Mpangilio wa PCB:Follow the pad dimensions recommended in the datasheet. Ensure correct polarity alignment based on the package marking.
4. Assembly:Use the recommended lead-free reflow profile. Ensure LEDs are used within 672 hours after opening the moisture barrier bag or undergo proper baking.
5. Result:Four indicator lights with consistent brightness and color, reliable long-term operation, and high manufacturing yield.

12. Working Principle

The LTST-C171TBKT-5A is a semiconductor device based on indium gallium nitride (InGaN) material. When a forward bias voltage exceeding the junction's built-in potential is applied, electrons from the n-type region and holes from the p-type region are injected into the active region. When these carriers recombine, they release energy in the form of photons (light). The specific composition of the InGaN alloy in the active layer determines the bandgap energy, which in turn determines the wavelength (color) of the emitted light. For this device, the bandgap is engineered to produce photons in the blue spectrum (approximately 470 nm). A transparent epoxy lens encapsulates and protects the semiconductor chip, provides mechanical stability, and shapes the light output beam.

13. Technology Trends

The development of such SMD LEDs follows several clear industry trends:

• Miniaturization:Continuously reducing package size (footprint and height) to enable thinner and more compact electronic products.
• Efficiency Enhancement:Continuously improving Internal Quantum Efficiency (IQE) and light extraction efficiency to deliver higher luminous intensity at the same or lower drive current, thereby improving battery life in portable devices.
• Standardization and Automation:Kufuata umbo la kawaida la ufungaji na muundo wa reeli ya mkanda ili kurahisisha michakato ya usanisi otomatiki kwa kiwango kikubwa ulimwenguni.
• Uzingatiaji wa mazingira:Kuondoa vitu hatari (RoHS, REACH) na uwezo wa kuchanganyika na michakato ya usanisi isiyo na risasi (Pb-free) sasa ni mahitaji ya kawaida.
• Uthabiti wa rangi:Kwa matumizi ambayo usawa wa kuona ni muhimu sana (kama vile skrini na ishara), inahitaji uvumilivu mkali zaidi wa kiwango cha mwanga, voltage ya mbele, na kuratibu za rangi.