LTC-4724JS LED Digital Tube Datasheet - 0.4-inch Character Height - AlInGaP Yellow Light - 2.6V Forward Voltage - 40mW Power Consumption - Chinese Technical Documentation

1. Product Overview

LTC-4724JS ni moduli ya kuonyesha yenye sehemu saba za tarakimu tatu, kompaktiki na yenye utendaji wa hali ya juu, iliyoundwa mahsusi kwa matumizi yanayohitaji usomaji wazi wa nambari. Kazi yake kuu ni kuonyesha kwa urahisi tarakimu tatu (0-9) na nukta ya desimali inayofaa kupitia sehemu huru za LED. Kifaa hiki kimeundwa kwa ajili ya kuunganishwa katika mifumo mbalimbali ya elektroniki, ambapo ufanisi wa nafasi, uwezo wa kusomeka na uaminifu ni mambo muhimu.

Teknolojia yake ya msingi hutumia nyenzo za semiconductor za alumini-indiamu-gali-fosforasi (AlInGaP) kutengeneza chipi za LED. Mfumo huu wa nyenzo unajulikana kwa ufanisi wake wa juu na utendaji bora katika eneo la wigo la mwanga wa manjano hadi nyekundu. Chipi hutengenezwa kwenye msingi wa ga-arsenidi (GaAs) usio na uwazi, ambao husaidia kuelekeza mwanga wa pato mbele moja kwa moja, na hivyo kuongeza mwangaza na tofauti. Kiolezi hiki hutumia jopo la kijivu na alama za sehemu nyeupe, hutoa mandharinyuma yenye tofauti kubwa, na kuboresha uwezo wa kusomeka kwa herufi chini ya hali mbalimbali za mwanga.

Kiolezi hiki hutumia usanidi wa kati ya pamoja wa kusoma kwa nguvu. Muundo huu, ikilinganishwa na njia za kuendesha tuli, hupunguza kwa kiasi kikubwa idadi ya pini zinazohitajika za kuendesha. Badala ya kuhitaji pini maalum kwa kila sehemu ya kila tarakimu, inaunganisha kati ya kila tarakimu pamoja na kudhibiti kwa mpangilio (kusoma kwa nguvu), huku aina ya sehemu (A-G, DP) ya anodi ikishirikiwa kati ya tarakimu zote. Hii inafanya iweze kufaa zaidi kwa mifumo ya kidhibiti-dira iliyo na pini za I/O zilizo na ukomo.

2. In-depth Technical Parameter Analysis

2.1 Photometric and Optical Characteristics

Optical performance is the core of display screen functionality. Key parameters are measured under standardized test conditions, typically at an ambient temperature (Ta) of 25°C.

• Average luminous intensity (I_V):This parameter defines the perceived brightness of a single segment. At a test current (I_F) of 1mA, the typical value is 650 µcd (microcandela), with a minimum guaranteed value of 200 µcd. This wide range indicates the existence of a classification or binning process for luminous intensity, which is common in LED manufacturing to ensure a minimum performance level.
• Peak Emission Wavelength (λ_p):Measured under conditions of I_F=20mA, the typical peak wavelength is 588 nanometers (nm). This places its emitted light strictly within the yellow region of the visible spectrum.
• Dominant Wavelength (λ_d):This value is 587 nm, very close to the peak wavelength. The dominant wavelength is the single wavelength that best represents the perceived color of the light and is crucial for applications with strict color requirements.
• Spectral line half-width (Δλ):A typical value is 15 nm. This parameter indicates the spectral purity or bandwidth of the emitted light. As shown in this example, the relatively narrow half-width is characteristic of AlInGaP LEDs, contributing to saturated, pure yellow light.
• Luminous intensity matching ratio (I_V-m):Uwiano huo umewekwa kwa kiwango cha juu cha 2:1, na unafafanua tofauti ya mwangaza inayoruhusiwa kati ya sehemu tofauti ndani ya skrini moja. Uwiano wa 2:1 unamaanisha kuwa chini ya hali sawa za udhibiti, mwangaza wa sehemu yenye mwangaza zaidi haupaswi kuzidi mara mbili ya mwangaza wa sehemu yenye mwangaza mdogo zaidi, na hivyo kuhakikisha usawa wa muonekano.

Vipimo vyote vya nguvu ya mwanga vinatumia mchanganyiko wa sensor ya mwanga na kichujio kilichosanikishwa ili kukaribia mkunjo wa kiwango cha CIE (Kamati ya Kimataifa ya Mwanga) cha msukumo wa kuona wa mwanga, na kuhakikisha kuwa matokeo ya kipimo yanalingana na mtazamo wa kuona wa binadamu.

2.2 Electrical Characteristics and Absolute Maximum Ratings

Adhering to these limits is crucial for device longevity and preventing catastrophic failure.

• Continuous forward current per segment:At 25°C, the maximum permissible continuous DC current through any single LED segment is 25 mA. Above this temperature, the rating must be linearly derated by 0.33 mA for every 1°C increase in ambient temperature.
• Peak forward current per segment:For pulsed operation, higher currents are permissible. Under conditions of a 1/10 duty cycle and a pulse width of 0.1 ms, the peak current can reach 60 mA. This is useful in dynamic scanning schemes to achieve higher instantaneous brightness during brief on-times.
• Power dissipation per segment:The maximum power dissipated as heat for a single segment is 40 mW. This value is calculated as the forward voltage (V_F) multiplied by the forward current (I_F). Exceeding this limit risks overheating and damaging the semiconductor junction.
• Forward voltage (V_F):At a drive current of 20 mA, the typical forward voltage drop of an LED segment is 2.6V, with a minimum of 2.05V. This parameter is crucial for designing the current-limiting circuit in the driver.
• Reverse voltage per segment:The maximum reverse bias voltage that can be applied to an LED segment is 5V. Exceeding this value may cause immediate and irreversible damage to the LED due to junction breakdown.
• Reverse current per segment (I_R):Wakati voltage ya kinyume ya 5V inatumika, mkondo wa uvujaji kwa kawaida ni 100 µA au chini.

2.3 Thermal and Environmental Specifications

• Safu ya Joto ya Uendeshaji:Kifaa hiki kimepangwa kufanya kazi kwa kawaida katika anuwai ya halijoto ya mazingira ya -35°C hadi +85°C. Utendaji nje ya anuwai hii hauhakikishiwi.
• Anuwai ya halijoto ya uhifadhi:Kifaa hiki kinaweza kuhifadhiwa bila uendeshaji katika anuwai ile ile ya -35°C hadi +85°C.
• Halijoto ya kuchomelea:During the assembly process, the device can withstand a maximum soldering temperature of 260°C for a maximum duration of 3 seconds, measured at a point 1.6mm below the package mounting plane. This is crucial for wave soldering or reflow soldering processes.

3. Grading and Classification System

The datasheet clearly states that the device is "classified by luminous intensity." This implies a post-production sorting (binning) process. Although this excerpt does not provide specific binning codes, typical classification for such displays involves grouping units based on their measured luminous intensity at a standard test current. This ensures customers receive displays with a consistent minimum brightness level. For I_VThamani maalum ya chini (200 µcd) na thamani ya kawaida (650 µcd) hufafanua mipaka ya kikundi hiki. Wabunifu wanapaswa kuzingatia kuwa tofauti za mwangaza zinaweza kutokea ndani ya uwiano maalum wa 2:1 wa kufanana na kati ya viwango tofauti vya nguvu, ambazo zinaweza kuathiri usawa wa mfumo wa urekebishaji kati ya skrini nyingi.

4. Performance Curve Analysis

Mwongozo unarejelea "Mikunjo ya Kawaida ya Umeme/Optiki", ambayo ni muhimu kwa kazi za kina za ubunifu. Ingawa michoro maalum haijatolewa katika maandishi, kulingana na sifa za kawaida za LED, mikunjo hii kwa kawaida hujumuisha:

• Forward Current vs. Forward Voltage (I-V Curve):This nonlinear curve shows the relationship between the voltage applied across the LED and the resulting current. It is crucial for designing constant current drivers, as a small change in voltage can cause a large change in current (and thus brightness). The curve's knee region around the typical V_F(2.6V at 20mA) is the normal operating area.
• Luminous Intensity vs. Forward Current (I-L Curve):This graph shows how the light output increases with the driving current. It is typically linear within a certain range but saturates at very high currents due to thermal effects and efficiency droop._VThe 1mA test point for I and the 20mA point for other parameters provide two key references for this curve.
• Luminous Intensity vs. Ambient Temperature:Mwanga wa LED kawaida hupungua kadri joto la kiungo linavyoongezeka. Kwa matumizi katika anuwai pana ya halijoto, mkunjo huu ni muhimu ili kuhakikisha usomaji unaendelea hata katika halijoto za juu.
• Usambazaji wa wigo:Grafu ya nguvu ya jamaa dhidi ya urefu wa wigo, inayoonyesha kilele cha ~588 nm, na upana wa nusu kufikia 15 nm, inathibitisha utoaji wa mwanga wa manjano safi.

5. Taarifa za Mitambo na Ufungaji

5.1 Vipimo vya Kimwili na Uvumilivu

The package drawing provides critical mechanical data for PCB layout and housing design. All dimensions are in millimeters. The general tolerance for unspecified dimensions is ±0.25 mm (equivalent to ±0.01 inches). Designers must incorporate these tolerances into their mechanical designs to ensure proper assembly. The drawing will detail the overall length, width, and height of the display module, the spacing between digits, segment dimensions, and the location and diameter of mounting pins.

5.2 Pin Configuration and Connection Diagram

The pin connection table is an interface map between the internal circuit and the external world. The LTC-4724JS employs a 15-pin arrangement (several of which are marked as "No Connect" or "No Pin").

• Common Cathode:Pins 1, 5, 7, and 14 are cathode connections. Pin 1 corresponds to digit 1, pin 5 corresponds to digit 2, pin 7 corresponds to digit 3, and pin 14 is the common cathode for the left-side decimal points (L1, L2, L3). This configuration enables a dynamic scanning scheme.
• Segment Anode:The remaining pins (2, 3, 4, 6, 8, 11, 12, 15) are anodes for specific segments: A, B, C, D, E, F, G, and DP (decimal point). As shown in the internal circuit diagram, segment C and segment G are shared with the left-side decimal point L3 and the common point, respectively.

Mchoro wa ndani wa mzunguko unaonyesha wazi muundo huu wa kuchanganua kwa nguvu, unaonyesha jinsi ncha tatu za nambari na sehemu za pamoja za anode zinavounganishwa. Kuelewa mchoro huu ni muhimu kwa kuendeleza ratiba sahihi ya programu na mzunguko wa kuendesha vifaa vya elektroniki.

6. Mwongozo wa Uchomeleaji na Usanikishaji

Kikomo cha juu kabisa cha joto la kuunganisha (chini ya 1.6mm ya ndege ya kusakinisha, 260°C kwa sekunde 3) hutoa mwongozo wazi kwa mchakato wa kukusanya. Kikomo hiki kinaendana na mkunjo wa kawaida wa joto wa reflow isiyo na risasi (joto la kilele kawaida huwa karibu 245-250°C). Kwa kuunganisha kwa wimbi, wakati wa kuwasiliana na pini za kuunganisha zilizoyeyuka lazima udhibitiwe ili kukaa ndani ya kikomo hiki. Inashauriwa kufuata miongozo ya kawaida ya IPC ya kuunganisha vipengele vya mashimo. Inashauriwa kupasha joto kabla ya kuunganisha ili kupunguza mshtuko wa joto. Baada ya kuunganisha, onyesho linapaswa kupozwa polepole. Utaratibu sahihi wa usindikaji wa ESD (utokaji umeme wa tuli) unapaswa kufuatwa kila wakati wakati wa mchakato wa kukusanya ili kuzuia uharibifu wa makutano nyeti ya LED.

7. Mapendekezo ya Matumizi na Mazingatio ya Ubunifu

7.1 Mazingira ya Kawaida ya Utumizi

LTC-4724JS inafaa kabisa kwa matumizi mbalimbali yanayohitaji onyesho la nambari la kompakt, lenye mwangaza, na la kuaminika. Matumizi ya kawaida ni pamoja na:

• Vifaa vya Uchunguzi na Upimaji:Digital multimeters, frequency counters, power supplies, ambapo azimio la tarakimu 3 linatosha (mfano kuonyesha 0-999).
• Udhibiti wa Viwanda na Vyombo vya Kipimo:Paneli za kipimo zinazotumika kwa joto, shinikizo, kasi au kuhesabu.
• Bidhaa za Umma za Kielektroniki:Vifaa vya sauti (onyesho la sauti la kikuza sauti), vifaa vya jikoni (kita cha kuhesabu muda, usomaji wa joto).
• Soko la nyuma la magari:Maelezo ya udhibiti yanadai kuwa na "mtazamo mpana" na "tofauti kubwa". Paneli ya kijivu/sehemu nyeupe huimarisha tofauti. Kwa mtazamo bora zaidi, skrini inapaswa kusanikishwa kwa pembe ya kulia kwa mwelekeo mkuu wa kutazama. Chini ya hali ya mwanga wa mazingira ya juu, mwangaza wa juu (kawaida 650 µcd) ni muhimu.

7.2 Mambo Muhimu ya Kukusudiwa

• Drive Circuit:Dynamic scanning drive circuit is required. This typically involves a microcontroller or a dedicated display driver IC, which can sink current into the common cathode (usually via transistors) and source current from the segment anodes. Current-limiting resistors must be provided for each segment anode (which may be shared if constant current drivers are used) to set I_Fto a safe value, typically between 10-20 mA, to balance brightness and lifespan.
• Dynamic Scanning Frequency:The refresh rate must be high enough to avoid visible flicker, typically above 60 Hz. For three digits, each digit is illuminated for approximately 1/3 of the time per cycle. The peak current can be set higher (up to the 60mA pulse rating) to compensate for the reduced duty cycle and maintain average brightness.
• Power Supply:Mahitaji ya voltage chanya (takriban 2.6V) yamaanisha kuwa usambazaji wa umeme wa mfumo lazima utoe voltage ya juu kuliko hii, ili kuacha nafasi ya kushuka kwa voltage kwenye kipingamizi cha kudhibiti mkondo na mzunguko wa kuendesha. Usambazaji wa umeme wa kawaida wa 5V ni rahisi na unaaminika.
• Pembe ya kuona na Ulinganisho wa Mwangaza:The datasheet claims a "wide viewing angle" and "high contrast." The gray face/white segments enhance contrast. For optimal viewing, the display should be mounted perpendicular to the primary viewing direction. In high-ambient-light conditions, the high brightness (650 µcd typ.) is beneficial.
• Usimamizi wa Joto:Ingawa matumizi ya nguvu kwa kila sehemu ni ya chini, joto linalojumlishwa linalotokana na sehemu nyingi zinawaka wakati mmoja (hasa chini ya mkondo wa juu) linapaswa kuzingatiwa. Inapendekezwa kutoa uingizaji hewa wa kutosha ndani ya kifuniko, hasa wakati wa uendeshaji karibu na kikomo cha juu cha joto.

8. Ulinganishi wa Teknolojia na Tofauti

Sababu kuu ya kutofautisha kwa LTC-4724JS iko katika teknolojia ya nyenzo na ufungashaji wake. Ikilinganishwa na teknolojia za zamani kama vile LED za kawaida za GaP au GaAsP, AlInGaP hutoa ufanisi mkubwa zaidi wa mwanga, na hivyo kufikia mwangaza wa juu zaidi chini ya mkondo sawa wa kuendesha. Pia, rangi ya manjano inayotokana ni iliyojaa na safi zaidi. Ikilinganishwa na mbadala za kisasa, urefu wa herufi ya inchi 0.4 hutoa usawa maalum kati ya ukubwa na uwezo wa kusomeka. Muundo wa skeni ya msimamo wa pamoja wa cathode ni kiwango kwa alama za tarakimu nyingi, lakini mpangilio maalum wa pini na mzunguko wa ndani (pamoja na cathode ya pamoja ya nukta ya desimali ya kushoto) ni ya kipekee kwa aina hii na lazima ifanane na programu ya kuendesha. Uainishaji wa nguvu ya mwanga hutoa kiwango fulani cha udhibiti wa ubora, ambacho huenda kisipatikane kwenye maonyesho yote.

9. Maswali Yanayoulizwa Mara Kwa Mara (Kulingana na Vigezo vya Kiufundi)

• Swali: Je, naweza kuendesha kiwango hiki cha kuonyesha kwa kutumia kidhibiti-kichwa cha 3.3V?Jibu: Inawezekana, lakini inahitaji muundo wa kina. Kawaida V_Fni 2.6V. Kwa kuzingatia upungufu mdogo wa voltage kwenye transistor ya kuendesha na upinzani wa kudhibiti mkondo, akiba ya usambazaji wa umeme wa 3.3V inaweza kuwa ngumu sana au haitoshi, haswa kwa kuzingatia mabadiliko ya V_F. Usambazaji wa umeme wa 5V ni wa kuaminika zaidi. Huenda ukahitaji kibadilishaji cha kiwango cha voltage au IC ya kuendesha inayotolewa na mstari wa kujitegemea wa usambazaji wa umeme wa 5V.
• Q: Kwa nini mkondo wa kilele (60mA) ni mkubwa kuliko mkondo unaoendelea (25mA)?A: Kwa kiwango cha chini cha mzunguko, LED inaweza kukabili mkondo wa papo hapo wa juu zaidi, kwani matumizi ya wastani ya nguvu na joto la kiungo hubaki ndani ya mipaka salama. Hii inatumika katika uchanganuzi wa mienendo kufikia mwangaza unaohisiwa wa juu zaidi.
• Q: Ni nini kusudi la pini ya "Hakuna Muunganisho"?A: Kwa uwezekano mkubwa ni viboreshaji vya mitambo, ili kutoshea ukubwa wa kifurushi cha kawaida cha DIP (Dual In-line Package) chenye pini 15. Hutoa uthabiti wa kimwili wakati wa kuchomelea, lakini hazina utendaji wa umeme. Usiziunganishe kwenye mzunguko wowote.
• Q: Je, thamani ya kipingamizi cha kudhibiti mkondo inaweza kuhesabiwaje?Jibu: Tumia sheria ya Ohm: R = (V_{Chanzo cha umeme}- V_F- V_{Voltage drop across the driver}) / I_F. For a 5V power supply, V_Fis 2.6V, the driver voltage drop is 0.2V, and the expected I_FFor 15mA: R = (5 - 2.6 - 0.2) / 0.015 = 146.7 Ω. A standard 150 Ω resistor is suitable. Be sure to verify the resistor's power dissipation: P = I²* R.

10. Mifano Halisi ya Usanifu na Matumizi

Consider designing a simple 3-digit voltmeter using a microcontroller. The microcontroller's ADC reads the voltage, converts it to a number between 0 and 999, and needs to display it.

1. Kiunganishi cha vifaa (Hardware Interface):Sanidi pini tatu za I/O za microcontroller kama matokeo, ili kudhibiti transistor za NPN (au safu ya transistor) zinazomwaga mkondo kutoka kwenye pini tatu za cathode za tarakimu (1, 5, 7). Pini nyingine nane za I/O (au kishindili cha kuhama kilichotumika kuokoa pini) zinasanidiwa kama matokeo, kutoa mkondo kupitia upinzani wa kikomo wa 150Ω kwa kila mmoja hadi kwenye pini nane za anode za sehemu (A, B, C, D, E, F, G, DP).
2. Mfuatano wa programu (Software Routine):Mzunguko mkuu unatekeleza uchunguzi wa mienendo. Hufunga anodi zote za nambari. Kisha huweka muundo wa sehemu kwenye pini ya anodi kwa nambari 1 (kwa mfano kuonyesha "5"). Kisha huwezesha (kupitia transistor kutoa njia ya ardhi) anodi ya nambari 1. Kusubiri muda mfupi (kwa mfano milisekunde 2-3). Kisha huzima nambari 1, huweka muundo wa sehemu kwa nambari 2, huwezesha anodi ya nambari 2, kusubiri, na kurudia mchakato huu kwa nambari 3. Mzunguko huu unaendelea kurudiwa. Kilele cha sasa kwa kila sehemu kinaweza kuwekwa kuwa takriban 20mA. Kwa uwiano wa kazi wa 1/3, wastani wa sasa ni takriban 6.7mA, iko ndani kabisa ya viwango vya mfululizo.
3. Matokeo:Kutokana na athari ya kudumu kwa kuona, nambari zote tatu zinaonekana kuwaka wakati huo huo na kwa utulivu, zikiashiria thamani ya voltage iliyopimwa.

11. Utangulizi wa Kanuni za Kiufundi

LTC-4724JS is based on solid-state lighting technology using AlInGaP (Aluminum Indium Gallium Phosphide) semiconductors. When a forward voltage exceeding the diode's bandgap voltage is applied, electrons and holes are injected into the active region of the semiconductor structure. They recombine, releasing energy in the form of photons (light). The specific composition of the AlInGaP alloy determines the bandgap energy, which directly dictates the wavelength (color) of the emitted light—in this case, yellow (approximately 587-588 nm). The opaque GaAs substrate absorbs any backward-emitted light, improving overall efficiency by reducing internal reflections that do not contribute to effective forward light output. The seven-segment format is a standardized method for forming numeric characters by selectively illuminating seven independent bar-shaped LED segments (labeled A through G).

12. Mwelekeo na Mazingira ya Kiufundi

Ingawa aina hii mahususi inatumia teknolojia ya AlInGaP iliyothibitishwa, uwanja mpana wa maonyesho ya LED bado unaendelea kukua. Mienendo inajumuisha utumiaji wa nyenzo zenye ufanisi zaidi (kama vile InGaN kwa mwanga wa bluu/kijani/njeupe), ukuzaji wa ufungashaji wa Chip-on-Board (COB) na Surface-Mount Device (SMD) kwa msongamano mkubwa na ukubwa mdogo, na ujumuishaji wa madereva na vidhibiti moja kwa moja kwenye moduli ya maonyesho (maonyesho ya kisasa). Hata hivyo, kwa matumizi mahususi yanayohitaji mwanga wa manjano safi na wenye ufanisi katika ufungashaji wa kawaida wa kupitia-tundu, maonyesho yanayotegemea AlInGaP (kama vile LTC-4724JS) bado ni suluhisho la kuaminika na la kiuchumi. Urahisi wao, uthabiti, na urahisi wa kuunganishwa na vidhibiti vya msingi vya mikrokontrolla, huhakikisha kuwa bado wana umuhimu katika miundo mingi ya viwanda na ya watumiaji ambayo haihitaji maonyesho maalum ya michoro.