LTC-2621JD-04 LED Digital Tube Datasheet - 0.28 Inch Character Height - Super Bright Red (650nm) - 2.6V Forward Voltage - Technical Documentation

1. Product Overview

The LTC-2621JD-04 is a compact, high-performance three-digit seven-segment display module, specifically designed for applications requiring clear numeric readouts. Its primary function is to provide visual numeric output in electronic devices. The core advantage of this device lies in its use of advanced AlInGaP (Aluminum Indium Gallium Phosphide) semiconductor technology to manufacture the LED chips, which are fabricated on an opaque GaAs substrate. This combination yields the iconic "Super Bright Red" luminous characteristic. The display features a gray panel with white segment design, enhancing contrast and readability. Target markets include industrial instrumentation, consumer electronics, test and measurement equipment, and any embedded system requiring reliable, low-power numeric display.

1.1 Key Features and Advantages

• Character Height:0.28 inches (7.0 mm), achieving a good balance between size and visibility.
• Segment Design:Segments ya mfululizo na sare, huhakikisha muonekano bora na uzuri wa herufi.
• Ufanisi wa Nishati:Matumizi ya nguvu ya chini, inafaa kwa matumizi yanayotumia betri au yanayozingatia matumizi ya nishati.
• Utendaji wa Kioo:High brightness and high contrast ensure good readability under various lighting conditions.
• Viewing Angle:Wide viewing angle allows reading the display content from off-axis positions.
• Uaminifu:Uaminifu wa mfumo dhabiti, hakuna sehemu zinazosonga, na hivyo kuwa na maisha marefu ya huduma.
• Udhibiti wa Ubora:Vifaa vinatengenezwa kulingana na nguvu ya mwanga ili kuhakikisha mwangaza unaolingana kati ya vikundi tofauti vya uzalishaji.

2. Maelezo ya Vipimo vya Kiufundi

Sehemu hii inachambua kwa kina na kwa uwazi vigezo muhimu vya kiufundi vya kifaa kulingana na hati ya maelezo ya kiufundi.

2.1 Viwango vya Juu Kabisa

These ratings define the stress limits that may cause permanent damage to the device. Operation at or beyond these limits is not guaranteed.

• Maximum Power Dissipation per Segment:Maximum 70 mW. This limits the maximum continuous power that a single segment can dissipate as heat.
• Peak forward current per segment:Maximum 90 mA, but only under specific pulse conditions: 1/10 duty cycle and 0.1 ms pulse width. This rating applies to multiplexed or short-duration high-brightness pulses.
• Continuous forward current per segment:Maximum 25 mA at 25°C. This current derates linearly at 0.33 mA/°C when the ambient temperature (Ta) exceeds 25°C. For example, at 85°C, the maximum allowable continuous current is approximately: 25 mA - ((85°C - 25°C) * 0.33 mA/°C) = 5.2 mA.
• Reverse voltage per segment:Upeo wa juu ni 5 V. Kuzidi thamani hii kunaweza kusababisha kuvunjika kwa kiungo.
• Safu ya joto la uendeshaji:-35°C hadi +85°C. Kifaa kimeundwa kufanya kazi ndani ya safu hii ya joto la mazingira.
• Safu ya joto la uhifadhi:-35°C hadi +85°C.
• Joto la kulehemu:Kiwango cha juu cha 260°C, kwa muda wa sekunde 3 kwa upeo, kipimo kinachukuliwa kwenye umbali wa milimita 1.6 chini ya ndege ya usakinishaji. Hii ni muhimu kwa mchakato wa wave soldering au reflow soldering ili kuzuia uharibifu wa joto.

2.2 Electrical and Optical Characteristics (Ta=25°C)

These are typical operating parameters under specified test conditions.

• Average Luminous Intensity (I_V):Inapokua kutoka 200 μcd (kiwango cha chini) hadi 600 μcd (kiwango cha juu), na thamani ya kawaida inayoeleweka. Inapimwa wakati mkondo wa mbele (I_F) ni 1 mA. Hii ni kigezo muhimu cha kugundua mwangaza.
• Urefu wa wimbi la kilele cha utoaji (λ_p):650 nm (thamani ya kawaida). Hii ndio urefu wa wimbi ambalo utoaji wa wigo ni wenye nguvu zaidi, na inafafanua rangi ya "nyekundu yenye mwangaza mkubwa".
• Spectral line half-width (Δλ):20 nm (typical value). This indicates spectral purity; a smaller value means the light is more monochromatic. 20nm is a typical value for AlInGaP red LEDs.
• Dominant wavelength (λ_d):639 nm (typical value). This is the single wavelength that matches the LED color as perceived by the human eye, and it is usually slightly different from the peak wavelength.
• Forward voltage per segment (V_F):Ranges from 2.1 V (minimum) to 2.6 V (maximum), with a typical value of 2.6 V at I_F=20 mA. This is crucial for designing current-limiting circuits.
• Reverse current per segment (I_R):at reverse voltage (V_RWhen the voltage is 5V, the maximum current is 100 μA.
• Luminous intensity matching ratio (I_V-m):Maximum 2:1. This specifies the maximum allowable ratio between the brightest and darkest segments/bits within the device, ensuring uniformity.

Maelezo ya Kipimo:Nguvu ya mwanga hupimwa kwa kutumia sensor na vichungi vinavyokaribia mkunjo wa majibu ya kuona ya wazi ya CIE, kuhakikisha kuwa matokeo ya kipimo yanahusiana na mtazamo wa mwanadamu wa mwangaza.

3. Mfumo wa Kupanga na Kuainisha

Spec inasema wazi kuwa kifaa "kimeainishwa kulingana na nguvu ya mwanga." Hii inamaanisha kuwa kuna mchakato wa kupanga.

• Kiwango cha kiwango cha mwanga:Kwa I_VAnuwai maalum iliyobainishwa (200-600 μcd) inaonyesha vipengele vya uzalishaji vinajaribiwa na kugawanywa katika viwango tofauti vya nguvu. Wabunifu wanaweza kuchagua kiwango kwa matumizi yanayohitaji kiwango maalum cha mwangaza au usawa mkali kati ya vielelezo vingi.
• Forward voltage:The specified range (2.1-2.6V) may also lead to voltage grading, which could be important for power supply design in large arrays.
• Wavelength:Although typical values for λ_pand λ_dare given, tight tolerance grades for specific chromaticity coordinates may be available, though not detailed in this summary datasheet.

4. Performance Curve Analysis

The datasheet references "Typical Electrical/Optical Characteristic Curves." While specific graphs are not provided in the text, we can infer their standard content and importance.

• Uzito wa Mwanga wa Jamaa dhidi ya Mkondo wa Mbele (Mkondo wa I-V):Chati hii itaonyesha jinsi pato la mwanga linavyobadilika na ongezeko la mkondo, kwa kawaida kwa uhusiano wa chini ya mstari, ikasisitiza kupungua kwa ufanisi kwenye mikondo ya juu.
• Voltage ya Mbele dhidi ya Mkondo wa Mbele:Displays the I-V characteristics of a diode, which is crucial for calculating series resistance values or designing constant current drivers.
• Relative Luminous Intensity vs. Ambient Temperature:Shows how light output decreases with increasing temperature, a key factor in thermal management.
• Spectral Distribution:A plot of relative intensity vs. wavelength, showing a peak at approximately 650nm and a full width at half maximum of 20nm.

5. Mechanical and Packaging Information

5.1 Package Dimensions

This device is packaged in a standard LED display package. All dimensions are in millimeters (mm). Unless otherwise specified for particular features, the general tolerance is ±0.25 mm (≈±0.01 inch). The exact dimensional drawing is referenced in the datasheet but is not detailed here. Key aspects include overall length, width, height, digit spacing, pin pitch, and pin dimensions.

5.2 Pin Connections and Internal Circuitry

LTC-2621JD-04 ni aina yaMultiplexed common anodeKifaa. Hii inamaanisha kuwa anode ya kila tarakimu imeunganishwa ndani kwa tarakimu, wakati cathode ya kila aina ya sehemu (A-G, DP) inatumika kwa pamoja kati ya tarakimu mbalimbali.

Ufafanuzi wa pini (mfuko wa pini 16):

• Pin 1: Cathode D
• Pin 2: Common Anode (Digit 1)
• Pin 3: Cathode D.P. (Decimal Point)
• Pin 4: Cathode E
• Pin 5: Common Anode (Digit 2)
• Pin 6: Cathode C
• Pin 7: Cathode G
• Pin 8: Common Anode (Digit 3)
• Pin 9: No Connection
• Pin 10: No pin
• Pin 11: No pin
• Pin 12: Cathode B
• Pin 13: Common anode for L1, L2, L3 (possibly a colon or other marker)
• Pin 14: No pin
• Pin 15: Cathode A
• Pin 16: Cathode F

Internal circuit diagram:Mchoro wa kanuni unaonyesha nodi tatu za anodi za kawaida (moja kwa kila tarakimu) zikiunganishwa kwa pini 2, 5 na 8. Kathodi ya kila sehemu (A-G, DP) ni nodi moja inayounganishwa kwa pini yake husika, na LED ya sehemu hiyo katika kila tarakimu imeunganishwa kati ya anodi ya kawaida ya tarakimu hiyo na kathodi ya sehemu inayoshirikiwa. Muundo huu unafaa kabisa kwa uendeshaji wa multiplexing.

6. Soldering and Assembly Guide

Mwongozo muhimu unaotolewa ni viwango vya juu kabisa vya uchomaji:Kiwango cha juu cha 260°C, kwa muda usiozidi sekunde 3, kipimo kinachukuliwa kwenye hatua 1.6 mm chini ya ndege ya usakinishaji.

• Uwekaji wa mshono wa reflow.Mkunjo wa kawaida wa uwekaji mshono wa reflow bila risasi, halijoto ya kilele isizidi 260°C, na muda wa kuwa juu ya 240°C ni mfupi sana, inapaswa kuwa ya kufanana. Sehemu ya kipimo ya milimita 1.6 ni muhimu sana kwa uthibitishaji wa mkunjo.
• Uwekaji wa mshono wa wimbi.Feasible, but contact time and temperature must be carefully controlled to meet the 260°C/3 seconds limit.
• Hand soldering:Use a temperature-controlled soldering iron. Apply heat to the PCB pad, not directly to the LED leads, and complete the soldering quickly.
• Hali ya kuhifadhi:Hifadhi katika mazingira yaliyokauka na yanayozuia umeme ndani ya anuwai maalum ya joto la kuhifadhi (-35°C hadi +85°C). Ikiwa imefichuliwa kwenye unyevunyevu, vifaa vinavyohisi unyevu vinaweza kuhitaji kukaushwa kabla ya matumizi.

7. Mapendekezo ya Utumizi

7.1 Saketi ya Kawaida ya Utumizi

A multiplexed common-anode configuration requires a driving circuit. A typical design employs:

• Microcontroller or driver IC:Inatumika kudhibiti mfuatano na data.
• Kichocheo cha biti:Transista ya PNP au swichi maalum ya upande wa juu, inayotumika kumwagia mkondo kwenye pini ya anodi ya kawaida (2, 5, 8, 13).
• Kichocheo cha sehemu:Microcontroller port or low-side driver IC (such as a 74HC595 shift register with open-drain output or a dedicated LED driver), used to sink current from the segment cathode pins (1, 3, 4, 6, 7, 12, 15, 16).
• Current Limiting Resistor:When using constant voltage drive, one resistor is needed for each segment cathode line (not for each segment LED). The resistor value is calculated using R = (V_{Power supply}- V_F) / I_FCalculation. For a 5V power supply, I_F=10 mA, V_F=2.6V, R = (5 - 2.6) / 0.01 = 240 Ω. For better uniformity, a constant current driver is preferred.

7.2 Design Considerations

• Multiplexing Frequency:使用足够高的刷新率以避免可见闪烁（通常每位>60 Hz，因此3位扫描速率>180 Hz）。
• Peak Current vs. Brightness:To achieve high average brightness while maintaining the continuous current rating, multiplexing with a higher peak current (up to 90mA pulse rating) is used. For example, driving at a 1/3 duty cycle (3 digits) with a 30mA peak current results in an average current of 10mA per segment.
• Usimamizi wa joto:Hakikisha mpangilio wa PCB unaruhusu upotezaji wa joto, hasa unapokaribia kuendesha kwa viwango vya juu vilivyopangwa. Joto la juu la mazingira litahitaji kupunguzwa kwa sasa.
• Ulinzi wa ESD:LED zinaathiriwa na umeme wa tuli. Chukua tahadhari zinazofaa za ESD wakati wa usanikishaji.

8. Technical Comparison and Differentiation

Ikilinganishwa na teknolojia za zamani kama vile LED nyekundu ya kawaida ya GaP au vionyeshi vya nambari vikubwa zaidi, LTC-2621JD-04 inatoa faida maalum:

• AlInGaP vs. GaAsP/GaP:AlInGaP technology offers significantly higher luminous efficiency, resulting in higher brightness and better visibility under ambient light. The "Super Bright Red" color is also more vivid.
• Small Character Height (0.28 inches):Gray Panel / White Segments:
• Wakati sehemu za maonyesho haziko wazi, usindikaji huu wa uso hutoa tofauti kubwa ya rangi, ikiboresha uzuri na uwezo wa kusomeka kwa maonyesho yote ikilinganishwa na paneli nyeusi kabisa au kijivu kabisa.Ngazi za nguvu:
• Uainishaji huu hutoa kiwango fulani cha udhibiti wa ubora na utabiri, ambao haupo kila wakati katika vionyeshi vya bei nafuu.9. Maswali Yanayoulizwa Mara kwa Mara (Kulingana na Vigezo vya Kiufundi)

Q1: Lengo la usanidi wa "common anode" ni nini?

A1: Anode ya Pamoja hurahisisha uunganishaji mwingi. Unawasha tarakimu moja kwa wakati mmoja kwa kutumia voltage chanya kwa pini ya anode yake, wakati huo huo ukigundua cathode ya sehemu unayotaka kuwasha. Hii inapunguza idadi ya pini zinazohitajika za kuendesha kutoka (sehemu 7 + 1 DP) * tarakimu 3 = 24 hadi anode 3 + cathode 8 = 11.
Q2: Je, thamani ya upinzani ya kuendesha kionyeshi hiki inahesabiwaje?

A2: Tumia sheria ya Ohm: R = (V
Power supply_{- V}) / I_F. Tumia V ya juu kwenye spec sheet_F(2.6V), ili kuhakikisha kuwa hata kwa sehemu zenye V ya juu_F, kuna kushuka kwa kutosha kwa voltage kwenye resistor. Chagua I kulingana na mwangaza unaohitajika_F, ukidumisha ndani ya viwango vya kuendelea (25mA kwenye 25°C) au visivyo vya mfululizo._FQ3: Naweza kutumia microcontroller ya 3.3V kuendesha kionyeshi hiki?

A3: Inawezekana, lakini kuna mipaka. Ikiwa V
ni 2.6V, basi kwenye 3.3V, kuna tofauti ya voltage ya 0.7V tu kwenye kipingamizi cha kudhibiti mkondo. Kwa mkondo wa 10mA, R=70Ω. Thamani hii ya chini ya upinzani inawezekana, lakini mabadiliko ya V_Fyatasababisha mabadiliko makubwa ya mwangaza. Ili kufikia utendakazi thabiti, inashauriwa kutumia kiendeshi cha mkondo wa kudumu au kibadilishaji cha kuongeza voltage ili kutoa voltage ya juu ya usambazaji (kama 5V)._FQ4: Inamaanisha nini "uwiano wa kufanana wa nguvu ya mwanga 2:1"?

A4: Hii inamaanisha kuwa ndani ya kitengo kimoja cha LTC-2621JD-04, chini ya hali sawa (I
=1mA) wakati wa kupima, mwangaza wa sehemu au tarakimu angavu zaidi hautazidi mara mbili ya mwangaza wa sehemu au tarakimu giza zaidi. Hii inahakikisha usawa wa kuona._F10. Design and Use Case Studies

Scenario: Designing a Portable Digital Multimeter Display

LTC-2621JD-04 is an excellent choice. Its 0.28-inch digit height is highly legible. The low power requirement is crucial for battery life. The multiplexed design minimizes the number of microcontroller pins. The design will use the microcontroller's timer to cycle through digits 1, 2, and 3 at approximately 200 Hz. Segment data will be fetched from a look-up table. To save power, the display brightness (I
) can be dynamically adjusted based on ambient light sensed by a phototransistor. The high-contrast gray/white panel ensures readability in both dark and bright workshop environments. The AlInGaP ultra-bright red LED provides a clear, compelling readout._F11. Introduction to Technical Principles

LTC-2621JD-04 is based on

AlInGaP (aluminum indium gallium phosphide)semiconductor material, which is epitaxially grown onGaAs (gallium arsenide)On the substrate. The "opaque" GaAs substrate is used because it absorbs the emitted light, but the AlInGaP active layer has a sufficiently high internal efficiency, allowing enough light to escape from the top of the chip. When a forward voltage is applied across the p-n junction, electrons and holes are injected into the active region. Their recombination releases energy in the form of photons. The specific composition of the AlInGaP alloy determines the bandgap energy, which directly defines the wavelength (color) of the emitted light—in this case, approximately 650 nm (red). The seven-segment format is formed by placing multiple miniature LED chips (or a single chip with multiple isolated junctions) under a patterned optical lens/diffuser to create recognizable digit segments.12. Technology Trends and Background

Ingawa kifaa hiki maalum kinatumia teknolojia ya mashimo ya kupenyeza, mfumo wa nyenzo za msingi wa AlInGaP bado una uhusiano mkubwa. Mwelekeo wa teknolojia za kuonyesha ni pamoja na:

Miniaturization:

• Transitioning to Surface-Mount Device (SMD) packaging to enable automated assembly, even for multi-digit displays.Integration:
• Combining LED arrays with driver ICs in a single package or module to simplify design.Nyenzo za hali ya juu:
• Utafiti unaoendelea kwa nyenzo kama vile GaN (kwa rangi ya bluu/kijani/njeupe) na AlInGaP ili kuboresha ufanisi na kukuza rangi mpya. Kwa mwanga mwekundu/wa machungwa/wa manjano, AlInGaP ndio teknolojia ya hali ya juu inayoongoza.Mabadiliko ya matumizi:
• Ingawa maonyesho ya sehemu saba tofauti yamekomaa, bado ni muhimu katika matumizi ambayo unyenyekevu, gharama, uaminifu, na kuonekana kwa juu ni muhimu (udhibiti wa viwanda, vifaa vya nyumbani, vyombo vya kupimia). Yanakaa pamoja na teknolojia mpya kama OLED na LCD, kila moja ikihudumia sehemu tofauti za soko kulingana na mambo kama vile pembe ya kuona, uwezo wa kusomeka kwenye jua, matumizi ya nguvu, na gharama.LTC-2621JD-04 inawakilisha suluhisho thabiti, lililokomaa ndani ya mazingira haya yanayobadilika, ikitoa usawa uliothibitishwa wa utendaji, uaminifu, na gharama kwa matumizi yake yaliyokusudiwa.

The LTC-2621JD-04 represents a robust, well-established solution within this evolving landscape, offering a proven balance of performance, reliability, and cost for its intended applications.