LTS-2806SKG-P LED Display Datasheet - 0.28 Inch Digit Height - AlInGaP Green - 2.6V Forward Voltage - English Technical Document

1. Product Overview

LTS-2806SKG-P shine ne wani na'ura mai nuni ta LED mai haɗa kai ta sama (SMD) wacce aka tsara don aikace-aikacen da ke buƙatar nuna lambobi a sarari a cikin ƙaramin siffa. Tana da tsayin lambobi na inci 0.28 (mm 7.0), wanda ya sa ta dace da haɗawa cikin na'urorin lantarki daban-daban inda sarari ya yi ƙarami. Na'urar nuni tana amfani da fasahar semiconductor ta AlInGaP (Aluminum Indium Gallium Phosphide) don sassanta masu haskakawa, wanda ke samar da fitar da launin kore na musamman. Kunshin yana da fuskar launin toka da sassa farare, yana haɓaka bambanci da karantawa. An rarraba wannan na'urar don ƙarfin haske kuma tana bin umarnin maras gubar da RoHS (Ƙuntata Abubuwa Masu Haɗari), wanda ya sa ta dace da masana'antar lantarki na zamani.

1.1 Siffofi Masu Muhimmanci

• Girman Lamba: 0.28 inch (7.0 mm) character height.
• Technology: Utilizes AlInGaP LED chips on a non-transparent GaAs substrate for green emission.
• Uniformity: Continuous and uniform segment illumination.
• Power Efficiency: Low power requirement for energy-sensitive applications.
• Optical Performance: Excellent character appearance, high brightness, and high contrast ratio.
• Viewing Angle: Wide viewing angle for visibility from various positions.
• Reliability: Solid-state construction ensures long operational life.
• Quality Control: Devices are categorized (binned) based on luminous intensity.
• Environmental Compliance: Lead-free package compliant with RoHS standards.

1.2 Device Identification

The part number LTS-2806SKG-P Identifies this specific model. It is a common anode configuration AlInGaP green LED display.

2. Technical Parameters: In-Depth Objective Interpretation

This section provides a detailed analysis of the electrical and optical specifications that define the performance boundaries and operating conditions of the LTS-2806SKG-P display.

2.1 Absolute Maximum Ratings

These ratings define the stress limits beyond which permanent damage to the device may occur. Operation under or at these limits is not guaranteed and should be avoided in reliable design.

• Power Dissipation per Segment: 70 mW. This is the maximum power that can be safely dissipated by a single LED segment without causing thermal damage.
• Peak Forward Current per Segment: 60 mA. This current is permissible only under pulsed conditions (1/10 duty cycle, 0.1 ms pulse width) to prevent overheating.
• Continuous Forward Current per Segment: 25 mA at 25°C. This rating decreases linearly above 25°C at a derating factor of 0.28 mA/°C. For example, at 85°C, the maximum continuous current would be approximately: 25 mA - (0.28 mA/°C * (85°C - 25°C)) = 25 mA - 16.8 mA = 8.2 mA.
• Operating & Storage Temperature Range: -35°C to +105°C. The device can be stored and operated within this full range.
• Soldering Temperature: The package can withstand iron soldering at 260°C for 3 seconds, measured 1/16 inch (≈1.6 mm) below the seating plane.

2.2 Electrical & Optical Characteristics

These are the typical performance parameters measured under specified test conditions (Ta=25°C). They are used for circuit design and performance expectation.

• Average Luminous Intensity (I_V): This is the primary measure of brightness.
  • Minimum: 201 µcd, Typical: 501 µcd at I_F = 2 mA.
  • Typical: 5210 µcd at I_F = 20 mA. Hii inaonyesha uhusiano usio wa mstari kati ya mkondo na utoaji wa mwanga; ongezeko la mara 10 la mkondo hutoa takriban ongezeko la mara 10 la ukali katika safu hii.
  • Upimaji hufuata mkunjo wa jibu la jicho la CIE kwa usahihi.
• Sifa za Wavelength:
  • Peak Emission Wavelength (λ_p): 574 nm (typical). This is the wavelength at which the emitted optical power is greatest.
  • Dominant Wavelength (λ_d): 571 nm (typical). This is the single wavelength perceived by the human eye, defining the color (green).
  • Spectral Line Half-Width (Δλ): 15 nm (typical). This indicates the spectral purity; a smaller value means a more monochromatic color.
• Forward Voltage per Chip (V_F): 2.6 V (typical), with a maximum of 2.6 V at I_F = 20 mA. Designers must ensure the driving circuit can provide this voltage.
• Reverse Current (I_R): 100 µA (maximum) at V_R = 5V. This parameter is for test purposes only; applying continuous reverse voltage is not recommended.
• Luminous Intensity Matching Ratio: 2:1 (maximum). This specifies the maximum allowable brightness variation between segments within a single device, ensuring visual uniformity.
• Cross Talk: ≤ 2.5%. This defines the maximum amount of unintended light emission from a non-activated segment when an adjacent segment is lit.

2.3 Binning System Explanation

The datasheet states the device is "categorized for luminous intensity." This implies a binning process where manufactured units are sorted (binned) based on measured light output at a standard test current (likely 2 mA or 20 mA). Designers can select bins to ensure consistent brightness across multiple displays in a product. The specific bin codes or intensity ranges are not detailed in this document but would typically be available from the manufacturer for procurement.

3. Performance Curve Analysis

While specific graphical curves are referenced in the datasheet, their typical implications are analyzed here based on standard LED behavior and the provided parameters.

3.1 Forward Current vs. Forward Voltage (I-V Curve)

The typical V_F 2.05V zuwa 2.6V a 20mA yana nuna halayyar kunna diode. Lankwasa zai nuna haɓakar haɓakar yanzu bayan ƙarfin kunna (~1.8-2.0V don AlInGaP), ya zama mafi layi a manyan yanayin yanzu. Ana ba da shawarar direban yanzu akai-akai fiye da direban ƙarfin lantarki akai-akai don tabbatar da ingantaccen fitowar haske da hana guduwar zafi.

3.2 Ƙarfin Haskakawa da Gaban Yanzu (Lankwasa I-L)

The data points (2mA -> 501 µcd, 20mA -> 5210 µcd) suggest a largely linear relationship between current and light output in this operating range. However, efficiency (light output per unit of electrical power) typically decreases at very high currents due to increased heat. The derating of continuous current with temperature directly relates to preserving this efficiency and device lifetime.

3.3 Spectral Distribution

With a dominant wavelength of 571 nm and a half-width of 15 nm, the emitted light is a relatively pure green. The peak at 574 nm is slightly higher, which is common. This spectral information is crucial for applications where color consistency or specific wavelength interaction is important.

4. Mechanical & Package Information

4.1 Package Dimensions

The device conforms to a standard SMD footprint. Key dimensional notes include:

• All dimensions are in millimeters with a general tolerance of ±0.25 mm unless specified otherwise.
• Specific quality controls are defined for the display face: foreign material on segments ≤ 10 mils, ink contamination ≤ 20 mils, bubbles in segments ≤ 10 mils, and bending of the reflector ≤ 1% of its length.
• The plastic pin's burr must not exceed 0.1 mm.

A detailed dimensioned drawing is provided in the original datasheet for PCB land pattern design.

4.2 Internal Circuit Diagram & Pin Connection

The display has a common anode configuration. This means the anodes (positive terminals) of all LED segments are connected internally to common pins (Pin 4 and Pin 9). Each segment cathode (negative terminal) has its own dedicated pin. To illuminate a segment, its corresponding cathode pin must be driven low (connected to ground or a current sink) while the common anode is held high (connected to the positive supply via a current-limiting resistor).

Pinout Definition:
1: No Connection (N/C)
2: Cathode D
3: Cathode E
4: Common Anode
5: Cathode C
6: Cathode DP (Decimal Point)
7: Cathode B
8: Cathode A
9: Common Anode
10: Cathode F
11: No Connection (N/C)
12: Cathode G

The dual common anode pins (4 & 9) are likely connected internally and provide flexibility in PCB routing and potentially better current distribution.

5. Soldering & Assembly Guidelines

5.1 SMT Soldering Instructions

The device is intended for reflow soldering processes. Critical instructions include:

• Maximum Reflow Cycles: The device can withstand a maximum of two reflow soldering processes. A complete cooling down to ambient temperature is required between the first and second cycle.
• Recommended Reflow Profile:
  • Pre-heat: 120–150°C.
  • Pre-heat time: Maximum 120 seconds.
  • Peak temperature: Maximum 260°C.
  • Time above liquidus: Maximum 5 seconds.
• Hand Soldering (Iron): If necessary, iron temperature should not exceed 300°C, and contact time should not exceed 3 seconds.

Adhering to these profiles prevents thermal damage to the LED chips, plastic housing, and internal wire bonds.

5.2 Recommended Soldering Pattern

A land pattern (footprint) recommendation is provided to ensure reliable solder joint formation and mechanical stability. This pattern considers the pad size, shape, and spacing relative to the device's terminals to achieve proper solder fillets and avoid bridging.

5.3 Moisture Sensitivity & Storage

SMD displays are shipped in moisture-proof packaging (likely with a desiccant and humidity indicator card).

• Storage Conditions: Unopened bags should be stored at ≤ 30°C and ≤ 60% Relative Humidity (RH).
• Exposure: Once the sealed bag is opened, the devices begin to absorb moisture from the environment.
• Baking Requirement: If exposed to ambient conditions beyond the specified floor life (not stated, but typically 168 hours for a Level 3 device), the parts MUST be baked before reflow to drive out absorbed moisture. Failure to do so can cause "popcorning" or internal delamination during the high-temperature reflow process.
• Baking Parameters (only once):
  • For parts in reel: 60°C for ≥ 48 hours.
  • For parts in bulk: 100°C for ≥ 4 hours or 125°C for ≥ 2 hours.

6. Packaging & Ordering Information

6.1 Packing Specifications

The devices are supplied on tape-and-reel for automated pick-and-place assembly.

• Reel Type: Standard 13-inch (330 mm) diameter reel.
• Quantity per Reel: 1000 pieces.
• Packing Length: 38.5 meters of carrier tape per 22-inch reel (this seems to reference the tape length, possibly for a larger master reel).
• Minimum Order Quantity (MOQ): For remainder quantities, the minimum pack is 250 pieces.
• Carrier Tape: Yana da baƙar polystyrene gami mai ɗaukar wuta. Girman ya yi daidai da ƙa'idodin EIA-481. Teburin yana da iyakar lanƙwasa na 1 mm akan 250 mm kuma kauri na 0.40 ± 0.05 mm.
• Leader & Trailer: Teburin ya haɗa da jagora (≥ 400 mm) da trailer (≥ 40 mm) don ciyarwar na'ura, tare da mafi ƙarancin tazarar 40 mm tsakanin ƙarshen abubuwan da farkon trailer.

7. Application Suggestions & Design Considerations

7.1 Typical Application Scenarios

• Consumer Electronics: Digital readouts on appliances, audio equipment, power strips, or chargers.
• Instrumentation: Panel meters, test equipment displays, or control system interfaces.
• Industrial Controls: Status indicators, counter displays, or parameter readouts on machinery.
• Automotive Aftermarket: Displays for auxiliary gauges or custom electronic modules (consider extended temperature requirements).

7.2 Design Considerations

• Current Limiting: Always use a series current-limiting resistor for each common anode connection. The resistor value is calculated as R = (V_supply - V_F) / I_FFor a 5V supply and a target I_F of 10 mA with V_F ~2.4V: R = (5 - 2.4) / 0.01 = 260 Ω. Use the next standard value (270 Ω).
• Multiplexing: For multi-digit displays, a multiplexing scheme can be used where common anodes of different digits are driven sequentially at a high frequency, while the cathodes (segments) are driven with the pattern for the active digit. This significantly reduces the number of required I/O pins.
• Heat Management: Observe the current derating curve for elevated ambient temperatures. Ensure adequate PCB copper or ventilation if operating near the maximum temperature or current limits.
• ESD Protection: While not explicitly stated, standard ESD (Electrostatic Discharge) handling precautions should be observed during assembly.

8. Technical Comparison & Differentiation

Compared to other single-digit SMD displays, the LTS-2806SKG-P's key differentiators are:

• Teknolojia ya Nyenzo: Matumizi ya AlInGaP chips yanatoa ufanisi wa juu zaidi na uwezekano wa utulivu bora wa joto kwa mionzi ya kijani ikilinganishwa na teknolojia za zamani kama GaP.
• Mwangaza: A typical intensity of over 5000 µcd at 20 mA is quite bright for a 0.28-inch display, suitable for well-lit environments.
• Contrast: The gray face/white segment design is optimized for high contrast, improving readability.
• Package: The lead-free, RoHS-compliant SMD package aligns with modern environmental regulations and automated assembly lines.

9. Frequently Asked Questions (Based on Technical Parameters)

9.1 What is the difference between peak wavelength and dominant wavelength?

Peak wavelength (λ_p=574 nm) is the physical peak of the light spectrum emitted. Dominant wavelength (λ_d=571 nm) is the single wavelength that would be perceived by the human eye as having the same color. They often differ slightly. Designers concerned with color matching should reference the dominant wavelength.

9.2 Can I drive this display with a 3.3V microcontroller pin directly?

A'a. Ƙarfin gaba (V_F) yawanci shine 2.05-2.6V. Duk da cewa 3.3V ya fi wannan, dole ne ka haɗa da resistor mai iyakancewar halin yanzu. Bugu da ƙari, fil ɗin GPIO na microcontroller yawanci ba zai iya samar da ko ɗaukar isasshen halin yanzu (25 mA ci gaba da matsakaici kowane sashi) don tuƙi kai tsaye ba. Yi amfani da transistor ko ƙayyadadden IC direban LED.

9.3 Me yasa akwai fil ɗin anode gama gari guda biyu?

Having two pins (4 and 9) internally connected to the common anode allows for more flexible PCB layout, can help distribute current more evenly across the display, and provides redundancy in case one solder joint is faulty.

9.4 Yaya zan fassara ma'anar "2:1" na daidaitawar haske?

Wannan yana nufin cewa a cikin na'ura guda ɗaya, mafi haske sashi ba zai fi haske sau biyu fiye da mafi duhu sashi ba lokacin da aka sarrafa shi a ƙarƙashin yanayi iri ɗaya (I_F=2mA). This ensures visual uniformity of the displayed number.

10. Practical Design & Usage Case Study

Scenario: Designing a simple digital temperature readout for a prototype device. The microcontroller has limited I/O pins.
Implementation: Use a 3-digit version of a similar display (or three LTS-2806SKG-P units). Connect all corresponding segment cathodes (A, B, C, D, E, F, G, DP) together across the three digits, using 8 microcontroller pins. Connect each digit's common anode to a separate microcontroller pin via a small NPN transistor (e.g., 2N3904) to handle the higher cumulative segment current. The microcontroller firmware rapidly cycles (multiplexes) through enabling each digit's anode transistor one at a time while outputting the segment pattern for that digit. A refresh rate of 100 Hz or higher prevents visible flicker. Current-limiting resistors are placed on the common anode lines (before the transistors). This approach controls 3 digits with only 8+3=11 I/O pins, instead of 8*3=24 pins for direct drive.

11. Principle Introduction

The LTS-2806SKG-P operates on the principle of electroluminescence in a semiconductor p-n junction. When a forward voltage exceeding the diode's turn-on voltage is applied, electrons from the n-type AlInGaP layer recombine with holes from the p-type layer. This recombination event releases 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, green (~571 nm). The non-transparent GaAs substrate helps reflect light outward, improving efficiency. Each segment of the digit is formed by one or more of these tiny LED chips wired in parallel or series within the package.

12. Development Trends

The evolution of SMD LED displays like the LTS-2806SKG-P follows broader trends in optoelectronics:

• Increased Efficiency: Ongoing material science research aims to improve lumens per watt (efficacy), reducing power consumption for the same brightness.
• Miniaturization: Yayinda 0.28-inch shine standard, amma a cikin na'urori masu matuƙar ƙanƙanta akwai buƙatar ƙananan tsayin lambobi, wanda ke tura iyakokin fasahar marufi da guntu.
• Enhanced Color Gamut & Options: Ci gaba a cikin phosphor da kayan semiconductor kai tsaye (kamar InGaN don shuɗi/kore) na iya ba da launuka masu haske da cikakkiyar jikewa ko sabbin zaɓuɓɓukan launi a cikin irin wannan siffofi.
• Integration: Future devices may integrate the LED driver IC or logic (e.g., a BCD-to-7-segment decoder) directly into the display package, simplifying system design.
• Improved Thermal Performance: New package materials and designs to better dissipate heat, allowing for higher drive currents and brightness or improved longevity at high ambient temperatures.

These trends focus on providing higher performance, greater design flexibility, and increased reliability in increasingly demanding applications.