LTS-2807CKD-P LED Digital Tube Datasheet - 0.2 Inch Character Height - Super Red - 2.6V Forward Voltage - 70mW Power Consumption - Simplified Chinese Technical Document

1. Product Overview

LTS-2807CKD-P na'urar haɗawa ta saman (SMD) ce, an ƙera ta azaman bututun nuni na lamba ɗaya. Babban aikinta shine samar da nuni na lamba mai haske kuma abin dogaro a cikin ƙulli mai ƙarami da na zamani, wanda ya dace da tsarin haɗawa ta atomatik. Na'urar tana amfani da ƙirar AlInGaP (aluminum indium gallium phosphide) mai ci gaba da girma akan tushen GaAs don samar da fitowar haske mai ja mai ƙarfi. An zaɓi wannan fasahar kayan saboda ingantacciyar inganci da kwanciyar hankali wajen samar da haske mai ja mai ƙarfi. Ƙirar gani tana amfani da allon launin toka tare da alamomin sassa masu launin fari, wannan haɗin yana nufin haɓaka bambanci da iya karantawa a ƙarƙashin yanayin haske daban-daban, yana mai da shi dace sosai don kayan amfani na masu amfani, allunan kayan aiki, da mu'amalar sarrafa masana'antu inda sarari ya yi ƙunci kuma iya karantawa yana da mahimmanci.

1.1 Key Features and Advantages

This product is defined by several key performance and reliability characteristics that set it apart in the small-size display market.

• Compact Form Factor:The 0.2-inch (5.08 mm) character height allows it to be integrated into high-density PCBs without sacrificing the digit size.
• Optical Performance:Thanks to the AlInGaP chip and gray background with white characters design, this display offers high brightness and excellent contrast. The wide viewing angle ensures clear visibility from different positions.
• Segment Uniformity:Segment design is used to achieve continuous and uniform illumination, preventing the appearance of bright spots or dark areas that could impair the appearance of characters.
• Energy Efficiency:Low power consumption requirements help reduce overall system power usage.
• Quality and Reliability:This device features solid-state reliability and is classified according to luminous intensity, meaning products are binned to ensure brightness uniformity. Meanwhile, it adopts a lead-free package structure compliant with the RoHS environmental directive.

2. Detailed Technical Specifications

This section provides a detailed and objective analysis of the operational limits and performance characteristics of the device under defined conditions.

2.1 Absolute Maximum Ratings

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

• Power dissipation per segment:Maximum 70 mW. Exceeding this value may lead to overheating and catastrophic failure.
• Peak forward current per segment:60 mA, but only under pulse conditions (1/10 duty cycle, 0.1ms pulse width). This is suitable for brief, high-intensity flashes.
• Continuous forward current per segment:25 mA at 25°C. This rating is linearly derated as the ambient temperature (Ta) rises above 25°C, with a derating factor of 0.28 mA/°C. For example, at 85°C, the maximum continuous current is approximately 25 mA - (0.28 mA/°C * 60°C) = 8.2 mA.
• Temperature Range:Operating and storage temperature range is -35°C to +105°C.
• Solderability:The device can withstand soldering with an iron at 260°C for 3 seconds, with the iron tip positioned at least 1/16 inch below the mounting plane.

2.2 Electrical and Optical Characteristics

These are typical performance parameters measured at Ta=25°C, representing expected behavior under normal operating conditions.

• Luminous Intensity (Iv):Light output is current dependent. At a forward current (I_F) of 1 mA, the intensity ranges from 201 to 650 µcd (microcandelas). At 10 mA, the typical value rises to 8250 µcd. These measurements have a tolerance of ±15%.
• Wavelength Characteristics:This device emits an ultra-red spectrum. The peak emission wavelength (λ_p) is 650 nm. The dominant wavelength (λ_d) is 639 nm, with a tolerance of ±1 nm. The spectral line half-width (Δλ) is 20 nm, indicating the distribution range of the emitted light wavelengths.
• Forward Voltage (V_F):In I_F=20 mA, the typical value is 2.6V, with a tolerance of ±0.1V. The specified minimum value is 2.05V.
• Reverse current (I_R):At reverse voltage (V_RWhen the reverse voltage is 5V, the maximum current is 100 µA. This parameter is for test purposes only; the device is not designed for continuous reverse bias operation.
• Luminous intensity matching ratio:In I_FAt =1 mA, the maximum ratio between segment codes within a similar luminous area is 2:1. This specifies the maximum allowable brightness difference between segment codes.
• Crosstalk:Specified as ≤ 2.5%, referring to the unwanted illumination of non-selected segments when driving adjacent segments.

3. Grading and Classification System

The datasheet indicates that the product is "classified according to luminous intensity," which implies a binning process exists.

• Luminous Intensity Binning:Devices are tested based on their measured light output at a standard test current (e.g., 1 mA or 10 mA) and sorted into different bins. This ensures designers receive LEDs with consistent brightness levels for a uniform display appearance.
• Wavelength Binning:Although binning is not explicitly stated, the strict tolerance of ±1 nm for the dominant wavelength indicates tight process control, ensuring all devices have highly consistent color output.
• Forward Voltage Screening:Specified V_FTolerance ya ±0.1V inaonyesha kifaa kimeweza kuchaguliwa kukidhi kigezo hiki cha umeme, na hivyo kusaidia uthabiti wa tabia ya mzunguko wa kuendesha.

4. Performance Curve Analysis

Ingawa dondoo la PDF lililotolewa linataja mikunjo ya kawaida lakini haionyeshi, uchambuzi wa kawaida wa vifaa kama hivi unapaswa kujumuisha:

• I-V (Current-Voltage) curve:It will show an exponential relationship between forward voltage and current, with the knee voltage of AlInGaP red LED being approximately 2.0-2.2V.
• Luminous intensity vs. forward current (I_v-I_F):Anadago a cikin ƙananan wutar lantarki kusa da layi, a cikin manyan wutar lantarki yana iya nuna tasirin jikewa saboda tasirin zafi da raguwar inganci.
• Ƙarfin haske vs. Yanayin yanayi:Zai nuna raguwar fitar da haske yayin da zafin jiki ya tashi, wannan shine mahimmin abu na ƙira mai dogaro.
• Rarraba bakan:The graph showing the relationship between intensity and wavelength, centered at 650 nm (peak) with a half-width of 20 nm, confirms the ultra-red chromaticity point.

5. Mechanical and Packaging Information

5.1 Package Dimensions

The device has a defined SMD pad layout. Key dimensional notes include: all dimensions are in millimeters with a general tolerance of ±0.25 mm unless otherwise specified. Specific quality control requirements are noted, such as restrictions on foreign material, ink contamination, bubbles within the segment area, and plastic pin burrs. Due to the small package size, the part marking is abbreviated as "2807CKD-P" (omitting the "LTS" prefix).

5.2 Internal Circuit and Pin Arrangement

The device employs acommon anodeconfiguration. The internal circuit diagram shows ten pins, corresponding to the following connections: two pins are dedicated to the common anode (pins 3 and 8). The remaining pins are the individual cathodes for segments A, B, C, D, E, F, G, and the decimal point (DP). Pin 1 is listed as "No Connection". This configuration requires the driving circuit to supply current (sink current) to the common anode pins and to draw current (source current) from the individual cathode pins to illuminate the segments.

6. Welding and Assembly Guide

6.1 SMT Welding Instructions

Na'urar an tsara ta don aikin hadin guda na reflux. Iyaka mai mahimmanci ita ce adadin zagayowar aikin reflux dole ne ya zama ƙasa da sau biyu. Idan ana buƙatar reflux na biyu (misali, don haɗa gefe biyu), dole ne a sanyaya allon kewaye zuwa yanayin zafi na yau da kullun tsakanin aikin farko da na biyu.

• Reflow curve (maximum 2 cycles):Preheat to 120-150°C, maximum 120 seconds. Peak temperature must not exceed 260°C.
• Hand soldering (maximum 1 cycle):If using a soldering iron, the tip temperature must not exceed 300°C, and the contact time must be limited to a maximum of 3 seconds.

6.2 Recommended Land Pattern

The land pattern (footprint) for PCB design is provided. Adhering to this pattern is crucial for forming reliable solder joints, ensuring proper alignment, and managing heat during the reflow process.

6.3 Moisture Sensitivity and Storage

元件以防潮包装运输。必须在≤30°C和≤60%相对湿度（RH）下存储。一旦密封袋打开，元件开始从环境中吸收湿气。如果未立即使用且未存储在干燥柜中（<典型为≤10% RH），则必须在回流焊接前进行烘烤，以防止因湿气快速膨胀导致的“爆米花”或分层损坏。

• Baking Conditions:If components are on tape: bake at 60°C for ≥48 hours. If components are in bulk: bake at 100°C for ≥4 hours or at 125°C for ≥2 hours. Baking can be performed only once.

7. Packaging and Ordering Information

7.1 Packaging Specifications

This device is supplied in tape and reel format, suitable for automated surface-mount assembly.

• Reel Dimensions:Provides the dimensions of the component carrier tape and the overall reel (e.g., indicates 13-inch and 22-inch reel options).
• Carrier Tape:Made from black conductive polystyrene alloy. Dimensions comply with the EIA-481-D standard. Carrier tape thickness is 0.30 ±0.05 mm.
• Packaging Quantity:Standard 13-inch reel contains 1000 pieces. The carrier tape length of a 22-inch reel is 56.5 meters. The minimum order quantity for remaining reels is 250 pieces.
• Leader Tape and Trailer Tape:The reel includes a leader tape (minimum 400mm) and a trailer tape (minimum 40mm) for machine feeding.

8. Application Notes and Design Considerations

8.1 Intended Use and Limitations

This display is designed for general electronic equipment in office, communication, and home applications. It is not intended for safety-critical or high-reliability applications where failure could endanger life or health (e.g., aviation, medical systems) without prior consultation and potential certification.

8.2 Key Design Rules

• Drive Circuit Protection:Driver circuitMustIncludes protection against reverse voltage and voltage transients, as these can immediately damage the LED junction.
• Current limiting:Always use a series current-limiting resistor or a constant current driver. Never connect an LED directly to a voltage source. Based on the power supply voltage (V_{Power Supply}), LED forward voltage (V_F~2.6V) and the required forward current (I_F) to calculate the resistance value. Formula: R = (V_{Power Supply}- V_F) / I_F.
• Thermal Management:Adhere to power consumption and current derating rules. Operating at currents or ambient temperatures above recommended limits will accelerate light output attenuation (light decay) and may lead to premature failure. If operating near maximum ratings, ensure the PCB has sufficient copper area or thermal vias.
• Multiplexing:For multi-digit displays using multiplexing, ensure the peak current in pulse mode does not exceed the absolute maximum rating of 60 mA, and calculate the average current to stay within the continuous current rating.

9. Technical Comparison and Differentiation

Compared to older technologies such as GaAsP (Gallium Arsenide Phosphide) red LEDs, the AlInGaP technology employed in the LTS-2807CKD-P offers significantly higher luminous efficacy, thereby achieving higher brightness at the same input current. It also typically provides better wavelength stability over temperature and lifetime. Compared to some white segment displays that use color filters on blue/white LEDs, the monochromatic AlInGaP chip delivers pure color saturation for the target red light and may offer higher efficiency. Compared to through-hole LED displays, its SMD package provides better mechanical robustness and is more suitable for high-volume automated manufacturing.

10. Frequently Asked Questions (FAQ)

10.1 Based on Technical Parameters

Q: When using a 5V power supply, what resistor value should I use?
A: For a typical forward voltage of 2.6V and a desired current of 10 mA, the calculation is as follows: R = (5V - 2.6V) / 0.01A = 240 ohms. Use the nearest standard value (e.g., 240Ω or 220Ω). Be sure to verify the actual current in the circuit.

Q: Can I drive it continuously at 20 mA?
A: Yes, 20 mA is below the maximum of 25 mA at 25°C. However, you must check the ambient temperature. If the operating environment is above 25°C, the current must be derated. At 70°C, the maximum current is 25 mA - (0.28 mA/°C * 45°C) ≈ 12.4 mA.

Q: Since I shouldn't operate it in reverse, why is the reverse current rating important?
A: It is a quality and leakage indicator. A high reverse current may indicate a junction defect. This rating also indicates the required protection level; any reverse bias event exceeding 5V or causing a current over 100 µA will cause damage.

Q: What does "2:1 luminous intensity matching ratio" mean for my design?
A: This means that under the same test conditions, the brightness of the dimmest segment in a digit must not be less than half the brightness of the brightest segment. This ensures visual uniformity. For critical applications, you can select from stricter grades.

11. Practical Application Examples

Scenario: Designing a single-digit temperature readout display for a consumer appliance.
The LTS-2807CKD-P is an ideal choice. The microcontroller (MCU) port pins can sink current (connected to segment cathodes). A PNP transistor or a dedicated driver IC can supply current to the common anode pin. If using a multi-digit display, the MCU firmware must implement a 7-segment decoder and a multiplexing timer. The gray panel/white segments provide excellent contrast against the appliance bezel. Low power consumption meets energy efficiency goals. Designers must ensure the PCB layout includes the recommended pad pattern, incorporates a current-limiting resistor in series with each cathode (or uses a constant-current driver IC), and adheres to the reflow profile guidelines during manufacturing. After the reel is opened, components must be stored in a dry environment until the assembly date.

12. Working Principle

This device operates based on the principle of electroluminescence in a semiconductor P-N junction. When a forward voltage exceeding the junction's built-in potential (approximately 2.0-2.2V for AlInGaP) is applied, electrons from the N-type material and holes from the P-type material are injected into the junction region. They recombine in the active region (the AlInGaP quantum well layer). A portion of the recombination energy is released in the form of photons (light). The specific composition of aluminum, indium, gallium, and phosphorus in the epitaxial layer determines the bandgap energy, which directly defines the wavelength (color) of the emitted light—in this case, ultra-red light at approximately 650 nm. The common anode configuration internally connects the anodes of all LED segments, simplifying the drive circuit by requiring only one current source node per digit.

13. Technology Trends

The use of AlInGaP to manufacture red and amber LEDs represents a mature and highly optimized technology. Current trends in display LEDs focus on several areas: 1)Improving Efficiency:Ongoing research aims to reduce efficiency droop at high currents and improve the light extraction efficiency of chip packaging. 2)Miniaturization:Although 0.2 inches is the standard size, the demand for smaller character heights in ultra-compact devices is growing. 3)Integration:Trends include integrating LED displays with driver ICs and controllers in multi-chip modules or System-in-Package (SiP) solutions to simplify end-product design.4)Enhanced Reliability:Improvements in packaging materials and die-attach technologies continue to drive increases in operational lifetime and tolerance to the higher temperature reflow profiles required for lead-free soldering.