LTS-4801JD LED Digital Tube Datasheet - 0.39 Inch Character Height - AlInGaP Super Red - 2.6V Forward Voltage - 70mW Power Consumption - Technical Documentation

1. Product Overview

LTS-4801JD is a high-performance, single-digit, seven-segment digital display module, specifically designed for applications requiring clear and bright numeric readouts. Its core function is to intuitively display numbers 0-9 and some letters using independently addressable LED segments. The device is designed for reliability and easy integration into various electronic systems.

1.1 Core Advantages and Target Market

This display offers several key advantages and is suitable for a variety of application scenarios. Its main benefits include: excellent character appearance with uniform and continuous segments; high brightness and contrast, ensuring excellent visibility even in bright environments; and a wide viewing angle, guaranteeing clear readability from different positions. Additionally, it features low power consumption and high solid-state reliability, contributing to long life and high energy efficiency. The device is graded by luminous intensity, ensuring consistency in brightness levels. Target markets include industrial control panels, test and measurement equipment, consumer appliances, automotive dashboards (auxiliary displays), and any embedded system requiring compact, reliable digital displays.

2. Detailed Technical Specifications

The performance of the LTS-4801JD is defined by a series of precise electrical and optical parameters, which designers must consider to ensure proper implementation.

2.1 Photometric and Optical Characteristics

Optical performance is at the core of its functionality. The device employs an AlInGaP (Aluminum Indium Gallium Phosphide) ultra-red LED chip. At a forward current (IF) of 1mA, its typical average luminous intensity (Iv) ranges from 200 to 650 microcandelas (μcd). The color is defined by a peak emission wavelength (λp) of 650 nanometers (nm) and a dominant wavelength (λd) of 639 nm, both measured under IF=20mA conditions. The spectral line half-width (Δλ) is 20 nm, indicating a relatively pure red color. The maximum luminous intensity matching ratio between segments is 2:1, ensuring uniform and consistent illumination across the entire digital display.

2.2 Electrical Parameters

Electrical specifications ensure the safe and effective operation of the device. Absolute maximum ratings define the operational limits: power dissipation per segment is 70mW; peak forward current per segment is 90mA (duty cycle 1/10, pulse width 0.1ms); at 25°C, continuous forward current per segment is 25mA, requiring a linear derating of 0.33 mA/°C for each 1°C temperature increase. Maximum reverse voltage per segment is 5V. Under typical operating conditions (Ta=25°C, IF=20mA), forward voltage (VF) per segment ranges from 2.1V to 2.6V. At VR=5V, reverse current (IR) is a maximum of 100 μA.

2.3 Thermal and Environmental Specifications

The operating temperature range of this device is -35°C to +85°C, and the storage temperature range is the same. This broad range makes it suitable for environments with significant temperature variations. The soldering temperature rating specifies that the device can withstand 260°C for 3 seconds at a point 0.116 inches (approximately 2.95 mm) below the mounting reference plane, which is crucial for the assembly process.

3. Grading System Description

The datasheet indicates that the device is "graded by luminous intensity." This means a grading system is applied, most likely based on the average luminous intensity (Iv) measured under standard test conditions (IF=1mA). Grading groups devices with similar light output levels (e.g., 200-350 μcd, 350-500 μcd, 500-650 μcd). This allows designers to select devices with consistent brightness for multi-digit displays or applications requiring strict brightness matching. The maximum luminous intensity matching ratio of 2:1 specified in the datasheet is a guarantee for the performance within a single device, while grading ensures consistency across multiple devices.

4. Performance Curve Analysis

Although the provided datasheet excerpt mentions "Typical Electrical/Optical Characteristics Curves," the typical curves for such devices would graphically present key relationships critical for design.

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The typical I-V curve demonstrates the exponential relationship between forward current (IF) and forward voltage (VF) for an AlInGaP LED chip. The curve begins to conduct noticeably around 1.8V-2.0V and exhibits a relatively steep slope within the normal operating range (e.g., 5-30mA), with VF rising to a typical 2.1V-2.6V at 20mA. This curve is crucial for designing current-limiting circuits.

4.2 Ƙarfin Hasken Haske vs. Madaidaicin Halin Yanzu

This curve is crucial for brightness control. It typically shows that luminous intensity (Iv) increases approximately linearly with forward current (IF) over a considerable range before potentially saturating at extremely high currents. The slope of this line determines efficiency (lumens per watt or candela per ampere). Designers use this curve to select the operating current required to achieve the desired brightness level.

4.3 Luminous Intensity vs. Ambient Temperature

The light output of an LED decreases as its junction temperature rises. The derating curve illustrates the relationship between relative luminous intensity and changes in ambient temperature (Ta) or junction temperature (Tj). For AlInGaP LEDs, the output can decrease significantly with increasing temperature, which must be considered in thermal management and designs for high-temperature environments.

4.4 Spectral Distribution

The spectral power distribution graph will show the relative intensity of light emitted around the 650 nm peak wavelength at different wavelengths. A spectral half-width of 20 nm indicates the width of this peak at half its maximum intensity, confirming the monochromatic nature of the red light.

5. Mechanical and Packaging Information

The physical structure of LTS-4801JD is defined for its mechanical integration.

5.1 Dimensions and Outline Drawing

The character height of this package is 0.39 inches (10.0 mm). The detailed dimension drawing (referenced in the datasheet) specifies the overall package length, width, height, the dimensions and spacing of each segment, the pin pitch and length, and the position of the right-hand decimal point. Unless otherwise noted, all dimensions are in millimeters with a standard tolerance of ±0.25 mm. This drawing is crucial for creating the PCB footprint and ensuring proper fit within the enclosure.

5.2 Pin Definition and Polarity Identification

This device utilizes a 10-pin configuration. It features a common anode architecture, meaning the anodes of all LED segments are internally connected and brought out to specific pins. The pin connections are as follows: Pin 3 and Pin 8 are the common anodes (internally connected). The cathode for each segment is on a separate pin: Pin 1 (Segment G), Pin 2 (Segment F), Pin 4 (Segment E), Pin 5 (Segment D), Pin 6 (DP, Decimal Point), Pin 7 (Segment C), Pin 9 (Segment B), Pin 10 (Segment A). The pin numbering and the location of Pin 1 must be identified from the mechanical drawing. The "Rt. Hand Decimal" note confirms the decimal point is positioned on the right side of the digit.

5.3 Internal Circuit Diagram

The referenced internal circuit diagram visually illustrates the common anode configuration. It will show a common node (anode) connected to the positive supply, while the cathode of each segment's LED (A through G, plus DP) is connected to an individual pin. To illuminate a specific segment, its corresponding cathode pin must be driven low (grounded through a current-limiting resistor), while the common anode is held high.

6. Welding and Assembly Guide

Proper handling is required to maintain device integrity.

6.1 Reflow Soldering Parameters

The key parameter provided is the maximum soldering temperature: 260°C for 3 seconds, measured at a point 0.116 inches (2.95 mm) below the seating plane. This aligns with typical lead-free reflow profiles, such as IPC/JEDEC J-STD-020. A standard reflow profile should be used, including preheat, rapid temperature rise, peak temperature (not exceeding 260°C within the specified time), and controlled cooling zones. The profile must ensure the temperature at the package leads does not exceed the absolute maximum rating.

6.2 Precautions and Operations

Standard ESD (Electrostatic Discharge) precautions must be observed during handling and assembly, as the LED chip is sensitive to static electricity. Avoid applying mechanical stress to the leads or plastic package. Post-soldering cleaning should use methods compatible with the package material (which may be epoxy).

6.3 Storage Conditions

The device should be stored within the specified storage temperature range of -35°C to +85°C. It is recommended to store components in a low-humidity environment and use anti-static packaging until ready for use to prevent moisture absorption and electrostatic damage.

7. Application Recommendations

7.1 Typical Application Circuit

For common anode displays like the LTS-4801JD, the most common driving method is multiplexing, especially when using multiple digits. A microcontroller or dedicated display driver IC powers the common anode for each digit sequentially while outputting the cathode pattern for the segments that should light up on that digit. This method saves I/O pins. For single-digit applications, a simpler static drive can be used: connect the common anode pins (3 and 8) through a current-limiting resistor for the entire display to the positive supply voltage (Vcc), and connect each cathode pin (A-G, DP) to a microcontroller I/O pin or a driver transistor. Each I/O pin requires a current-limiting resistor in series for its corresponding segment.

7.2 Current Limiting Resistor Calculation

The value of the current limiting resistor is crucial. It can be calculated using Ohm's Law: R = (Vcc - VF) / IF. For example, with Vcc at 5V, a typical VF of 2.6V, and a desired IF of 20mA: R = (5V - 2.6V) / 0.020A = 120 ohms. The resistor's power rating should be at least P = (IF)^2 * R = (0.020)^2 * 120 = 0.048W, so a standard 1/8W (0.125W) or 1/4W resistor is sufficient.

7.3 Design Considerations

Brightness Control:Brightness can be adjusted by varying the forward current (IF) within a specified range, for example, by changing the resistance value or using PWM (Pulse Width Modulation) on the drive signal. PWM is very effective for dimming.
Viewing Angle:A broad perspective is beneficial, but when positioning the display in the final product, the primary viewing direction must be considered.
Thermal Management:Although power consumption is low, if using multiple displays or operating in high-temperature environments, ensure sufficient ventilation to prevent luminance degradation and extend service life.
Contrast Enhancement:The gray panel and white segments provide inherent contrast. For optimal readability, a dark bezel or filter can be used around the display, especially under bright ambient light, to further enhance contrast.

8. Technical Comparison and Differentiation

LTS-4801JD primarily achieves differentiation through its adopted AlInGaP technology and specific performance characteristics.

Comparison of AlInGaP with other LED technologies:Compared to traditional GaAsP or GaP red LEDs, AlInGaP LEDs offer significantly higher luminous efficiency (more light output per unit of electrical power), better temperature stability, and a more saturated "super" red color. Compared to new high-power white LEDs that use filters, this device is simpler, requires less complex drive circuitry, and can directly provide pure, efficient red light.

Within the field of seven-segment displays:Its 0.39-inch character height places it in the common size category for panel-mounted meters. Listed key competitive advantages include its continuous uniform segments (neat appearance), high brightness and contrast, and graded luminous intensity (ensuring consistency). Low power requirements are also an advantage for battery-powered devices.

9. Frequently Asked Questions (Based on Technical Parameters)

Q1: Why are there two common anode pins (Pin 3 and Pin 8)?
A1: Using two pins for common connection helps distribute the total anode current (sum of all lit segment currents). This reduces current density on individual pins and PCB traces, improving reliability. They are internally connected, so only one needs to be connected in the circuit, but connecting both is recommended for optimal performance.

Q2: Can I drive this display directly from a 3.3V microcontroller without using current-limiting resistors?
A2: No. You must always use a current-limiting resistor (or constant current source) for each segment. The forward voltage (VF) is typically 2.1V-2.6V. Connecting 3.3V directly from a microcontroller pin to the LED would attempt to drive an uncontrolled, potentially destructive current through the LED, as the only resistance would be the very low internal resistance of the MCU pin and the LED.

Q3: What does "Continuous forward current linearly derated from 25°C" mean?
A3: This means that when the ambient temperature exceeds 25°C, the maximum allowable continuous forward current decreases. The derating factor is 0.33 mA/°C. For example, at 50°C (25°C above the reference temperature), the maximum current will be 25mA - (0.33 mA/°C * 25°C) = 25mA - 8.25mA = 16.75mA. This prevents overheating and ensures reliability.

Q4: How to understand the 2:1 luminous intensity matching ratio?
A4: This means that within a single LTS-4801JD unit, when measured under the same conditions (IF=1mA), the brightness of the dimmest segment is not less than half the brightness of the brightest segment. This ensures visual uniformity across the entire numeric display.

10. Practical Design and Usage Cases

Case: Designing a Simple Digital Voltmeter Reading Display
A designer is creating a compact digital voltmeter to display 0.0V to 19.9V. They need a clear, low-power display. They selected the LTS-4801JD for its high brightness and 0.39-inch size, which is clear and readable for the intended use. Three displays are used to show three digits. The microcontroller's ADC reads the voltage, converts it to a numerical value, and drives the displays via a multiplexing scheme, using a transistor array to control the common anodes and the MCU's I/O pins (with series resistors) to control the segment cathodes. The right decimal point of the middle digit is used to display the tenths place. AlInGaP red was chosen for its high contrast on dark panels. The designer calculated resistor values for the 5V system to drive each segment at approximately 15mA, providing ample brightness while staying well below the 25mA continuous rating at room temperature.

11. Introduction to Working Principles

LTS-4801JD yana aiki bisa ga ka'idar haske ta lantarki a cikin kayan semiconductor. Tsarin guntu na AlInGaP yana samar da haɗin p-n. Lokacin da ake amfani da ƙarfin lantarki mai kyau wanda ya wuce kofa (kusan 1.8-2.0V), electrons daga yankin n-type da ramuka daga yankin p-type ana shigar da su cikin yanki mai aiki, kuma a can suke haɗuwa. A cikin AlInGaP, wannan haɗuwa yana sakin makamashi galibi a cikin nau'in photons (haske) na kewayon tsayin rawaya (kusan 650 nm). Kowane ɓangare bakwai (A zuwa G) da ma'auni (DP) sun ƙunshi ɗaya ko fiye da ƙananan guntu na LED da aka saka a cikin kunsa. Tsarin anode gama gari yana sauƙaƙa da'irar tuƙi ta waje ta hanyar ba da damar tushen ƙarfin lantarki guda ɗaya don samar da duk sassan, kuma ta hanyar sanya cathode na sashen da ake buƙata a ƙasa don sarrafa su daban.

12. Technical Trends and Background

Masu nuna LED bakwai kamar LTS-4801JD suna wakiltar fasahar nuni mai cikakkiyar ci gaba da ingantacciya. Kodayake sabbin fasahohi kamar matrix OLED ko TFT LCD suna ba da sassauci mafi girma (cikakken zane, launi da yawa), LED bakwai suna ci gaba da riƙe fa'idodi masu ƙarfi a wasu fagage: da'irar tuƙi mai sauƙi sosai, haske da bambanci sosai, karantawa mai kyau a cikin hasken rida, fadin yanayin zafi na aiki, da ingantaccen dogon lokaci aminci (babu gazawar baya). Trends a cikin wannan fanni shine yin amfani da ci-gaban kayan semiconductor kamar AlInGaP kamar yadda aka nuna a wannan na'urar don samun ingantacciyar inganci (lumens da yawa kowace watt), da kuma amfani da kunsan kayan aiki don haɗawa ta atomatik. Don aikace-aikacen da babban buƙatunsu shine nuna lambobi masu tsada, ƙarfi, da saukin karantawa, har yanzu su ne zaɓin mafita.