LTS-4801JF 0.4-inch Yellow-Orange LED Display Datasheet - Digit Height 10mm - Forward Voltage 2.6V - Power 70mW - English Technical Document

1. Product Overview

The LTS-4801JF is a high-performance, single-digit, seven-segment alphanumeric display module designed for applications requiring clear, bright numeric indication. Its core function is to visually represent the digits 0-9 and some letters using individually addressable LED segments. The device is engineered for reliability and ease of integration into various electronic systems.

The primary application of this display is in instrumentation panels, test equipment, industrial controls, consumer appliances, and any device where a compact, highly readable numeric readout is necessary. Its design prioritizes clarity and longevity, making it suitable for both commercial and industrial environments.

1.1 Core Advantages and Target Market

The display offers several key advantages that differentiate it in the market. It features a 0.4-inch (10 mm) digit height, which provides an excellent balance between size and readability. The segments are continuous and uniform, ensuring a consistent and professional appearance when illuminated. A major benefit is its low power requirement, which makes it ideal for battery-powered or energy-efficient devices.

Furthermore, it delivers high brightness and high contrast, ensuring visibility even in well-lit conditions. The wide viewing angle allows the display to be read from various positions without significant loss of clarity. Built with solid-state reliability, it offers a long operational life with minimal maintenance. The device is also categorized for luminous intensity, providing consistency in brightness levels across production batches. The target market includes designers of portable devices, panel meters, medical equipment, and automotive dashboards where space, power consumption, and reliability are critical factors.

2. Technical Specifications Deep Dive

This section provides a detailed, objective analysis of the device's technical parameters as defined in the datasheet.

2.1 Photometric and Optical Characteristics

The optical performance is central to the display's functionality. The device utilizes AlInGaP (Aluminum Indium Gallium Phosphide) semiconductor material to produce a yellow-orange emission. The typical peak emission wavelength (λp) is 611 nm when driven at a forward current (IF) of 20 mA. The dominant wavelength (λd) is specified at 605 nm, defining the perceived color. The spectral line half-width (Δλ) is 17 nm, indicating a relatively pure color emission with minimal spectral spread.

The average luminous intensity (Iv) per segment is a key parameter. Under a standard test condition of IF=1mA, the intensity ranges from a minimum of 200 μcd to a typical value of 650 μcd. The luminous intensity matching ratio between segments is specified at a maximum of 2:1, ensuring uniform brightness across the digit for a cohesive appearance. The gray face with white segments enhances contrast when the LEDs are off, contributing to the excellent character appearance mentioned in the features.

2.2 Electrical Parameters

The electrical specifications define the operating limits and conditions for the device. The absolute maximum ratings must not be exceeded to prevent permanent damage. The maximum power dissipation per segment is 70 mW. The peak forward current per segment is 60 mA, but this is only permissible under pulsed conditions (1/10 duty cycle, 0.1ms pulse width). The continuous forward current per segment is rated at 25 mA at 25°C, with a derating factor of 0.33 mA/°C as the ambient temperature increases. The maximum reverse voltage per segment is 5 V.

Under typical operating conditions (Ta=25°C, IF=20mA), the forward voltage (Vf) per segment ranges from 2.05V to 2.6V. The reverse current (Ir) is a maximum of 100 μA when a reverse voltage (Vr) of 5V is applied. These parameters are crucial for designing the appropriate current-limiting circuitry and ensuring stable operation over the device's lifetime.

2.3 Thermal and Environmental Specifications

The device is rated for an operating temperature range of -35°C to +85°C and a storage temperature range of -35°C to +85°C. This wide range makes it suitable for applications in harsh environments. The derating of the continuous forward current with temperature (0.33 mA/°C) is a critical design consideration to prevent overheating and ensure longevity. The datasheet also specifies a soldering temperature profile: the device can withstand 260°C for 3 seconds at a point 1/16 inch below the seating plane. Adhering to this guideline is essential during the PCB assembly process to avoid thermal damage to the LED chips or the package.

3. Binning System Explanation

The datasheet indicates that the device is \"categorized for luminous intensity.\" This refers to a common practice in LED manufacturing known as binning. Due to inherent variations in the semiconductor fabrication process, LEDs from the same production batch can have slight differences in key parameters like luminous intensity, forward voltage, and dominant wavelength.

To ensure consistency for the end-user, manufacturers measure these parameters and sort the LEDs into different \"bins.\" The LTS-4801JF is binned specifically for luminous intensity (Iv). This means that within a single order or reel, the brightness of the segments will fall within a predefined, narrow range (as suggested by the 2:1 matching ratio). This eliminates large variations in brightness between different units in an application, which is vital for multi-digit displays or products where visual uniformity is important. The datasheet provides the min/typ/max values (200/650 μcd), but specific bin codes for tighter groupings would typically be available from the manufacturer upon request.

4. Performance Curve Analysis

While the specific graphs are not detailed in the provided text, typical characteristic curves for such a device would be essential for in-depth design analysis. These usually include:

• Relative Luminous Intensity vs. Forward Current (I-V Curve): This graph shows how the light output increases with the driving current. It is typically non-linear, with efficiency dropping at very high currents due to heating effects. Designers use this to select an optimal operating point that balances brightness with power consumption and lifespan.
• Forward Voltage vs. Forward Current: This curve is vital for designing the driver circuit. It shows the voltage drop across the LED for a given current, confirming the Vf specifications and helping to calculate power dissipation.
• Relative Luminous Intensity vs. Ambient Temperature: This graph illustrates how light output decreases as the junction temperature of the LED increases. It underscores the importance of thermal management, especially when operating at high currents or in elevated ambient temperatures.
• Spectral Distribution: A plot of relative intensity versus wavelength, showing the peak at ~611 nm and the shape of the emission spectrum, confirming the color purity indicated by the spectral half-width.

These curves allow engineers to predict performance under non-standard conditions and optimize their designs for reliability and efficiency.

5. Mechanical and Packaging Information

The device's physical construction is defined by its package dimensions. The datasheet includes a detailed dimensional drawing (all dimensions in millimeters with a general tolerance of ±0.25mm unless noted). Key features include the overall length, width, and height of the package, the spacing between the pins, and the position of the decimal point (noted as \"Rt. Hand Decimal\" in the part description).

The pin connection diagram is crucial for correct PCB layout. The LTS-4801JF is a common anode device. The internal circuit diagram shows that all anodes for the segments are connected together internally to two pins (pin 3 and pin 8, which are common). The cathodes for each segment (A, B, C, D, E, F, G, and the Decimal Point) are brought out to individual pins (1, 2, 4, 5, 6, 7, 9, 10 respectively). Pin 6 is specifically for the decimal point cathode. This configuration requires a current-sinking driver circuit, where the common anode(s) are connected to a positive supply voltage, and the individual segment cathodes are pulled low (sunk to ground) through current-limiting resistors to turn them on.

6. Soldering and Assembly Guidelines

Proper handling during assembly is critical. The absolute maximum rating specifies the soldering condition: the device can withstand a temperature of 260°C for 3 seconds, measured 1/16 inch (approximately 1.6 mm) below the seating plane. This is a standard reflow soldering profile. It is imperative to follow this guideline to prevent thermal shock, which can damage the internal wire bonds, degrade the LED chip, or delaminate the package.

General recommendations include: using a controlled reflow oven with a validated temperature profile; avoiding hand soldering directly to the device pins if possible; ensuring the PCB is clean and free of contaminants; and following standard ESD (Electrostatic Discharge) precautions during handling, as LEDs are sensitive to static electricity. For storage, the specified range is -35°C to +85°C in a dry, anti-static environment.

7. Packaging and Ordering Information

The base part number is LTS-4801JF. The \"JF\" suffix may indicate specific characteristics like color (yellow-orange) and package type. While not detailed in this excerpt, typical packaging for such components would be on anti-static tape and reel, suitable for automated pick-and-place assembly machines. The reel quantity (e.g., 1000 pieces, 2000 pieces) would be defined by the manufacturer. For ordering, engineers must specify the full part number. If the manufacturer offers different bins for luminous intensity or forward voltage, additional binning codes might be appended to the part number (e.g., LTS-4801JF-XXX). It is essential to consult the manufacturer's full product guide or distributor for the complete ordering options and packaging specifications.

8. Application Suggestions

8.1 Typical Application Scenarios

The LTS-4801JF is ideal for any application requiring a single, highly legible digit. Common uses include: panel meters for voltage, current, or temperature; timer and counter displays; scoreboards; appliance control panels (e.g., ovens, microwaves); test and measurement equipment; and status indicators on industrial machinery. Its low power consumption makes it a candidate for portable, battery-operated devices.

8.2 Design Considerations and Circuitry

When designing with this display, several factors must be considered. First, an appropriate current-limiting resistor must be calculated for each segment (or a single resistor on the common anode if uniform brightness is acceptable) based on the desired forward current (e.g., 10-20 mA) and the supply voltage. The formula is R = (V_supply - Vf_LED) / I_LED. Using the maximum Vf (2.6V) ensures the resistor is not under-sized.

Second, the driver circuit must be capable of sinking the total current for all illuminated segments. If all segments plus the decimal point are on (displaying the digit '8.'), the common anode pin must supply up to 9 * I_LED. The driver IC (like a microcontroller GPIO pin or a dedicated display driver) must have sufficient current sinking capability for the cathode pins. Multiplexing is not required for a single digit, but for multi-digit designs using similar displays, a multiplexing scheme would be necessary to control multiple digits with fewer I/O pins. Heat dissipation should be considered if operating near the maximum continuous current, especially in high ambient temperatures.

9. Technical Comparison and Differentiation

Compared to older technologies like incandescent or vacuum fluorescent displays (VFDs), the LTS-4801JF offers significant advantages: much lower power consumption, longer lifespan (solid-state reliability), faster response time, and greater resistance to shock and vibration. Compared to other LED technologies, the use of AlInGaP material provides high efficiency and excellent color stability for red, orange, and yellow colors, often with better performance in high-temperature environments than some earlier LED materials.

Within the category of seven-segment displays, its key differentiators are the specific 0.4-inch digit height, the yellow-orange color, the common anode configuration, the inclusion of a right-hand decimal point, and its categorization for luminous intensity consistency. Designers would compare it to other sizes (0.3\", 0.5\", 0.56\"), colors (red, green, blue), configurations (common cathode), and brightness grades to select the optimal part for their application.

10. Frequently Asked Questions (Based on Technical Parameters)

Q: What is the purpose of the two common anode pins (3 and 8)?
A: They are internally connected. Having two pins helps distribute the total anode current, reduces current density in a single pin, improves reliability, and can aid in PCB layout for power routing.

Q: Can I drive this display directly from a 5V microcontroller pin?
A: No. You must use a current-limiting resistor in series with each segment cathode. Connecting directly would likely exceed the maximum forward current and destroy the LED segment. Calculate the resistor value based on your supply voltage (e.g., 5V), the LED forward voltage (~2.6V), and your desired current (e.g., 15 mA).

Q: What does \"luminous intensity matching ratio 2:1\" mean?
A> It means that the dimmest segment in a device will be no less than half as bright as the brightest segment under the same test conditions. This ensures visual uniformity across the digit.

Q: How do I interpret the forward current derating?
A> The continuous forward current rating of 25 mA is valid at 25°C ambient. For every degree Celsius above 25°C, you must reduce the maximum allowable continuous current by 0.33 mA to prevent overheating. For example, at 50°C ambient, the max current would be 25 mA - (0.33 mA/°C * 25°C) = 16.75 mA.

11. Practical Design and Usage Example

Consider designing a simple battery-powered digital thermometer that displays temperature to one decimal place. The microcontroller reads a temperature sensor, processes the data, and needs to drive a single-digit display for the whole number and a decimal point. The LTS-4801JF is a suitable choice.

The design steps would include: 1) Assigning microcontroller GPIO pins to each segment cathode (A-G) and the decimal point cathode (DP). 2) Connecting the two common anode pins (3 & 8) to the positive supply rail (e.g., 3.3V or 5V) through a single current-limiting resistor if uniform brightness is acceptable, or individual resistors per segment for precise control. 3) Calculating the resistor value. For a 3.3V supply, target current of 10mA, and Vf of 2.6V: R = (3.3V - 2.6V) / 0.01A = 70 Ohms. A standard 68 or 75 Ohm resistor would be used. 4) Writing firmware to convert the temperature value (e.g., \"25.7\") into the correct pattern of segment activations to display \"5\" and illuminate the decimal point. The common anode is always powered, and the microcontroller sinks current to ground on the cathodes corresponding to the segments needed to form the digit \"5\" (segments A, C, D, F, G) and the DP cathode.

12. Technology Principle Introduction

The LTS-4801JF is based on Light Emitting Diode (LED) technology. An LED is a semiconductor p-n junction diode. When a forward voltage is applied, electrons from the n-type region and holes from the p-type region are injected into the junction region. When these charge carriers recombine, they release energy in the form of photons (light). The color of the light is determined by the energy bandgap of the semiconductor material.

This specific device uses AlInGaP (Aluminum Indium Gallium Phosphide) material grown on a non-transparent Gallium Arsenide (GaAs) substrate. AlInGaP has a bandgap suitable for emitting light in the red to yellow-orange spectrum. The \"non-transparent\" substrate helps improve contrast by absorbing stray light, contributing to the high contrast ratio mentioned in the features. Each segment of the digit contains one or more tiny AlInGaP LED chips. The gray face and white segments are part of the plastic package, which acts as a diffuser and lens to shape the light output for optimal visibility and viewing angle.

13. Technology Trends and Developments

The field of display technology is continuously evolving. While traditional seven-segment LED displays like the LTS-4801JF remain highly relevant for their simplicity, reliability, and cost-effectiveness in numeric display applications, broader trends are evident. There is a general move towards higher integration, such as displays with built-in controllers (I2C or SPI interfaces) that simplify the microcontroller interface and reduce the number of required I/O pins.

In terms of materials, while AlInGaP is excellent for red/orange/yellow, other materials like InGaN (Indium Gallium Nitride) dominate the blue and green spectrum and are used in white LEDs. Research continues into improving efficiency (lumens per watt), color rendering, and lifetime across all LED colors. For seven-segment applications specifically, the trends focus on achieving even lower power consumption for IoT devices, higher brightness for sunlight-readable applications, and thinner packages for sleeker product designs. However, the fundamental principle and application of discrete seven-segment displays as a robust, easily understood human-machine interface continue to be a staple in electronic design.