LTS-6980HR LED Display Datasheet - 0.56 Inch Digit Height - 2.6V Forward Voltage - Red Color - English Technical Document

1. Product Overview

The LTS-6980HR is a high-performance, seven-segment numeric LED display module. Its primary function is to provide clear, bright numeric readouts in a variety of electronic equipment. The core technology utilizes advanced LED chips, specifically GaP epi on GaP substrate and AlInGaP on a non-transparent GaAs substrate, to achieve its characteristic high-efficiency red emission. The device features a red face and red segments, ensuring excellent contrast and visibility.

1.1 Key Features and Advantages

The display is designed with several key features that make it suitable for demanding applications:

• 0.56 Inch Digit Height (14.22 mm): Provides a character size that is easily readable from a distance, making it ideal for instrumentation panels, industrial controls, and consumer electronics.
• Continuous Uniform Segments: The segments are designed for visual consistency, eliminating gaps or irregularities that can impair readability.
• Low Power Requirement: Engineered for efficiency, it allows for integration into battery-powered or energy-conscious devices.
• High Brightness & High Contrast: The combination of bright red emission and a red face creates a high-contrast display that remains visible under various ambient lighting conditions.
• Wide Viewing Angle: The optical design ensures that the displayed characters remain legible even when viewed from off-axis angles.
• Solid-State Reliability: As an LED-based device, it offers long operational life, shock resistance, and vibration tolerance compared to other display technologies.
• Categorized for Luminous Intensity: Devices are binned according to their light output, allowing designers to select units with consistent brightness for multi-digit displays.
• Lead-Free Package (RoHS Compliant): Manufactured in compliance with environmental regulations, making it suitable for global markets.

1.2 Device Configuration

The LTS-6980HR is configured as a common cathode display. This means the cathodes of all the LED segments are connected together internally. The specific part number denotes a red display with a right-hand decimal point. Driving a common cathode display typically requires connecting the common cathode pin(s) to ground and applying a positive voltage (through a current-limiting resistor) to the individual anode pins corresponding to the segments to be illuminated.

2. Technical Parameters: In-Depth Objective Analysis

This section provides a detailed, objective breakdown of the device's operational limits and performance characteristics. Understanding these parameters is critical for reliable circuit design and ensuring the display operates within its specified lifetime.

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 normal use.

• Power Dissipation per Segment: 75 mW maximum. Exceeding this can lead to overheating and accelerated degradation of the LED chip.
• Peak Forward Current per Segment: 100 mA under pulsed conditions (1/10 duty cycle, 0.1ms pulse width). This rating is for brief, high-current pulses used in multiplexing schemes, not for continuous operation.
• Continuous Forward Current per Segment: 25 mA at 25°C. This current derates linearly at a rate of 0.33 mA/°C as ambient temperature (Ta) increases above 25°C. For example, at 85°C, the maximum allowable continuous current would be approximately: 25 mA - ((85°C - 25°C) * 0.33 mA/°C) ≈ 5.2 mA.
• Operating & Storage Temperature Range: -35°C to +85°C. The device can be stored or operated within this full range.
• Solder Condition: The device can withstand wave soldering with the solder bath 1/16 inch (≈1.6mm) below the seating plane for 3 seconds at 260°C. The temperature of the device body itself must not exceed the maximum temperature rating during assembly.

2.2 Electrical and Optical Characteristics

These are the typical performance parameters measured under standard test conditions (Ta=25°C). They define how the device will behave in a properly designed circuit.

• Average Luminous Intensity (Iv): Ranges from 800 µcd (minimum) to 2400 µcd (typical) when driven at a forward current (IF) of 10 mA. This is the primary measure of brightness.
• Peak Emission Wavelength (λp): Typically 635 nm at IF=20mA. This is the wavelength at which the optical output power is greatest.
• Spectral Line Half-Width (Δλ): Typically 40 nm. This indicates the spectral purity; a narrower half-width means a more monochromatic (pure color) light.
• Dominant Wavelength (λd): Typically 623 nm. This is the single wavelength perceived by the human eye that best matches the color of the light.
• Forward Voltage per Segment (VF): Ranges from 2.0 V (minimum) to 2.6 V (typical) at IF=20mA. Designers must ensure the driving circuit can provide sufficient voltage to achieve the desired current across this range. A tolerance of ±0.1V is noted.
• Reverse Current per Segment (IR): Maximum 100 µA when a reverse voltage (VR) of 5V is applied. This parameter is for test purposes only; the device is not designed for continuous reverse bias operation.
• Luminous Intensity Matching Ratio (Iv-m): Maximum 2:1 between segments at IF=10mA. This ensures uniformity in brightness across all segments of a single digit.
• Cross Talk: Specified as ≤ 2.5%. This refers to unwanted illumination of a segment due to electrical leakage or optical coupling when an adjacent segment is driven.

3. Binning System Explanation

The datasheet indicates that the devices are categorized for luminous intensity. This is a critical quality control and design consideration. In LED manufacturing, there are natural variations in output. To ensure consistency in end products, LEDs are tested and sorted into different "bins" based on specific parameters.

For the LTS-6980HR, the primary binning criterion is luminous intensity (Iv). When designing an application that uses two or more of these displays together (e.g., a multi-digit counter), it is highly recommended to select displays from the same intensity bin. Using displays from different bins can result in noticeable differences in brightness between digits, leading to an uneven and unprofessional appearance. Designers should consult with their supplier to specify bin requirements for their orders to avoid this "hue uneven" problem, as cautioned in the application notes.

4. Performance Curve Analysis

While the specific graphs are not detailed in the provided text, typical performance curves for such a device would include:

• Forward Current vs. Forward Voltage (I-V Curve): This non-linear curve shows the relationship between the voltage applied across the LED and the resulting current. It is essential for selecting the appropriate current-limiting resistor value.
• Luminous Intensity vs. Forward Current (I-L Curve): This shows how light output increases with drive current. It is generally linear over a range but will saturate at high currents.
• Luminous Intensity vs. Ambient Temperature: This curve demonstrates how light output decreases as the junction temperature of the LED rises. It highlights the importance of thermal management, especially when operating at high currents or in warm environments.
• Spectral Power Distribution: A graph showing the relative optical power emitted across the wavelength spectrum, centered around the dominant and peak wavelengths.

These curves allow designers to predict performance under non-standard conditions (different currents, temperatures) and optimize their design for efficiency and longevity.

5. Mechanical and Packaging Information

5.1 Package Dimensions and Tolerances

The display has a defined physical footprint. Key dimensional notes include:

• All dimensions are in millimeters.
• General tolerance is ±0.25 mm unless otherwise specified.
• Pin tip shift tolerance is ±0.4 mm.
• Specific quality controls are in place for the display face: foreign material on a segment must be ≤10 mils, ink contamination on the surface ≤20 mils, and bubbles within a segment ≤10 mils.
• Reflector bending must be ≤ 1% of its length.
• A printed circuit board (PCB) hole diameter of 1.0 mm is recommended for the pins.

5.2 Pin Configuration and Circuit Diagram

The device has a standard 10-pin single-row configuration. The internal circuit diagram shows a common cathode architecture. The pinout is as follows:

• Pin 1: Anode for segment E
• Pin 2: Anode for segment D
• Pin 3: Common Cathode 1
• Pin 4: Anode for segment C
• Pin 5: Anode for Right-Hand Decimal Point (R.D.P.)
• Pin 6: Anode for segment B
• Pin 7: Anode for segment A
• Pin 8: Common Cathode 2
• Pin 9: Anode for segment F
• Pin 10: Anode for segment G

Both common cathode pins (3 and 8) are internally connected. Connecting either or both to ground will enable the display.

6. Soldering, Assembly, and Storage Guidelines

6.1 Soldering and Assembly

The maximum solder reflow condition is specified. During assembly:

• Avoid using unsuitable tools or methods that apply abnormal force to the display body, as this can cause physical damage.
• If a decorative film or overlay is applied to the display surface using pressure-sensitive adhesive, it is not recommended to let this film side be in close contact with the front panel or cover. External force could cause the film to shift from its original position.

6.2 Storage Conditions

Proper storage is essential to prevent degradation, particularly oxidation of the pins.

• Standard Storage (in original packaging): Temperature: 5°C to 30°C. Humidity: Below 60% RH.
• If these conditions are not met, pin oxidation may occur, requiring re-plating before use. Long-term storage of large inventories is discouraged.
• If the moisture-barrier bag is opened for more than 6 months, it is recommended to bake the devices at 60°C for 48 hours and complete assembly within one week.

7. Application Recommendations and Design Considerations

The LTS-6980HR is intended for ordinary electronic equipment in office, communication, and household applications. For applications requiring exceptional reliability where failure could jeopardize safety (aviation, medical, etc.), specific consultation is advised.

7.1 Circuit Design Best Practices

• Adhere to Absolute Maximum Ratings: Circuit design must strictly respect the limits for current, power, and temperature.
• Prevent Over-Driving: Excess current or high operating temperature will cause severe light output degradation or premature failure.
• Protect Against Reverse Voltage and Transients: The driving circuit should include protection (e.g., diodes) to prevent damage from reverse voltages or voltage spikes during power-up/shutdown.
• Use Constant Current Driving: This is the recommended method to ensure consistent luminous intensity and color, independent of variations in forward voltage.
• Account for Forward Voltage Range: The circuit must be designed to deliver the intended drive current even when the LED's VF is at the maximum specified value (2.6V typical + tolerance).
• Thermal Derating: The chosen operating current must be safe for the maximum expected ambient temperature, considering the current derating factor of 0.33 mA/°C.
• Avoid Reverse Bias: Even small reverse biases can cause metal migration within the LED chip, increasing leakage current or causing a short circuit.
• Manage Environmental Conditions: Avoid rapid temperature changes in high-humidity environments to prevent condensation from forming on the display.

7.2 Typical Application Scenarios

This display is well-suited for a wide range of applications requiring clear, reliable numeric indication, including but not limited to:

• Test and measurement equipment (multimeters, frequency counters)
• Industrial control panels and process timers
• Consumer appliances (microwaves, ovens, audio equipment)
• Point-of-sale terminals and calculators
• Automotive aftermarket gauges and displays

8. Technical Comparison and Differentiation

While a direct comparison with specific competitor parts is not provided in the datasheet, the LTS-6980HR's specifications position it competitively. Its key differentiators likely include:

• Material Technology: The use of both GaP and AlInGaP chip technologies can offer a balance of performance, potentially providing good efficiency and a desirable red color point.
• High Brightness & Contrast: The specified luminous intensity range (up to 2400 µcd @10mA) and red-on-red design are aimed at applications requiring excellent visibility.
• Robust Construction and Specifications: Detailed ratings for power, current derating, and environmental tolerance suggest a design focused on reliability.
• Comprehensive Application Guidance: The inclusion of detailed cautions and storage guidelines assists designers in implementing the device correctly, potentially reducing field failures.

9. Frequently Asked Questions (Based on Technical Parameters)

Q1: What is the difference between Peak Wavelength (635nm) and Dominant Wavelength (623nm)?
A1: Peak wavelength is where the optical power is physically highest. Dominant wavelength is a calculated value based on human color perception (CIE standard) that best represents the color we see. It's common for them to differ slightly.

Q2: Can I drive this display with a 5V microcontroller pin directly?
A2: No. You must use a current-limiting resistor in series with each segment anode. The value depends on your supply voltage (e.g., 5V), the LED's forward voltage (~2.0-2.6V), and your desired forward current (e.g., 10-20mA). For example, at 5V, 2.3V Vf, and 15mA: R = (5V - 2.3V) / 0.015A ≈ 180 Ω.

Q3: Why are there two common cathode pins (3 and 8)?
A3> They are internally connected. This design allows for more flexible PCB layout routing or can be used to split the ground current if driving all segments at once with high current, potentially improving performance.

Q4: What does "Luminous Intensity Matching Ratio ≤ 2:1" mean?
A4: It means that within a single device, the brightest segment will be no more than twice as bright as the dimmest segment when driven under the same conditions. This ensures uniformity.

Q5: How critical is the storage humidity specification?
A5> Very critical for long-term storage. Exposure to high humidity can lead to oxidation of the tin-plated pins, resulting in poor solderability. Following the storage and baking recommendations is essential for reliable assembly.

10. Design and Usage Case Study

Scenario: Designing a 4-Digit Voltmeter Display.
A designer is creating a benchtop digital voltmeter. They select four LTS-6980HR displays. Key design steps based on this datasheet would include:

1. Drive Method: To minimize microcontroller I/O pins, they choose multiplexing. They connect all corresponding segment anodes (A, B, C...) of the four displays together. Each display's common cathode pins are connected to a separate transistor controlled by the MCU.
2. Current Calculation: For good visibility, they target 15mA per segment. Using the maximum Vf of 2.6V and a 5V supply, they calculate the worst-case current-limiting resistor: R_min = (5V - 2.6V) / 0.015A ≈ 160 Ω. They choose a standard 150 Ω resistor, knowing the actual current will vary slightly with Vf.
3. Peak Current Check: In a multiplexed design, each digit is only on for 1/4 of the time (25% duty cycle). To achieve an average current of 15mA, the peak current during its ON time must be 15mA / 0.25 = 60mA. They must verify this 60mA pulse is within the 100mA peak current rating and that the duty cycle is ≤10% if approaching 100mA.
4. Thermal Consideration: The enclosure is expected to reach 50°C max. The derated continuous current per segment is: 25 mA - ((50°C - 25°C) * 0.33 mA/°C) ≈ 16.75 mA. Their design current of 15mA (average) is safe.
5. Procurement: They specify to their supplier that all four displays must be from the same luminous intensity bin to ensure uniform brightness across the readout.
6. PCB Layout: They use the recommended 1.0mm holes for the pins and ensure the layout does not put mechanical stress on the display body.

11. Operating Principle

The LTS-6980HR operates on the fundamental principle of electroluminescence in semiconductor materials. When a sufficient forward voltage is applied across the p-n junction of an LED chip (exceeding its bandgap voltage), electrons and holes recombine in the active region, releasing energy in the form of photons (light). The specific color (wavelength) of the emitted light is determined by the bandgap energy of the semiconductor material. In this device, GaP and AlInGaP materials are used to produce red light. The seven segments are individual LEDs arranged in a figure-eight pattern. By selectively applying current to different combinations of these segments, the numerals 0-9 and some letters can be formed.

12. Technology Trends and Context

The LTS-6980HR represents a mature and reliable segment display technology. In the broader context of display technology trends:

• Solid-State Advantage: LED displays continue to hold advantages in environments requiring robustness, wide temperature operation, and long life, compared to LCDs or VFDs.
• Material Evolution: The use of AlInGaP represents an advancement over older GaAsP LEDs, offering higher efficiency and better color stability.
• Market Niche: While dot-matrix OLEDs and LCDs offer greater flexibility for graphics and alphanumerics, 7-segment LED displays remain the optimal choice for dedicated numeric readouts due to their simplicity, high brightness, low cost, and excellent readability in direct sunlight or dark conditions.
• Integration Trends: There is a trend towards surface-mount device (SMD) versions of such displays for automated assembly. The through-hole design of the LTS-6980HR is suited for applications where manual assembly or repair is common, or where higher power handling is needed.
• Driver Integration: Modern designs often pair discrete displays like this with dedicated LED driver ICs that handle multiplexing, current regulation, and interfacing, simplifying the microcontroller software and hardware design.