LTS-6780JD LED Display Datasheet - 0.56-inch Digit Height - Hyper Red (650nm) - 2.6V Forward Voltage - 70mW Power Dissipation - English Technical Documentation

1. Product Overview

The LTS-6780JD is a single-digit, seven-segment LED display designed for numeric character presentation. It features a digit height of 0.56 inches (14.22 mm), making it suitable for applications requiring medium-sized, highly legible numerals. The device utilizes AlInGaP (Aluminum Indium Gallium Phosphide) semiconductor technology to produce a hyper red emission, characterized by high brightness and excellent color purity. The display has a gray face with white segments, providing high contrast for optimal readability under various lighting conditions. Its primary target markets include industrial control panels, test and measurement equipment, consumer electronics, and instrumentation where reliable, low-power numeric indication is required.

1.1 Core Features and Advantages

• 0.56-Inch Digit Height: Offers a balanced size for good visibility without excessive power consumption.
• Continuous Uniform Segments: Ensures consistent illumination across each segment for a professional appearance.
• Low Power Requirement: Efficient AlInGaP technology enables bright output at relatively low drive currents.
• High Brightness & High Contrast: The hyper red emission against a gray background delivers superior legibility.
• Wide Viewing Angle: Allows the display to be read clearly from off-axis positions.
• Solid-State Reliability: LEDs offer long operational life and resistance to shock and vibration compared to filament-based displays.
• Categorized for Luminous Intensity: Devices are binned for consistent brightness levels.
• Lead-Free Package (RoHS Compliant): Manufactured in accordance with environmental regulations.

1.2 Device Identification

The part number LTS-6780JD specifically denotes a common cathode configuration with a right-hand decimal point (D.P.). The use of AlInGaP hyper red LED chips, fabricated on a non-transparent GaAs substrate, is central to its performance characteristics.

2. Technical Parameters: In-Depth Objective Interpretation

2.1 Absolute Maximum Ratings

These ratings define the stress limits beyond which permanent damage to the device may occur. They are not intended for normal operation.

• Power Dissipation per Segment: 70 mW. This is the maximum power that can be safely dissipated as heat by a single LED segment.
• Peak Forward Current per Segment: 90 mA. This is permissible only under pulsed conditions (1/10 duty cycle, 0.1ms pulse width) to limit average heating.
• Continuous Forward Current per Segment: 25 mA at 25°C. This current derates linearly by 0.28 mA/°C as ambient temperature (Ta) increases above 25°C. For example, at 85°C, the maximum continuous current would be approximately: 25 mA - ((85°C - 25°C) * 0.28 mA/°C) = 8.2 mA.
• Operating & Storage Temperature Range: -35°C to +105°C. The device can withstand these extreme temperatures during both operation and non-operational storage.
• Soldering Conditions: Leads can be soldered at a maximum of 260°C for up to 5 seconds, with the condition that the body temperature of the component does not exceed its maximum rating.

2.2 Electrical & Optical Characteristics

These are the typical performance parameters measured at an ambient temperature (Ta) of 25°C under specified test conditions.

• Average Luminous Intensity (I_V): Ranges from 320 μcd (min) to 808 μcd (typ) at I_F=1mA. At I_F=10mA, the intensity is typically 9750-10500 μcd. This parameter is measured using a sensor filtered to match the human eye's photopic response (CIE curve).
• Peak Emission Wavelength (λ_p): 650 nm. This is the wavelength at which the optical output power is greatest.
• Spectral Line Half-Width (Δλ): 20 nm. This indicates the spectral purity; a narrower width means a more monochromatic color.
• Dominant Wavelength (λ_d): 639 nm. This is the single wavelength perceived by the human eye to match the color of the LED's output.
• Forward Voltage per Chip (V_F): 2.10V (min) to 2.60V (typ) at I_F=20mA. Designers must ensure the driving circuit can accommodate this range.
• Reverse Current per Segment (I_R): Maximum 100 μA at V_R=5V. This parameter is for test purposes only; continuous reverse bias operation is prohibited.
• Luminous Intensity Matching Ratio: 2:1 maximum. This specifies the allowable variation in brightness between segments within a single device to ensure uniform appearance.
• Cross Talk: Specified as < 2.5%. This refers to unwanted illumination of a segment when an adjacent segment is driven, caused by internal optical or electrical leakage.

3. Binning System Explanation

The datasheet indicates the device is \"Categorized for Luminous Intensity.\" This implies a binning process where manufactured LEDs are sorted based on measured light output (typically at a standard test current like 1mA or 10mA) into specific intensity ranges or \"bins.\" This ensures consistency in brightness for a given purchase order. While the specific bin codes are not detailed in this excerpt, designers should consult the manufacturer for available bins to guarantee the required brightness level for their application. The tight 2:1 intensity matching ratio further ensures visual uniformity within a single digit.

4. Performance Curve Analysis

The datasheet references \"Typical Electrical / Optical Characteristics Curves.\" These graphical representations are crucial for understanding device behavior beyond single-point specifications.

• I-V (Current-Voltage) Curve: Would show the relationship between forward current (I_F) and forward voltage (V_F). It demonstrates the diode's exponential characteristic and helps in designing appropriate current-limiting circuitry.
• Luminous Intensity vs. Forward Current (I_V vs. I_F): Shows how light output increases with drive current. It is typically linear over a range but will saturate at very high currents due to thermal effects.
• Luminous Intensity vs. Ambient Temperature (I_V vs. T_a): Illustrates the decrease in light output as junction temperature rises. This is critical for applications operating in high-temperature environments.
• Spectral Distribution: A plot of relative optical power versus wavelength, centering around the 650nm peak with the defined 20nm half-width.

5. Mechanical & Package Information

5.1 Package Dimensions

The display's physical outline and lead positions are defined in a dimensional drawing. Key notes include: all dimensions are in millimeters with a standard tolerance of ±0.25mm unless specified otherwise. Specific quality controls are noted: foreign material or bubbles within a segment must be ≤10 mils, bending of the reflector ≤1% of its length, and surface ink contamination ≤20 mils. The pin tip shift tolerance is ±0.40 mm. For PCB design, a hole diameter of 1.0 mm is recommended for the leads.

5.2 Pin Connection and Polarity

The device has a 10-pin single-row configuration. It is a common cathode type, meaning the cathodes (negative terminals) of all LED segments are connected together internally. There are two common cathode pins (Pin 3 and Pin 8), which are internally connected. This allows for flexibility in PCB layout and heat dissipation. The pinout is as follows: Pin 1: Anode E, Pin 2: Anode D, Pin 3: Common Cathode, Pin 4: Anode C, Pin 5: Anode D.P. (Decimal Point), Pin 6: Anode B, Pin 7: Anode A, Pin 8: Common Cathode, Pin 9: Anode F, Pin 10: Anode G. An internal circuit diagram visually represents these connections.

6. Soldering and Assembly Guidelines

6.1 Automated Soldering

For wave or reflow soldering, the recommended condition is to immerse the leads to a depth of 1/16 inch (approximately 1.6mm) below the seating plane for a maximum of 5 seconds at a peak temperature of 260°C. The critical factor is that the body temperature of the LED display itself must not exceed its maximum rated temperature during this process.

6.2 Manual Soldering

When using a soldering iron, the tip should be applied to the lead at a point 1/16 inch below the seating plane. The soldering time must not exceed 5 seconds, with an iron tip temperature of 350°C ±30°C. Care must be taken to avoid excessive heat transfer to the plastic body of the display.

7. Application Recommendations

7.1 Typical Application Scenarios

• Industrial Control Panels: For displaying setpoints, process values, or error codes.
• Test and Measurement Equipment: Digital multimeters, frequency counters, power supplies.
• Consumer Appliances: Microwave ovens, washing machines, audio equipment.
• Automotive Aftermarket Displays: Gauges and readouts (subject to appropriate qualification).
• Medical Devices: Simple parameter readouts where high reliability is not critical to life support (see Cautions).

7.2 Critical Design Considerations

• Drive Method: Constant current driving is strongly recommended. This ensures consistent luminous intensity regardless of variations in forward voltage (V_F) from device to device or with temperature changes. A simple series resistor with a voltage source can be used if the supply voltage is significantly higher and stable enough to make current variations acceptable.
• Current Limiting: The circuit must be designed to never exceed the absolute maximum continuous current, factoring in the necessary derating for elevated ambient temperatures. The safe operating current should be chosen based on the required brightness and the maximum expected ambient temperature.
• Voltage Compatibility: The driver circuit must be capable of supplying the necessary voltage to achieve the desired current across the entire V_F range (2.10V to 2.60V per segment at 20mA).
• Reverse Voltage Protection: The driving circuit should incorporate protection (e.g., diodes in parallel with the display) to prevent the application of reverse bias or voltage transients during power-up or shutdown, which can damage the LED chips.
• Thermal Management: While the device has a wide operating temperature range, operating at high currents in high ambient temperatures will accelerate light output degradation (lumen depreciation) and may lead to premature failure. Adequate ventilation should be considered.

8. Reliability and Testing

The device undergoes a suite of reliability tests based on recognized military (MIL-STD), Japanese (JIS), and internal standards. These tests validate its robustness and longevity under various environmental stresses.

• Operation Life Test (RTOL): Devices are operated at maximum ratings for 1000 hours to assess long-term performance and failure rates.
• Environmental Stress Tests: Includes High Temperature/Humidity Storage (65°C/90-95% RH for 500Hrs), High Temperature Storage (105°C for 1000Hrs), Low Temperature Storage (-35°C for 1000Hrs), Temperature Cycling, and Thermal Shock. These tests verify the package's integrity and the device's ability to withstand storage and operational environments.
• Solderability Tests: Solder Resistance (260°C for 10s) and Solderability (245°C for 5s) ensure the leads can withstand assembly processes.

9. Technical Comparison and Differentiation

The LTS-6780JD's primary differentiators are its use of AlInGaP technology and hyper red emission. Compared to older GaAsP or GaP LED technologies, AlInGaP offers significantly higher luminous efficiency, resulting in greater brightness for the same drive current or lower power consumption for the same brightness. The hyper red color (650nm peak) is distinct from standard red LEDs (typically around 625-635nm), offering a deeper red hue. The 0.56-inch digit size positions it between smaller (0.3\\