LTD-6410JG LED Display Datasheet - 0.56-inch Digit Height - AlInGaP Green - 2.6V Forward Voltage - 70mW Power Dissipation - English Technical Documentation

1. Product Overview

The LTD-6410JG is a dual-digit, seven-segment LED display module designed for numeric readout applications. It features a digit height of 0.56 inches (14.22 mm), providing clear and legible characters suitable for a variety of electronic equipment. The display utilizes AlInGaP (Aluminum Indium Gallium Phosphide) LED chips grown on a GaAs substrate, which are known for their high efficiency and brightness in the green spectrum. The device has a gray face with white segments, offering high contrast for improved readability. It is categorized for luminous intensity and is offered in a lead-free package compliant with RoHS directives.

1.1 Key Features

• 0.56 inch (14.22 mm) digit height.
• Continuous uniform segments for consistent appearance.
• Low power requirement.
• Excellent character appearance.
• High brightness and high contrast.
• Wide viewing angle.
• Solid-state reliability.
• Categorized for luminous intensity.
• Lead-free package (RoHS compliant).

1.2 Device Identification

The part number LTD-6410JG specifies a dual-digit, common anode, seven-segment display with AlInGaP green LEDs and a right-hand decimal point.

2. Mechanical and Package Information

The display is housed in a standard dual-digit LED package. Critical dimensions and tolerances are provided in the package drawing. Key mechanical notes include:

• All dimensions are in millimeters. General tolerances are ±0.20 mm unless otherwise specified.
• Pin tip shift tolerance is ±0.4 mm.
• Limits are defined for foreign material on segments (≤10 mils), ink contamination on the surface (≤20 mils), bending of the reflector (≤1% of length), and bubbles within segments (≤10 mils).
• A printed circuit board hole diameter of 1.30 mm is recommended for best fit.

The module is marked with the part number (LTD-6410JG), a date code in YYWW format, the manufacturing country, and a bin code for luminous intensity categorization.

3. Electrical Configuration and Pinout

3.1 Internal Circuit Diagram

The display has a common anode configuration. Each of the two digits shares a common anode pin, while each segment (A-G and DP) has individual cathode pins for each digit. This configuration allows for multiplexed driving to control both digits independently.

3.2 Pin Connection Table

The 18-pin device has the following pin assignments:

• Pin 1: Cathode E (Digit 1)
• Pin 2: Cathode D (Digit 1)
• Pin 3: Cathode C (Digit 1)
• Pin 4: Cathode D.P. (Digit 1)
• Pin 5: Cathode E (Digit 2)
• Pin 6: Cathode D (Digit 2)
• Pin 7: Cathode G (Digit 2)
• Pin 8: Cathode C (Digit 2)
• Pin 9: Cathode D.P. (Digit 2)
• Pin 10: Cathode B (Digit 2)
• Pin 11: Cathode A (Digit 2)
• Pin 12: Cathode F (Digit 2)
• Pin 13: Common Anode (Digit 2)
• Pin 14: Common Anode (Digit 1)
• Pin 15: Cathode B (Digit 1)
• Pin 16: Cathode A (Digit 1)
• Pin 17: Cathode G (Digit 1)
• Pin 18: Cathode F (Digit 1)

4. Ratings and Characteristics

4.1 Absolute Maximum Ratings (Ta=25°C)

• Power Dissipation Per Chip: 70 mW
• Peak Forward Current Per Chip (1 kHz, 25% duty cycle): 60 mA
• Continuous Forward Current Per Chip: 25 mA (Derating: 0.33 mA/°C above 25°C)
• Operating Temperature Range: -35°C to +105°C
• Storage Temperature Range: -35°C to +105°C
• Solder Conditions: 1/16 inch below seating plane for 5 seconds at 260°C.

4.2 Electrical and Optical Characteristics (Ta=25°C)

• Average Luminous Intensity (I_V): 320 (Min), 750 (Typ) μcd @ I_F=1 mA
• Peak Emission Wavelength (λ_p): 571 nm (Typ) @ I_F=20 mA
• Spectral Line Half-Width (Δλ): 15 nm (Typ) @ I_F=20 mA
• Dominant Wavelength (λ_d): 572 nm (Typ) @ I_F=20 mA
• Forward Voltage Per Chip (V_F): 2.05 (Min), 2.6 (Max) V @ I_F=20 mA
• Reverse Current Per Chip (I_R): 100 μA (Max) @ V_R=5V
• Luminous Intensity Matching Ratio (Similar Light Area): 2:1 (Max) @ I_F=1 mA
• Cross Talk: ≤2.5%

Notes: Luminous intensity is measured with a CIE eye-response filter. Reverse voltage is for test purposes only and not for continuous operation.

5. Typical Performance Curves

The datasheet includes typical curves illustrating the relationship between forward current and luminous intensity, as well as the variation of forward voltage with temperature. These curves are essential for designers to optimize drive current for desired brightness while managing power dissipation and thermal effects. The high-efficiency AlInGaP technology typically shows a relatively linear relationship between current and light output within the specified operating range.

6. Reliability and Environmental Testing

The LTD-6410JG undergoes a comprehensive suite of reliability tests based on military (MIL-STD) and Japanese industrial (JIS) standards to ensure long-term performance and durability.

• Operation Life Test (RTOL): 1000 hours at maximum rated current under room temperature.
• High Temperature / High Humidity Storage (THS): 500 hours at 65°C ±5°C and 90-95% RH.
• High Temperature Storage (HTS): 1000 hours at 105°C ±5°C.
• Low Temperature Storage (LTS): 1000 hours at -35°C ±5°C.
• Temperature Cycling (TC): 30 cycles between -35°C and 105°C.
• Thermal Shock (TS): 30 cycles of liquid-to-liquid transfer between -35°C and 105°C.
• Solder Resistance (SR): 10 seconds immersion at 260°C.
• Solderability (SA): 5 seconds immersion at 245°C.

7. Soldering and Assembly Guidelines

7.1 Automated Soldering

For wave or reflow soldering, the recommended condition is to keep the solder joint temperature at 260°C for a maximum of 5 seconds, measured 1/16 inch (approximately 1.6 mm) below the seating plane of the display on the PCB.

7.2 Manual Soldering

When using a soldering iron, the tip temperature should be 350°C ±30°C. The soldering time per pin should not exceed 5 seconds, again measured from 1/16 inch below the seating plane.

8. Application Notes and Cautions

8.1 Intended Use and Limitations

This display is designed for ordinary electronic equipment in office, communication, and household applications. It is not recommended for safety-critical systems (aviation, medical life-support, etc.) without prior consultation and qualification.

8.2 Design Considerations

• Absolute Maximum Ratings: The driving circuit must be designed to ensure that the absolute maximum ratings for current, power, and temperature are never exceeded. Operation beyond these limits can cause severe light degradation or catastrophic failure.
• Current Driving: A constant current drive is strongly recommended over a constant voltage drive to ensure stable luminous output and longevity. The current should be set according to the desired brightness, typically between 1 mA and 20 mA per segment.
• Reverse Voltage Protection: The driving circuit must incorporate protection against reverse voltages and transient voltage spikes that may occur during power-up or shutdown sequences. Even brief exposure to reverse bias can damage the LED chips.
• Thermal Management: Although the device can operate up to 105°C, lower junction temperatures prolong lifespan and maintain brightness. Adequate PCB layout and, if necessary, heat sinking should be considered for high ambient temperature applications or when driving at higher currents.
• Multiplexing: Due to its common anode, pin-by-pin configuration, the display is ideal for multiplexed driving. Designers must ensure the multiplexing frequency is high enough to avoid visible flicker (typically >60 Hz) and that the peak current in each multiplexing cycle does not exceed the absolute maximum ratings.

9. Technical Comparison and Advantages

The use of AlInGaP technology provides several key advantages over older technologies like standard GaP or GaAsP LEDs:

• Higher Brightness and Efficiency: AlInGaP LEDs offer significantly higher luminous intensity for the same drive current, enabling lower power consumption or brighter displays.
• Superior Color Purity: The spectral characteristics (peak at 571 nm, narrow half-width) result in a saturated, pure green color that is visually distinct and offers high contrast against the gray background.
• Better Temperature Stability: AlInGaP LEDs generally exhibit less variation in forward voltage and luminous output with temperature changes compared to some other LED types, leading to more consistent performance.
• Categorized Binning: The provision of luminous intensity bin codes allows designers to select displays with matched brightness levels, ensuring uniform appearance in multi-digit or multi-unit applications.

10. Typical Application Scenarios

The LTD-6410JG is well-suited for a wide range of numeric display applications, including:

• Test and measurement equipment (multimeters, frequency counters).
• Industrial control panels and timers.
• Consumer appliances (microwaves, ovens, washing machines).
• Audio/video equipment (amplifiers, tuners).
• Point-of-sale terminals and calculators.
• Automotive aftermarket displays (where environmental specs are met).

11. Frequently Asked Questions (FAQ)

Q: What is the difference between common anode and common cathode?
A: In a common anode display, all the anodes of the LEDs in a digit are connected together to a positive supply. Segments are turned ON by applying a ground (low) signal to their respective cathode pins. The LTD-6410JG is a common anode device.

Q: How do I calculate the required current-limiting resistor?
A: Use Ohm's Law: R = (V_supply - V_F) / I_F. For example, with a 5V supply, a typical V_F of 2.3V per segment, and a desired I_F of 10 mA: R = (5 - 2.3) / 0.01 = 270 Ω. Use the maximum V_F from the datasheet for a conservative design.

Q: Can I drive this display directly from a microcontroller?
A> Most microcontroller GPIO pins cannot source or sink enough current (typically 20-25 mA max, often less). You will need driver transistors (for the common anodes) and likely segment driver ICs (like a 74HC595 shift register with higher current capability or a dedicated LED driver) to interface safely and effectively.

Q: What does "luminous intensity matching ratio 2:1" mean?
A> It means that within a single display unit, the brightness of any segment will not be less than half the brightness of the brightest segment when measured under the same conditions. This ensures visual uniformity.

12. Design and Usage Case Study

Scenario: Designing a simple two-digit counter.
A designer needs a display for a basic event counter that increments from 00 to 99. They choose the LTD-6410JG for its clear readability and standard interface.

1. Circuit Design: They use a small microcontroller to manage the count logic. The microcontroller's I/O pins are connected to the segment cathodes via current-limiting resistors (calculated as above). The two common anode pins are connected to the microcontroller via NPN transistors to handle the higher cumulative current of a fully lit digit (e.g., digit "8" plus decimal point).
2. Software: The firmware implements multiplexing. It turns on the transistor for Digit 1, sets the cathode pins to display the value for the tens place, waits a short interval (e.g., 5 ms), then turns off Digit 1. It then turns on the transistor for Digit 2, sets the cathode pins for the ones place, waits, and turns it off. This cycle repeats rapidly.
3. Result: The display shows a stable, flicker-free two-digit number. The high contrast and brightness of the AlInGaP LEDs make the numbers easily readable even in moderately lit environments. The categorized binning ensures both digits appear equally bright.

13. Operating Principle

An LED (Light Emitting Diode) is a semiconductor device that emits light when current flows through it in the forward direction. In the LTD-6410JG, the light-emitting material is AlInGaP. When a forward voltage exceeding the diode's threshold (approximately 2V) is applied, electrons and holes recombine in the active region of the semiconductor, releasing energy in the form of photons. The specific composition of the AlInGaP alloy determines the wavelength (color) of the emitted light, which in this case is in the green region of the spectrum (~571 nm). The seven segments are individual LEDs arranged in a figure-eight pattern. By selectively illuminating different combinations of these segments, the numerals 0-9 and some letters can be formed.

14. Technology Trends

While discrete seven-segment LED displays like the LTD-6410JG remain highly relevant for their simplicity, reliability, and cost-effectiveness in dedicated numeric applications, broader display technology trends are evident. There is a general shift towards higher integration, such as displays with built-in controllers (I2C or SPI interface) that reduce the microcontroller pin count and software burden. Furthermore, in applications requiring alphanumeric or graphical content, dot-matrix LED displays, OLEDs, and LCDs are increasingly common due to their flexibility. However, for pure numeric output where high brightness, wide viewing angles, and long lifespan are paramount, especially in industrial or outdoor settings, traditional seven-segment LED displays utilizing efficient semiconductor materials like AlInGaP continue to be an excellent and robust choice.