0.56-inch Single Digit 7-Segment LED Display Datasheet - Size 14.22mm Digit Height - Green AlInGaP - 2.6V Forward Voltage - 70mW Power Dissipation - English Technical Document

1. Product Overview

The device is a single-digit, seven-segment alphanumeric display designed for applications requiring clear, bright numeric readouts. Its primary function is to visually represent the digits 0-9 and some letters using individually controllable segments. The core technology is based on Aluminum Indium Gallium Phosphide (AlInGaP) semiconductor material, which is specifically engineered for high-efficiency light emission in the green-yellow spectrum. This material system is grown on a non-transparent Gallium Arsenide (GaAs) substrate, which helps in managing light output and contrast. The display features a gray-colored faceplate which serves to enhance the contrast ratio between the illuminated green segments and the background, improving readability under various lighting conditions. The device is categorized by its luminous intensity, ensuring consistency in brightness levels for applications where uniform appearance across multiple units is critical.

2. In-Depth Technical Parameter Analysis

This section provides a detailed breakdown of the device's operational limits and performance characteristics under specified conditions.

2.1 Absolute Maximum Ratings

These parameters define the stress limits beyond which permanent damage to the device may occur. Operation at or near these limits is not recommended for reliable, long-term performance.

• Power Dissipation per Segment: 70 mW. This is the maximum amount of power that can be safely converted into heat and light by a single segment without risking thermal damage.
• Peak Forward Current per Segment: 60 mA. This rating applies under pulsed conditions (1/10 duty cycle, 0.1ms pulse width). It allows for brief periods of higher current to achieve very high brightness for multiplexing or strobing applications.
• Continuous Forward Current per Segment: 25 mA at 25°C. This current must be derated linearly at a rate of 0.33 mA/°C as the ambient temperature (Ta) rises above 25°C to prevent overheating.
• Reverse Voltage per Segment: 5 V. Exceeding this voltage in the reverse bias direction can cause junction breakdown.
• Operating & Storage Temperature Range: -35°C to +85°C. The device is rated for industrial-grade temperature environments.
• Solder Temperature: The device can withstand a soldering temperature of 260°C for 3 seconds at a distance of 1/16 inch (approximately 1.59 mm) below the seating plane.

2.2 Electrical & Optical Characteristics (Ta=25°C)

These are the typical performance parameters measured under standard test conditions, providing the expected behavior of the device in normal operation.

• Average Luminous Intensity (I_V): 320 μcd (Min), 900 μcd (Typ) at I_F=1mA. This quantifies the perceived brightness of the segment. The wide range indicates a binning process for intensity.
• Peak Emission Wavelength (λ_p): 571 nm (Typ) at I_F=20mA. This is the wavelength at which the optical power output is maximum, placing the emission in the green-yellow region of the visible spectrum.
• Spectral Line Half-Width (Δλ): 15 nm (Typ) at I_F=20mA. This parameter describes the spectral purity of the emitted light; a narrower half-width indicates a more monochromatic color.
• Dominant Wavelength (λ_d): 572 nm (Typ) at I_F=20mA. This is the single wavelength perceived by the human eye that best matches the color of the emitted light, closely related to the peak wavelength.
• Forward Voltage per Segment (V_F): 2.05V (Min), 2.6V (Typ) at I_F=20mA. This is the voltage drop across the LED segment when conducting the specified current. It is crucial for designing the current-limiting circuitry.
• Reverse Current per Segment (I_R): 100 μA (Max) at V_R=5V. This is the small leakage current that flows when the segment is reverse-biased.
• Luminous Intensity Matching Ratio (I_V-m): 2:1 (Typ) at I_F=1mA. This ratio defines the maximum allowable brightness variation between different segments of the same digit or between different devices, ensuring visual uniformity.

Note on Measurement: Luminous intensity is measured using a sensor and filter combination that approximates the CIE photopic luminosity function, which models the standard human eye's sensitivity to different wavelengths.

3. Binning System Explanation

The datasheet indicates the device is "Categorized for Luminous Intensity." This implies a binning or sorting process based on measured light output.

• Luminous Intensity Binning: The specified typical luminous intensity of 900 μcd with a minimum of 320 μcd suggests that devices are tested and grouped (binned) according to their actual measured brightness at the standard test current of 1mA. This allows designers to select parts with consistent brightness levels for their application, which is vital for multi-digit displays where uneven brightness would be distracting.
• Wavelength Consistency: While not explicitly stated as a binned parameter, the tight typical values for Peak Emission Wavelength (571 nm) and Dominant Wavelength (572 nm) indicate a manufacturing process that yields highly consistent color output, which is a characteristic advantage of the AlInGaP material system.

4. Performance Curve Analysis

The datasheet references "Typical Electrical / Optical Characteristic Curves." While the specific graphs are not detailed in the provided text, standard curves for such devices typically include:

• Forward Current vs. Forward Voltage (I_F-V_F Curve): This non-linear curve shows how the forward voltage changes with increasing current. It is essential for determining the required drive voltage and for designing constant-current drivers.
• Luminous Intensity vs. Forward Current (I_V-I_F Curve): This graph shows the relationship between drive current and light output. It is generally sub-linear; doubling the current does not double the brightness and increases heat generation.
• Luminous Intensity vs. Ambient Temperature: This curve demonstrates how light output decreases as the junction temperature of the LED increases. Understanding this derating is critical for applications operating at high ambient temperatures.
• Spectral Distribution: A plot showing the relative optical power across different wavelengths, centered around the peak wavelength of ~571 nm, with a typical half-width of 15 nm.

5. Mechanical & Package Information

5.1 Package Dimensions

The device has a digit height of 0.56 inches (14.22 mm). The package dimensions are provided in a drawing with all measurements in millimeters. The standard tolerance for dimensions is ±0.25 mm (±0.01 inches) unless otherwise specified on the drawing. This information is critical for PCB footprint design and ensuring proper fit within the end product's enclosure.

5.2 Pin Connection & Circuit Diagram

The display has a 10-pin configuration with a common cathode design. The internal circuit diagram shows that all cathodes of the LED segments (A through G and the Decimal Point) are connected internally to two common cathode pins (Pin 3 and Pin 8). This is a standard configuration for simplifying drive circuitry in multiplexed applications.

Pinout:

1. Anode for Segment E
2. Anode for Segment D
3. Common Cathode
4. Anode for Segment C
5. Anode for Decimal Point (D.P.)
6. Anode for Segment B
7. Anode for Segment A
8. Common Cathode
9. Anode for Segment F
10. Anode for Segment G

The dual common cathode pins (3 & 8) are typically connected together on the PCB to provide a better current path and thermal dissipation.

6. Soldering & Assembly Guidelines

The absolute maximum ratings specify a key soldering parameter: the device can withstand a soldering iron or reflow profile that reaches 260°C at a point 1/16 inch (1.59 mm) below the seating plane of the package for a maximum duration of 3 seconds. This guideline is intended to prevent thermal damage to the LED chips and the internal wire bonds during the assembly process. For wave soldering, the exposure time to solder should be minimized. Standard ESD (Electrostatic Discharge) precautions should be observed during handling and assembly to prevent damage to the semiconductor junctions.

7. Application Recommendations

7.1 Typical Application Scenarios

This display is suited for a wide range of applications requiring a single, highly visible numeric indicator:

• Test and Measurement Equipment: Digital multimeters, frequency counters, power supplies, where a clear, bright readout is needed.
• Industrial Controls: Panel meters, process indicators, timer displays on machinery.
• Consumer Electronics: Standalone counters, scoreboards, appliance displays (e.g., microwave ovens, older stereo equipment).
• Automotive Aftermarket: Gauges and diagnostic tools (though environmental specs should be verified for specific automotive requirements).

7.2 Design Considerations

• Current Limiting: LEDs are current-driven devices. A series current-limiting resistor or a constant-current driver circuit is mandatory for each segment anode to prevent exceeding the maximum continuous forward current (25 mA at 25°C). The resistor value can be calculated using Ohm's Law: R = (V_supply - V_F) / I_F, where V_F is the typical forward voltage (e.g., 2.6V).
• Multiplexing: For multi-digit displays, a multiplexing scheme is used where digits are illuminated one at a time rapidly. The peak forward current rating (60 mA) allows for higher pulsed currents to compensate for the reduced duty cycle, maintaining perceived brightness.
• Heat Management: While power dissipation is low per segment, in applications where all segments are lit continuously (e.g., displaying '8.'), the total power can approach 0.5W. Ensure adequate ventilation or heatsinking if operating at high ambient temperatures, and remember to derate the continuous current.
• Viewing Angle: The datasheet claims a "wide viewing angle," which is typical for LED seven-segment displays. This should be verified for the specific application's required viewing cone.

8. Technical Comparison & Differentiation

The key differentiating factors of this display, based on the provided data, are its material technology and specific performance characteristics.

• AlInGaP vs. Traditional Materials: Compared to older technologies like standard GaP (Gallium Phosphide) green LEDs, AlInGaP offers significantly higher luminous efficiency and brightness. This results in better visibility in high-ambient-light conditions or at lower drive currents, improving power efficiency.
• Color and Contrast: The combination of green AlInGaP segments and a gray face provides a high-contrast, easily readable display. Green is often chosen for its high luminous efficacy as perceived by the human eye, making it appear very bright for a given electrical input.
• Solid-State Reliability: Like all LEDs, it offers advantages over incandescent or vacuum fluorescent displays (VFDs), including shock/vibration resistance, faster response time, lower operating voltage, and longer lifetime.

9. Frequently Asked Questions (Based on Technical Parameters)

1. Q: What is the purpose of the two common cathode pins (3 and 8)?
   A: They are internally connected. Providing two pins helps distribute the total cathode current (which can be the sum of up to 8 segments), reduces current density in the PCB traces, and can improve thermal dissipation from the package.
2. Q: Can I drive this display directly from a 5V microcontroller pin?
   A: No. You must use a current-limiting resistor. For a 5V supply and a target current of 20 mA with a V_F of 2.6V, the resistor value would be R = (5V - 2.6V) / 0.02A = 120 Ω. The microcontroller pin must also be able to sink or source the required segment current.
3. Q: What does "Luminous Intensity Matching Ratio of 2:1" mean?
   A: It means that the brightest segment (or device) will be no more than twice as bright as the dimmest segment (or device) under the same test conditions. This ensures visual uniformity across the display.
4. Q: How do I achieve the typical brightness of 900 μcd?
   A> The typical luminous intensity is specified at a forward current (I_F) of 1 mA. To achieve this brightness level in your design, you should drive each segment with 1 mA. For higher brightness, you can increase the current up to the maximum continuous rating (25 mA at 25°C), but refer to the I_V-I_F curve as the relationship is not linear.

10. Design and Usage Case Study

Scenario: Designing a Simple Digital Voltmeter Readout
A designer is creating a 0-99V DC voltmeter. They need two of these displays. The microcontroller's ADC reads the voltage and converts it to two digits. The designer uses a multiplexing technique: Digit 1 (tens place) is illuminated for 5ms, then Digit 2 (ones place) for 5ms, repeating continuously. To maintain good perceived brightness during the 50% duty cycle per digit, they decide to drive each segment with a pulsed current of 15 mA (well below the 60 mA peak rating). They use a transistor on the common cathode side for each digit, controlled by the microcontroller, and current-limiting resistors on each segment anode connected to microcontroller port pins configured as outputs. The gray face and green segments ensure the reading is clear even in a moderately lit workshop environment. The designer selects parts from the same luminous intensity bin to guarantee both digits have matching brightness.

11. Operational Principle

A seven-segment display is an assembly of seven light-emitting diodes (LEDs) arranged in a figure-eight pattern. Each LED forms one segment (labeled A through G). An additional LED is used for the decimal point (DP). By selectively applying forward bias (turning on) specific combinations of these segments, the patterns for numerals 0 through 9 can be formed. For example, to display a "7," segments A, B, and C are illuminated. In a common cathode configuration like this one, all the cathodes (negative terminals) of the segment LEDs are connected together to one or more common pins. To light a segment, its corresponding anode pin is driven to a positive voltage (through a current-limiting resistor), while the common cathode is connected to ground. The AlInGaP semiconductor material emits light when electrons recombine with holes across the device's p-n junction, releasing energy in the form of photons with a wavelength characteristic of the material's bandgap, in this case, green light.

12. Technology Trends

While discrete seven-segment LED displays remain relevant for specific applications, broader trends in display technology are noteworthy. There is a general shift towards integrated dot-matrix displays (both LED and LCD/OLED) that offer full alphanumeric and graphic capabilities in similarly sized packages. These provide greater flexibility but often require more complex drive electronics. For applications where only numbers are needed, the seven-segment format remains highly efficient and cost-effective. Advancements in LED materials, like the use of AlInGaP in this datasheet, continue to improve efficiency, brightness, and color purity. Furthermore, surface-mount device (SMD) versions of seven-segment displays are becoming more common, allowing for automated assembly and smaller form factors compared to through-hole designs like the one likely described in this document. The core advantages of LEDs—long life, robustness, and low power—ensure they will remain a staple in indicator and simple readout applications for the foreseeable future.