LSHD-F101 0.39-inch Single Digit Red LED Display Datasheet - Digit Height 10.0mm - Forward Voltage 2.6V - Power 70mW - English Technical Document

1. Product Overview

The LSHD-F101 is a single-digit, seven-segment plus decimal point LED display module. It utilizes advanced Aluminium Indium Gallium Phosphide (AlInGaP) epitaxial layers grown on a Gallium Arsenide (GaAs) substrate to produce high-efficiency red light emission. The primary application for this device is in electronic equipment where clear, bright, and reliable numeric readouts are required, such as in instrumentation panels, consumer appliances, and industrial controls. Its core advantages include excellent character appearance due to continuous uniform segments, high brightness and contrast for superior visibility, and solid-state reliability ensuring long operational life.

1.1 Key Features

• Digit Height: 0.39 inches (10.0 mm).
• Continuous Uniform Segments for smooth character appearance.
• Low Power Requirement, enhancing energy efficiency.
• High Brightness & High Contrast for excellent readability.
• Wide Viewing Angle, suitable for various mounting positions.
• Solid-State Reliability with no moving parts.
• Categorized for Luminous Intensity, allowing for brightness matching in multi-digit applications.
• Lead-Free Package compliant with RoHS (Restriction of Hazardous Substances) directives.

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. Operation at or near these limits is not recommended for reliable performance.

• Power Dissipation per Segment: 70 mW. This is the maximum power that can be safely dissipated by an individual LED segment without causing thermal damage.
• Peak Forward Current per Segment: 90 mA. This rating applies under pulsed conditions (1/10 duty cycle, 0.1ms pulse width) and is higher than the continuous current rating.
• Continuous Forward Current per Segment: 25 mA at 25°C. This current derates linearly at 0.28 mA/°C as the ambient temperature increases above 25°C. Proper heat sinking or current reduction is necessary at higher temperatures.
• Reverse Voltage per Segment: 5 V. Exceeding this voltage in reverse bias can cause immediate and catastrophic failure.
• Operating and Storage Temperature Range: -35°C to +105°C. The device is rated for operation and storage within this broad industrial temperature range.
• Solder Conditions: The package can withstand soldering at 260°C for a maximum of 5 seconds, measured 1/16 inch (approx. 1.6 mm) below the seating plane.

2.2 Electrical & Optical Characteristics

These are the typical performance parameters measured under specified test conditions (Ta=25°C).

• Average Luminous Intensity per Segment (Iv): Ranges from 200-750 ucd at 1mA drive current to 3400-9750 ucd at 10mA. This high intensity ensures bright display output.
• Peak Emission Wavelength (λp): 650 nm (typical). This specifies the wavelength at which the optical power output is maximum.
• Dominant Wavelength (λd): 639 nm (typical). This is the single wavelength perceived by the human eye, defining the color as red.
• Spectral Line Half-Width (Δλ): 20 nm (typical). This indicates the spectral purity of the emitted red light.
• Forward Voltage per Chip (Vf): 2.10V to 2.60V at a test current of 20mA. Circuit design must accommodate this range to ensure consistent drive current.
• Reverse Current per Segment (Ir): Maximum 100 µA at a reverse voltage of 5V. This parameter is for test purposes only; continuous reverse bias operation is prohibited.
• Luminous Intensity Matching Ratio: Maximum 2:1 between segments when driven at 1mA. This ensures uniform brightness across the display.

3. Binning System Explanation

The datasheet indicates the device is \"Categorized for Luminous Intensity.\" This implies a binning process where displays are sorted based on measured light output at a standard test current (e.g., 1mA or 10mA). This allows designers to select parts from the same or adjacent intensity bins to ensure visual uniformity in multi-digit displays, preventing some digits from appearing brighter or dimmer than others. While specific bin code details are not provided in this excerpt, this categorization is a critical quality control step for aesthetic and functional consistency in the final application.

4. Performance Curve Analysis

The datasheet references \"Typical Electrical / Optical Characteristics Curves\" which are essential for detailed design. These typically include:

• IV Curve (Forward Current vs. Forward Voltage): Shows the exponential relationship, crucial for designing constant-current drivers.
• Luminous Intensity vs. Forward Current: Demonstrates how light output increases with current, aiding in brightness calibration and efficiency calculations.
• Luminous Intensity vs. Ambient Temperature: Shows the derating of light output as temperature rises, important for thermal management.
• Spectral Distribution: A graph plotting relative intensity against wavelength, confirming the dominant and peak wavelengths and spectral width.

Designers should consult these curves to optimize drive conditions, understand temperature dependencies, and predict performance in the actual operating environment.

5. Mechanical & Package Information

5.1 Package Dimensions

The display has a light gray face with white segments. Key dimensional notes include:

• All dimensions are in millimeters with a general tolerance of ±0.25mm unless specified otherwise.
• Pin tip shift tolerance is ±0.40 mm.
• The recommended PCB hole diameter for the pins is 1.0 mm.
• Quality specifications limit foreign materials, bubbles in the segment, bending of the reflector, and surface ink contamination to ensure optical clarity and mechanical integrity.

5.2 Pin Configuration and Circuit Diagram

The device has a 10-pin configuration with a common anode architecture. The internal circuit diagram shows two common anode pins (Pin 1 and Pin 6) connected together internally, providing redundancy and potentially better current distribution. The segment cathodes (A-G and DP) are connected to individual pins. This configuration is standard for multiplexing multiple digits, though this is a single-digit unit. The pinout is as follows: 1-Com Anode, 2-F, 3-G, 4-E, 5-D, 6-Com Anode, 7-DP, 8-C, 9-B, 10-A.

6. Soldering & Assembly Guidelines

6.1 Automated Soldering

Recommended condition: 260°C for 5 seconds, measured 1.6mm (1/16 inch) below the seating plane of the package. The component body temperature must not exceed its maximum rating during this process.

6.2 Manual Soldering

Recommended condition: 350°C ±30°C for a maximum of 5 seconds, with the iron tip positioned 1.6mm below the seating plane. Care must be taken to avoid prolonged heat exposure.

7. Application Recommendations

7.1 Typical Application Scenarios

This display is intended for ordinary electronic equipment including office equipment, communication devices, and household appliances. Its high brightness and readability make it suitable for panel meters, clock displays, simple control unit readouts, and consumer electronics where a clear numeric indicator is needed.

7.2 Critical Design Considerations

• Drive Method: Constant current driving is strongly recommended over constant voltage to ensure consistent luminous intensity and longevity, as LED brightness is a function of current, not voltage.
• Current Limiting: The driver circuit must limit the current to each segment to within the absolute maximum rating (25mA continuous, derated with temperature). Exceeding this causes rapid degradation.
• Voltage Range: The circuit must be designed to accommodate the full forward voltage (Vf) range of 2.10V to 2.60V to deliver the intended current to all units.
• Reverse Voltage Protection: The driving circuit should incorporate protection (e.g., series diodes or integrated circuit features) to prevent reverse voltage or voltage spikes from being applied to the LED cathodes during power-up, shutdown, or in fault conditions.
• Thermal Management: The safe operating current must be derated based on the maximum ambient temperature of the application environment, using the derating factor of 0.28 mA/°C above 25°C.

8. Reliability Testing

The device undergoes a comprehensive suite of reliability tests based on military (MIL-STD), Japanese industrial (JIS), and internal standards. These tests validate its robustness and longevity:

• Operating Life (RTOL): 1000 hours at maximum rated current under room temperature.
• Environmental Stress: Includes High Temperature/Humidity Storage (500hrs at 65°C/90-95% RH), High & Low Temperature Storage (1000hrs at 105°C and -35°C), Temperature Cycling, and Thermal Shock tests.
• Process Robustness: Solder Resistance and Solderability tests ensure the package can withstand standard assembly processes.

9. Cautions and Usage Limitations

The device is not designed for safety-critical applications where failure could jeopardize life or health (e.g., aviation, medical life-support, transportation safety systems). For such applications, consultation with the manufacturer for specially qualified components is mandatory. The manufacturer assumes no liability for damages resulting from operation outside the absolute maximum ratings or contrary to the instructions provided. Special attention is required to avoid reverse bias, which can induce metal migration and lead to increased leakage current or failure.

10. Technical Comparison and Differentiation

The LSHD-F101 differentiates itself through its use of AlInGaP technology on a GaAs substrate. Compared to older technologies like standard GaAsP or GaP, AlInGaP LEDs offer significantly higher luminous efficiency, resulting in greater brightness for the same drive current. The \"continuous uniform segments\" feature indicates a high-quality mold and diffuser design that eliminates visible gaps or hotspots within a segment, leading to a more professional and legible character appearance. The wide viewing angle and categorized luminous intensity are further advantages for applications requiring consistent visual performance from different perspectives or across multiple units.

11. Frequently Asked Questions (Based on Technical Parameters)

Q: Can I drive this display with a 5V supply and a simple resistor?
A: Yes, but careful calculation is needed. Using Ohm's Law (R = (Vsupply - Vf_led) / I_led), and assuming a worst-case Vf of 2.6V at 20mA, the resistor value would be (5V - 2.6V) / 0.02A = 120 Ohms. However, due to Vf variation, brightness may vary between segments/displays. A constant current driver is preferred for consistency.

Q: What is the difference between Peak Wavelength and Dominant Wavelength?
A: Peak Wavelength (650nm) is the physical peak of the emitted light spectrum. Dominant Wavelength (639nm) is the single wavelength that would produce the same color perception to the human eye. Dominant wavelength is more relevant for color specification.

Q: Why are there two Common Anode pins?
A> This provides mechanical symmetry, simplifies PCB layout, and can help distribute current more evenly, potentially improving reliability and brightness uniformity.

12. Design and Usage Case Study

Scenario: Designing a simple digital voltmeter readout.
A designer selects the LSHD-F101 for a 2-digit voltmeter display (requiring two units). They first check the intensity binning information to source two displays from the same bin for uniform brightness. The microcontroller operates at 3.3V. To drive each segment at a target of 10mA for good brightness, they design a constant-current sink driver using a transistor array IC. The driver circuit includes protection diodes to clamp any inductive voltage spikes from the long wires connecting to the display panel. The PCB layout places the displays with adequate spacing for the recommended 1.0mm mounting holes and includes a ground plane for thermal dissipation. During testing, they verify segment brightness at the maximum expected ambient temperature of 50°C and confirm the current is appropriately derated to approximately 18mA per segment (25mA - (0.28mA/°C * (50-25)°C)).

13. Operational Principle Introduction

Light emission in the LSHD-F101 is based on electroluminescence in a semiconductor p-n junction made from AlInGaP materials. When a forward voltage exceeding the junction's built-in potential is applied, electrons from the n-type region and holes from the p-type region are injected into the active region. Here, they recombine, releasing energy in the form of photons. The specific composition of the AlInGaP alloy determines the bandgap energy, which directly corresponds to the wavelength (color) of the emitted light—in this case, red. The GaAs substrate is optically absorbent, so the chip is designed for top-side emission, which is then diffused by the molded plastic package to form the uniform segments.

14. Technology Trends and Context

AlInGaP technology represents a mature and highly efficient solution for red, orange, and yellow LEDs. While newer technologies like Gallium Nitride (GaN) based LEDs dominate the blue, green, and white lighting markets, AlInGaP remains the material of choice for high-performance red indicators and displays due to its superior efficiency and color purity in that spectral region. Trends in display technology include the move towards surface-mount device (SMD) packages for automated assembly and higher density. While the LSHD-F101 is a through-hole component, its design principles of high brightness, reliability, and categorized performance remain fundamental. Future developments may focus on further efficiency gains, wider temperature ranges, and integration with driver electronics.