LSHD-A101 LED Display Datasheet - 0.3-inch Digit Height - AlInGaP Red - 2.6V Forward Voltage - 70mW Power Dissipation - English Technical Document

1. Product Overview

The LSHD-A101 is a single-digit, seven-segment plus decimal point LED display module. It features a digit height of 0.3 inches (7.62 mm), designed for clear numeric readouts in various electronic applications. The device utilizes advanced AS-AlInGaP (Aluminum Indium Gallium Phosphide) red LED chips epitaxially grown on a GaAs substrate. This technology is known for its high efficiency and excellent luminous performance. The display presents a high-contrast appearance with a light gray face and bright white segments, ensuring good readability under different lighting conditions. Its solid-state construction offers inherent reliability advantages over other display technologies.

1.1 Key Features

• Compact Size: 0.3-inch digit height suitable for space-constrained applications.
• Superior Optical Performance: Offers high brightness, high contrast, and a wide viewing angle for excellent character appearance.
• Uniform Illumination: Continuous, uniform segments ensure consistent light output across the digit.
• Low Power Consumption: Designed for efficient operation with low power requirements.
• Enhanced Reliability: Solid-state design provides long operational life and robustness.
• Quality Assurance: Devices are categorized (binned) for luminous intensity to ensure performance consistency.
• Environmental Compliance: The package is lead-free, manufactured in accordance with RoHS directives.

1.2 Device Configuration

The LSHD-A101 is configured as a common anode display. This means the anodes of all LED segments are connected internally and brought out to common pins, while each segment's cathode is individually accessible. This specific model includes a right-hand decimal point (DP). The common anode configuration is often preferred in multiplexed drive circuits for simplified current sinking.

2. Technical Specifications Deep Dive

2.1 Absolute Maximum Ratings

These ratings define the limits beyond which permanent damage to the device may occur. Operation should always be maintained within these boundaries.

• Power Dissipation per Segment: 70 mW maximum.
• Peak Forward Current per Segment: 90 mA (under pulsed conditions: 1/10 duty cycle, 0.1ms pulse width).
• Continuous Forward Current per Segment: 25 mA at 25°C. This rating derates linearly at 0.28 mA/°C as ambient temperature increases above 25°C.
• Operating & Storage Temperature Range: -35°C to +105°C.
• Soldering Condition: The device can withstand wave soldering with the solder bath 1/16 inch (approx. 1.6 mm) below the seating plane for 3 seconds at 260°C. The unit's body temperature must not exceed the maximum temperature rating during assembly.

2.2 Electrical & Optical Characteristics

Typical performance is measured at an ambient temperature (Ta) of 25°C.

• Luminous Intensity (I_V): The light output is categorized. Typical values are 692 µcd at 1 mA drive current and can reach 9000 µcd at 10 mA. The minimum specified is 200 µcd at 1 mA.
• Wavelength Characteristics: The device emits red light. The peak emission wavelength (λ_p) is typically 650 nm. The dominant wavelength (λ_d) is typically 639 nm. The spectral line half-width (Δλ) is 20 nm, indicating the color purity.
• Forward Voltage (V_F): Per LED chip, the voltage drop is typically 2.6V with a maximum of 2.6V when driven at 20 mA. The minimum is 2.1V.
• Reverse Current (I_R): Maximum 100 µA when a reverse voltage (V_R) of 5V is applied. This parameter is for test purposes only; continuous reverse bias operation is prohibited.
• Luminous Intensity Matching Ratio: For segments within a similar light area, the ratio of maximum to minimum intensity will not exceed 2:1 when driven at 1 mA, ensuring uniform brightness.
• Cross Talk: Specified to be ≤ 2.5%, meaning minimal unwanted illumination of non-selected segments.

3. Mechanical & Package Information

3.1 Package Dimensions

The display follows a standard 10-pin dual in-line package (DIP) footprint. Key dimensional notes include:

• All dimensions are in millimeters with a general tolerance of ±0.25 mm unless otherwise specified.
• Pin tip shift tolerance is ±0.4 mm.
• Allowable imperfections: foreign material on a segment ≤10 mils, surface ink contamination ≤20 mils, bubbles in a segment ≤10 mils.
• Reflector bending must be ≤ 1% of its length.
• The recommended PCB hole diameter for the pins is 1.0 mm to ensure a proper fit.

3.2 Pin Connection & Circuit Diagram

The internal circuit is a standard common anode configuration for a 7-segment plus decimal point display. The pinout is as follows:

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

Pin 6 is also a Common Anode, typically connected internally to Pin 1. There is one No Connection (NC) pin in the layout. This pinout allows for straightforward interfacing with microcontrollers or driver ICs.

4. Performance Curve Analysis

While specific graphical curves are referenced in the datasheet, the typical relationships can be described based on the provided parameters:

• Current vs. Luminous Intensity (I-V Curve): The luminous intensity increases super-linearly with forward current. For example, increasing current from 1 mA to 10 mA results in a more than tenfold increase in typical light output (from 692 µcd to 9000 µcd), highlighting the high efficiency of the AlInGaP material.
• Forward Voltage vs. Current: The V_F has a positive temperature coefficient and will vary slightly with current. The specified 2.1V to 2.6V range at 20 mA must be accounted for in the driving circuit design.
• Temperature Dependence: Luminous intensity typically decreases as junction temperature increases. The derating of continuous current (0.28 mA/°C above 25°C) is a direct measure to manage junction temperature and maintain reliability. Operating at higher ambient temperatures requires reducing the drive current accordingly.

5. Application Guidelines & Cautions

5.1 Intended Use & Design Considerations

This display is designed for ordinary electronic equipment in office, communication, and household applications. For safety-critical applications (aviation, medical, etc.), consultation with the manufacturer is mandatory prior to use. Key design and usage cautions include:

• Drive Circuit Design: Constant current driving is strongly recommended to ensure stable brightness and longevity. The circuit must be designed to deliver the intended current across the full V_F range (2.1V-2.6V).
• Protection: The circuit must protect against reverse voltages and voltage transients during power cycling to prevent damage.
• Thermal Management: Exceeding the recommended drive current or operating temperature will accelerate light output degradation and can cause premature failure. The safe operating current must be selected based on the maximum expected ambient temperature.
• Avoid Condensation: Rapid temperature changes in humid environments can cause condensation on the display, which should be avoided.
• Mechanical Handling: Do not apply abnormal force to the display body during assembly. If using a front-application film, avoid having it in direct, pressured contact with the front panel to prevent shifting.
• Consistency in Multi-Digit Arrays: When using two or more displays in one assembly, it is recommended to use devices from the same luminous intensity bin to avoid noticeable brightness or hue differences between digits.

5.2 Storage & Handling Conditions

Proper storage is crucial to maintain solderability and performance.

• Standard Storage (in original packaging): Temperature: 5°C to 30°C. Humidity: Below 60% RH. Prolonged storage outside these conditions can lead to pin oxidation.
• Post-Bag Opening: If the moisture barrier bag is opened, it is advised to consume the products promptly. If the opened product is stored for more than 6 months, a bake-out at 60°C for 48 hours is recommended before use, with assembly completed within one week after baking.
• General Advice: Avoid maintaining large inventories for long periods. Use a first-in, first-out (FIFO) inventory system.

6. Binning System & Ordering Information

The LSHD-A101 is categorized (binned) specifically for luminous intensity. This means units are tested and sorted based on their light output at a standard test current (likely 1 mA or 10 mA). This allows designers to select displays with matched brightness for applications requiring uniformity. The part number LSHD-A101 identifies the specific model: a single-digit, AlInGaP red, common anode display with a right-hand decimal point. Designers should specify any binning requirements when ordering to ensure consistency across production runs.

7. Typical Application Scenarios

The LSHD-A101 is ideal for applications requiring a single, highly readable numeric digit. Common uses include:

• Test and Measurement Equipment: Displaying a single parameter value, such as a mode indicator or a unit digit in a larger display.
• Consumer Appliances: Timers, counters, or status indicators on microwaves, coffee makers, or audio equipment.
• Industrial Controls: Panel meters, process indicators, or setting displays on machinery.
• Automotive Aftermarket: Simple gauges or display modules.
• Prototyping and Educational Kits: Due to its standard DIP package, it is easy to use on breadboards and prototype PCBs.

8. Design Considerations & FAQ

8.1 Current-Limiting Resistor Calculation

For a simple constant-voltage drive (e.g., 5V supply) with a current-limiting resistor, the resistor value (R) can be approximated using Ohm's Law: R = (V_supply - V_F) / I_F. Using the maximum V_F of 2.6V at 20 mA and a 5V supply: R = (5V - 2.6V) / 0.02A = 120 Ω. A standard 120 Ω resistor would be suitable, but the actual current will vary with the specific V_F of the unit. For precision, a constant current driver is preferred.

8.2 Multiplexing Multiple Digits

While the LSHD-A101 is a single digit, the principle applies if using multiple single-digit units. With a common anode design, multiplexing involves sequentially enabling (setting high) the common anode of one digit at a time while applying the appropriate cathode pattern (segments low) for that digit. The persistence of vision creates the illusion of all digits being on simultaneously. This greatly reduces the required microcontroller I/O pins and power consumption.

8.3 Why is Reverse Bias Prohibited?

Applying a reverse voltage (cathode higher than anode) can cause electromigration of metal within the semiconductor chip. This can degrade the LED, leading to increased leakage current or even a short-circuit failure. The driving circuit must ensure this condition does not occur, especially during power-up/down sequences or in multiplexed circuits where voltage spikes are possible.

9. Technology Background & Trends

9.1 AlInGaP Technology

Aluminum Indium Gallium Phosphide (AlInGaP) is a semiconductor material specifically engineered for high-brightness red, orange, and yellow LEDs. Grown on a GaAs substrate, it offers superior luminous efficacy and thermal stability compared to older technologies like GaAsP. This results in the high brightness and excellent reliability noted in the LSHD-A101's features.

9.2 Display Technology Context

While single-digit LED displays like the LSHD-A101 remain relevant for specific, often cost-sensitive or simplicity-driven applications, the broader trend in information display has moved towards integrated dot-matrix LED panels, OLEDs, and LCDs. These offer flexibility in displaying alphanumeric characters and graphics. However, the 7-segment LED display persists due to its unmatched simplicity, extreme readability (especially in high-ambient light), low cost for single or few digits, and proven long-term reliability in harsh environments where other technologies may fail.