LTS-5825SW-P LED Display Datasheet - 0.56-inch Digit Height - White Segments - 3.2V Forward Voltage - English Technical Document

1. Product Overview

The LTS-5825SW-P is a surface-mount device (SMD) designed as a single-digit numeric display. Its primary function is to provide clear, high-visibility numeric readouts in electronic equipment. The core component is an Indium Gallium Nitride (InGaN) white LED chip mounted on a sapphire substrate. This construction is known for its efficiency and stability. The display features a gray faceplate which enhances contrast, combined with white-light emitting segments for the characters.

1.1 Key Features and Advantages

The device offers several distinct advantages for integration into modern electronic designs:

• Digit Size: A 0.56-inch (14.22 mm) digit height provides excellent readability from a distance, making it suitable for panel meters, instrumentation, and consumer appliances.
• Optical Performance: It delivers high brightness and high contrast, ensuring clear visibility even in well-lit environments. The wide viewing angle allows the display to be read from various positions without significant loss of clarity.
• Segment Design: Continuous uniform segments contribute to a clean and professional character appearance, avoiding the \"dot-matrix\" look of some displays.
• Power Efficiency: The InGaN technology enables low power consumption per segment, which is critical for battery-powered or energy-sensitive applications.
• Reliability: As a solid-state device, it offers high reliability and long operational life with no moving parts to wear out.
• Quality Assurance: Devices are categorized (binned) for luminous intensity, allowing designers to select components with consistent brightness levels for uniform display panels.
• Environmental Compliance: The package is lead-free and manufactured in accordance with RoHS (Restriction of Hazardous Substances) directives.

2. Technical Specifications Deep Dive

This section provides a detailed, objective analysis of the device's operational limits and performance characteristics under defined conditions.

2.1 Absolute Maximum Ratings

These ratings define the stress limits beyond which permanent damage to the device may occur. Operation at or beyond these limits is not guaranteed.

• Power Dissipation per Segment: 35 mW maximum. Exceeding this can lead to overheating and accelerated degradation of the LED chip.
• Peak Forward Current per Segment: 50 mA, but only under pulsed conditions (1/10 duty cycle, 0.1 ms pulse width). This rating is for brief, high-current pulses, not continuous operation.
• Continuous Forward Current per Segment: The base rating is 10 mA at 25°C. A derating factor of 0.1 mA/°C applies above 25°C. For example, at 85°C, the maximum continuous current would be: 10 mA - ((85°C - 25°C) * 0.1 mA/°C) = 4 mA.
• Temperature Range: The device is rated for operation from -35°C to +105°C and can be stored within the same range.
• Soldering Conditions: The device can withstand wave or reflow soldering with the iron tip positioned at least 1/16 inch (approx. 1.6 mm) below the seating plane for a maximum of 3 seconds at 260°C.

2.2 Electrical and Optical Characteristics

These are the typical performance parameters measured at Ta=25°C and a forward current (I_F) of 5 mA, which is a common test and operating condition.

• Average Luminous Intensity (I_V): Ranges from a minimum of 71 mcd to a maximum of 165 mcd. The intensity is measured using a sensor filtered to match the photopic (daylight-adapted) response of the human eye (CIE curve).
• Chromaticity Coordinates (x, y): The typical color point is specified at x=0.294, y=0.286 on the CIE 1931 chromaticity diagram. This defines the white color emitted by the segments.
• Forward Voltage per Chip (V_F): Typically between 2.7V and 3.2V at 5 mA. This parameter is important for designing the current-limiting circuitry for the display.
• Reverse Current (I_R): Maximum 100 µA at a reverse voltage (V_R) of 5V. It is critical to note that this is a test condition only; the LED is not designed to operate under reverse bias.
• Luminous Intensity Matching Ratio (I_V-m): A maximum ratio of 2:1 for segments within a similar light area. This ensures that all segments of a digit have reasonably uniform brightness.
• Crosstalk Specification: Defined as ≤ 2.5%. This measures the unintended illumination of an adjacent segment when another is driven, which should be minimal for a clean display.

2.3 Electrostatic Discharge (ESD) Sensitivity

Like most semiconductor devices, the LED chip is susceptible to damage from electrostatic discharge. The datasheet strongly recommends standard ESD prevention practices: using grounded wrist straps or anti-static gloves, ensuring all workstations and equipment are properly grounded, and employing ionizers to neutralize static charges that may accumulate on the plastic package during handling.

3. Binning System Explanation

To ensure consistency in production, devices are sorted into bins based on key parameters. This allows manufacturers to select parts with nearly identical characteristics for a uniform end product.

3.1 Forward Voltage (V_F) Binning

Devices are categorized into bins (3 through 7) based on their forward voltage at 5 mA. Each bin has a 0.1V range (e.g., Bin 3: 2.70V-2.80V, Bin 4: 2.80V-2.90V). The tolerance within each bin is ±0.1V. Matching V_F bins helps in designing simpler, more uniform driver circuits.

3.2 Luminous Intensity (I_V) Binning

This is a critical binning parameter for display uniformity. Bins are labeled (e.g., Q11, Q12, R11, R21) with defined minimum and maximum luminous intensity values in millicandelas (mcd). For instance, bin R21 covers 146.0 to 165.0 mcd. The tolerance for each intensity bin is ±15%. Using parts from the same or adjacent I_V bins is essential for a display where all digits have equal brightness.

3.3 Hue (Color) Binning

The white color point is also binned. The datasheet defines several hue bins (S1-2, S2-2, S3-1, etc.), each specifying a quadrilateral area on the CIE 1931 chromaticity diagram defined by four (x, y) coordinate pairs. The typical point (x=0.294, y=0.286) falls within the S3-1 and S4-1 bins. The tolerance for each hue coordinate is ±0.01. Consistent color bins prevent noticeable color differences between segments or digits in a multi-digit display.

4. Mechanical and Package Information

4.1 Package Dimensions

The device conforms to a standard SMD footprint. All critical dimensions are provided in millimeters with a general tolerance of ±0.25 mm unless otherwise specified. Key dimensional notes include limits on foreign material within the segment area (≤10 mils), surface ink contamination (≤20 mils), allowable bubbles in the segment (≤10 mils), maximum bending of the reflector (≤1% of its length), and a maximum burr size of 0.14 mm on the plastic pins. These ensure mechanical compatibility and visual quality.

4.2 Pin Configuration and Circuit Diagram

The LTS-5825SW-P is a common anode device. The internal circuit diagram shows ten pins controlling the seven main segments (A through G), the decimal point (DP), and two common anode connections. The pinout is as follows: Pin 1: Cathode E, Pin 2: Cathode D, Pin 3: Common Anode, Pin 4: Cathode C, Pin 5: Cathode DP, Pin 6: Cathode B, Pin 7: Cathode A, Pin 8: Common Anode, Pin 9: Cathode F, Pin 10: Cathode G. Pin 3 and Pin 8 are internally connected as the common anode. To illuminate a segment, its corresponding cathode pin must be driven low (connected to ground or a current sink) while the common anode is held high (connected to the positive supply through a current-limiting resistor).

5. Assembly and Application Guidelines

5.1 SMT Soldering Instructions

The device is designed for surface-mount assembly using reflow soldering processes. A critical instruction is that the number of reflow process cycles should be limited to less than two times. Repeated thermal cycling can stress the package and solder joints. The cooling process after reflow should return the assembly to normal ambient temperature in a controlled manner to prevent thermal shock.

5.2 Application Suggestions

The LTS-5825SW-P is ideal for applications requiring a single, highly readable numeric display. Common use cases include:

• Test and Measurement Equipment: Digital multimeters, frequency counters, power supplies.
• Consumer Appliances: Microwave ovens, air conditioners, washing machines (for timer or temperature display).
• Industrial Controls: Panel meters for process monitoring, counter displays.
• Automotive Aftermarket: Gauges and readouts.

5.2.1 Design Considerations

• Current Limiting: Always use a series resistor for each segment or the common anode to limit current to the rated value (e.g., 5-10 mA typical). The resistor value is calculated as R = (V_supply - V_F) / I_F.
• Multiplexing: For multi-digit displays using similar components, time-division multiplexing can be used to control multiple digits with fewer driver pins. Ensure the peak current in multiplexed operation does not exceed the absolute maximum ratings.
• ESD Protection: Incorporate ESD protection diodes on input lines if the display is in a user-accessible area, in addition to handling precautions during assembly.

6. Technical Comparison and Trends

6.1 Principle of Operation

The device operates on the principle of electroluminescence in a semiconductor p-n junction. When a forward voltage exceeding the diode's threshold (V_F) is applied, electrons and holes recombine in the active region of the InGaN chip, releasing energy in the form of photons (light). The sapphire substrate provides a stable, lattice-matched base for growing the high-quality InGaN layers necessary for efficient white light emission, often achieved using a blue LED chip with a phosphor coating.

6.2 Differentiation and Trends

Compared to older technologies like red GaAsP LEDs or vacuum fluorescent displays (VFDs), InGaN-based white LEDs offer superior efficiency, longer lifetime, lower operating voltage, and a more modern appearance. The trend in SMD displays is towards higher pixel density (more segments or dot-matrix), full-color capability (RGB), and integration with touch sensors or microcontrollers. However, for simple, low-cost, high-reliability numeric readouts, single-digit segment displays like the LTS-5825SW-P remain highly relevant due to their simplicity, excellent readability, and proven performance.