LTS-5003AJD LED Display Datasheet - 0.56-inch Digit Height - AlInGaP Red - 2.6V Forward Voltage - English Technical Document

1. Product Overview

The LTS-5003AJD is a single-digit, seven-segment alphanumeric display designed for applications requiring clear, bright numeric readouts. Its primary function is to provide a highly legible visual output for digital data. The core advantage of this device lies in its utilization of advanced Aluminium Indium Gallium Phosphide (AlInGaP) light-emitting diode (LED) chip technology. This material system is known for producing high-efficiency red light, contributing directly to the display's key benefits: high luminous intensity, excellent contrast, and superior character appearance. The device is categorized for luminous intensity, ensuring consistent brightness levels across production batches. Its target market includes industrial control panels, test and measurement equipment, consumer appliances, and any embedded system where a reliable, low-power numeric indicator is required.

2. Technical Parameter Deep Dive

2.1 Photometric and Optical Characteristics

The optical performance is central to the display's functionality. Under a standard test condition of a 10mA forward current (IF), the average luminous intensity (Iv) ranges from a minimum of 320 µcd to a typical maximum of 700 µcd. This high brightness is a direct result of the AlInGaP chip's efficiency. The color characteristics are defined by specific wavelengths: the peak emission wavelength (λp) is typically 656 nanometers (nm), while the dominant wavelength (λd) is 640 nm, placing it firmly in the red region of the visible spectrum. The spectral line half-width (Δλ) is 22 nm, indicating a relatively pure color emission. A critical parameter for multi-segment uniformity is the luminous intensity matching ratio, which is specified at a maximum of 2:1 between segments at IF=10mA, ensuring balanced illumination across the digit.

2.2 Electrical Characteristics

The electrical parameters define the operating boundaries and power requirements. The absolute maximum ratings set hard limits: the continuous forward current per segment is 25 mA, with a derating factor of 0.33 mA/°C above 25°C. The peak forward current, for pulsed operation (1/10 duty cycle, 0.1ms pulse width), can reach 90 mA. The maximum reverse voltage per segment is 5V. Under normal operating conditions (IF=20mA), the forward voltage (VF) per segment typically ranges from 2.1V to 2.6V. The reverse current (IR) is a maximum of 100 µA at VR=5V. The power dissipation per segment must not exceed 70 mW.

2.3 Thermal and Environmental Specifications

The device is rated for an operating temperature range of -35°C to +85°C, with an identical storage temperature range. This wide range makes it suitable for various environmental conditions. The soldering temperature specification is crucial for assembly: the device can withstand 260°C for 3 seconds at a point 1/16 inch (approximately 1.59 mm) below the seating plane, which is a standard reference for wave or reflow soldering processes.

3. Binning System Explanation

The datasheet indicates that the device is \"categorized for luminous intensity.\" This implies a binning system based on measured light output at a fixed current (likely 10mA). While specific bin codes are not detailed in this document, such a system ensures that customers receive displays with consistent and predictable brightness levels. Designers can select bins appropriate for their application's contrast requirements, with higher-intensity bins typically used for high-ambient-light conditions.

4. Performance Curve Analysis

The datasheet references \"Typical Electrical / Optical Characteristic Curves,\" which are essential for detailed design work. Although the specific graphs are not provided in the text, typical curves for such a device would include: Forward Current vs. Forward Voltage (I-V Curve): This shows the nonlinear relationship between current and voltage, crucial for designing current-limiting circuitry. Luminous Intensity vs. Forward Current (I-L Curve): This demonstrates how light output increases with current, helping to optimize the trade-off between brightness and power consumption. Luminous Intensity vs. Ambient Temperature: This curve shows how light output decreases as temperature rises, which is vital for designs operating at high temperatures.

5. Mechanical and Package Information

The device features a standard 10-pin single-digit seven-segment display package. The digit height is 0.56 inches (14.22 mm). The package dimensions drawing (referenced but not detailed in text) would provide critical mechanical data. The device has a gray face with white segments, which enhances contrast by reducing reflected ambient light from the non-illuminated areas. The pin connection is clearly defined: Pins 3 and 8 are the common cathodes, while pins 1, 2, 4, 5, 6, 7, 9, and 10 are the anodes for segments E, D, C, Decimal Point, B, A, F, and G respectively. The internal circuit diagram confirms a common cathode configuration, where all LED segment cathodes are connected together internally.

6. Soldering and Assembly Guidelines

Adherence to the absolute maximum rating for solder temperature is paramount. The specification of 260°C for 3 seconds, measured 1/16 inch below the seating plane, is designed to prevent thermal damage to the LED chips and the epoxy package. For reflow soldering, a profile that stays within this limit must be used. Standard precautions for handling electrostatic discharge (ESD)-sensitive devices should be observed, although not explicitly stated, as LEDs are generally susceptible to ESD. Storage should be within the specified -35°C to +85°C range in a low-humidity environment.

7. Packaging and Ordering Information

The primary ordering code is LTS-5003AJD. The \"Rt. Hand Decimal\" description in the part number table suggests this version includes a right-hand decimal point. Packaging specifics (tube, tray, or reel) and quantities are not detailed in this excerpt. The \"Spec No.: DS30-2001-364\" and \"BNS-OD-FC001/A4\" are internal document control numbers.

8. Application Suggestions

8.1 Typical Application Scenarios

This display is ideal for any device requiring a single numeric digit. Common applications include: digital multimeters, frequency counters, clock displays (for seconds or minutes), industrial timer controls, appliance control panels (e.g., ovens, microwaves), and status indicator panels showing a single parameter like a channel number or error code.

8.2 Design Considerations

Current Limiting: Each segment must be driven with a current-limiting resistor. The resistor value is calculated using the formula R = (Vcc - VF) / IF, where VF is the forward voltage (use max 2.6V for reliability), Vcc is the supply voltage, and IF is the desired forward current (not to exceed 25 mA continuous). Driver Circuitry: As a common-cathode device, it is best driven by a microcontroller or decoder IC that can sink current (pull the common cathode low) and source current to the individual segment anodes. Multiplexing multiple digits is a common technique, but this is a single-digit device. Viewing Angle: The datasheet claims a wide viewing angle, which is beneficial for panels viewed from off-axis positions.

9. Technical Comparison

Compared to older technologies like standard GaAsP or GaP red LEDs, the AlInGaP technology in the LTS-5003AJD offers significantly higher luminous efficiency, resulting in greater brightness for the same drive current. Compared to contemporary alternatives, its key differentiators are the specific 0.56-inch digit height, the high-efficiency red color, and the common cathode configuration. Displays with larger digits, different colors (e.g., green, yellow), or common anode configurations would serve different design needs.

10. Frequently Asked Questions (Based on Technical Parameters)

Q: What is the purpose of the two common cathode pins (3 and 8)?
A: They are internally connected. Having two pins provides better current distribution and mechanical stability, and allows for flexibility in PCB layout.

Q: Can I drive this display directly from a 5V microcontroller pin?
A: No. You must use a current-limiting resistor. For example, with a 5V supply and a target IF of 20mA, and using VF(max)=2.6V, the resistor value would be (5V - 2.6V) / 0.02A = 120 Ohms. Always verify the microcontroller's pin current sourcing capability.

Q: What does \"low power requirement\" mean quantitatively?
A: At a typical operating point of 10mA per segment and VF=2.6V, the power per segment is 26 mW. Illuminating all 7 segments (plus decimal) would draw 80mA total, consuming about 208 mW, which is relatively low for a bright display.

Q: How is the luminous intensity measured?
A: As noted, it is measured with a sensor and filter that approximates the CIE photopic eye-response curve, ensuring the measurement correlates with human brightness perception.

11. Practical Use Case

Consider designing a simple digital tachometer for a motor. A microcontroller measures pulse frequency from a sensor. This frequency value is converted to RPM. The single most significant digit of the RPM (e.g., the \"thousands\" digit) could be displayed using the LTS-5003AJD. The microcontroller would calculate which segments (A-G) to illuminate to form that digit, then drive the common cathode low and set the corresponding anode pins high through current-limiting resistors. The high brightness ensures readability in a workshop environment.

12. 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 turn-on voltage is applied across a segment (anode positive, cathode negative), electrons and holes recombine in the active region of the AlInGaP semiconductor material. This recombination releases energy in the form of photons, producing red light. The specific alloy composition of AlInGaP determines the bandgap energy, which directly defines the wavelength (color) of the emitted light. The seven segments are independent LEDs arranged in a figure-eight pattern; by selectively energizing different combinations of these segments, all numeric digits from 0 to 9 can be formed.

13. Technology Trends

While seven-segment displays remain a robust and cost-effective solution for numeric readouts, the broader trend in display technology is towards higher integration and flexibility. Multi-digit modules with integrated controllers (I2C, SPI) are becoming more common, reducing the microcontroller pin count and software overhead. Furthermore, dot-matrix displays and OLEDs offer alphanumeric and graphical capabilities in similarly sized packages. However, for applications requiring only a simple, bright, reliable, and power-efficient numeric digit, discrete seven-segment LEDs like the LTS-5003AJD, especially those using high-efficiency materials like AlInGaP, continue to be a relevant and optimal choice due to their simplicity, durability, and excellent contrast in various lighting conditions.