LTD-5223AJF LED Display Datasheet - 0.56-inch Digit Height - AlInGaP Yellow Orange - 2.6V Forward Voltage - English Technical Document

1. Product Overview

The LTD-5223AJF is a high-performance, seven-segment alphanumeric display module designed for applications requiring clear, bright numeric readouts with low power consumption. Its primary function is to provide a visual numeric output in electronic devices. The core technology utilizes Aluminium Indium Gallium Phosphide (AlInGaP) semiconductor material to produce a distinct yellow-orange light emission. This material system is known for its high efficiency and excellent visibility. The display features a light gray face and white segment color, offering high contrast for optimal legibility under various lighting conditions.

Na'urar an rarrabe ta azaman nau'in cathode na gama gari tare da tsarin maki goma na hannun dama. An ƙera shi don amincin ƙwaƙƙwaran jiki, yana tabbatar da dogon rayuwar aiki da aiki mai daidaito. Kasuwar da aka yi niyya ta haɗa da kwamitun sarrafa masana'antu, kayan aikin gwaji da ma'auni, na'urorin masu amfani da kowane tsarin da aka haɗa inda ake buƙatar ƙaramin, amintaccen, da ingantaccen nuni na lambobi.

2. In-Depth Technical Parameter Analysis

2.1 Optical Characteristics

The optical performance is central to the display's functionality. The key parameters, measured at an ambient temperature (TA) of 25\u00b0C, are as follows:

• Average Luminous Intensity (I_V): Ranges from a minimum of 320 \u00b5cd to a typical value of 700 \u00b5cd when driven at a forward current (I_F) of 1mA per segment. This high brightness level ensures good visibility.
• Peak Emission Wavelength (\u03bb_p): Typically 611 nanometers (nm). This defines the specific point of highest spectral power output in the yellow-orange region of the visible spectrum.
• Spectral Line Half-Width (Δλ): Kusan nanometa 17. Wannan ma'auni yana nuna tsaftar bakan haske ko faɗin bakan hasken da ake fitarwa; ƙunƙuntaccen faɗi yana nuna launi mai cikar gaske, mai tsafta.
• Dominant Wavelength (λ_d): Yawanci nanometa 605. Wannan shine hasashen launi guda ɗaya na idon ɗan adam, wanda ya yi daidai da launin rawaya-orange da ake gani.
• Luminous Intensity Matching Ratio (I_V-m): Maximum 2:1. This specifies the allowable variation in brightness between different segments of the same digit when driven under identical conditions (I_F=1mA), ensuring uniform appearance.

All luminous intensity measurements are performed using a sensor and filter combination calibrated to approximate the CIE photopic eye-response curve, ensuring data relevance to human vision.

2.2 Electrical Characteristics

The electrical parameters define the operating conditions and limits for the device:

• Forward Voltage per Segment (V_F): Typically 2.6V, with a maximum of 2.6V at I_F=20mA. This is the voltage drop across an illuminated segment.
• Reverse Current per Segment (I_R): Maximum 100 \u00b5A when a reverse voltage (V_R) of 5V is applied. This indicates the level of leakage current when the LED is reverse-biased.

2.3 Absolute Maximum Ratings

These are stress limits that must not be exceeded under any circumstances to prevent permanent damage:

• Power Dissipation per Segment: 70 mW.
• Peak Forward Current per Segment: 90 mA (at 1/10 duty cycle, 0.1ms pulse width).
• Continuous Forward Current per Segment: 25 mA. This rating derates linearly from 25°C at a rate of 0.33 mA/°C.
• Reverse Voltage per Segment: 5 V.
• Operating & Storage Temperature Range: -35°C to +85°C.
• Solder Temperature: 260°C for 3 seconds, measured 1/16 inch (approx. 1.6mm) below the seating plane.

3. Binning System Explanation

The datasheet indicates the device is "Categorized for Luminous Intensity." This implies a binning or sorting process based on measured optical output. While specific bin code details are not provided in this excerpt, typical categorization for such displays involves grouping units based on their measured luminous intensity at a standard test current (e.g., 1mA or 20mA). This ensures designers receive displays with consistent brightness levels for a uniform product appearance. Purchasers should consult the manufacturer's full binning specifications for detailed code definitions related to intensity and potentially forward voltage (V_f) to ensure electrical compatibility in their design.

4. Performance Curve Analysis

The datasheet references "Typical Electrical / Optical Characteristic Curves." These graphical representations are crucial for understanding device behavior beyond single-point specifications. Although the specific curves are not displayed in the provided text, they typically include:

• I-V (Current-Voltage) Curve: Shows the relationship between forward current (I_F) and forward voltage (V_F). This is essential for designing the current-limiting circuitry.
• Luminous Intensity vs. Forward Current: Illustrates how light output increases with drive current, helping to optimize the trade-off between brightness and power consumption.
• Luminous Intensity vs. Ambient Temperature: Demonstrates how brightness decreases as the junction temperature rises, which is critical for applications operating in elevated temperature environments.
• Spectral Distribution: A plot of relative intensity versus wavelength, showing the peak (λ_p) and shape of the emitted light spectrum.

Designers must refer to these curves to predict performance under non-standard conditions and to ensure reliable operation across the specified temperature range.

5. Mechanical and Package Information

5.1 Physical Dimensions

The device has a digit height of 0.56 inches (14.22 mm). The package dimensions drawing (referenced but not shown) provides detailed mechanical outlines, including overall length, width, height, segment dimensions, and lead (pin) spacing. All dimensions are specified in millimeters with a standard tolerance of \u00b10.25mm unless otherwise noted. This information is vital for PCB footprint design and ensuring proper fit within the end product's enclosure.

5.2 Pin Connection and Polarity Identification

The LTD-5223AJF is a two-digit, common cathode display with 18 pins. The pinout is as follows:

• Common Cathode (CC): Pins 13 and 14 are the common cathode terminals for Digit 2 and Digit 1, respectively. In a common cathode configuration, all LED segment cathodes for a given digit are connected internally to this single pin. To illuminate a segment, its corresponding anode pin must be driven high (positive voltage through a current-limiting resistor) while its digit's common cathode is pulled low (ground).
• Segment Anodes: Pins 1-12 and 15-18 are the anode connections for the individual segments (A-G and DP) of both digits. The mapping is clearly defined in the pin connection table (e.g., Pin 1: Anode E for Digit 1).
• Right-Hand Decimal Point: The decimal point anodes are specified for each digit (Pins 4 and 9), confirming its position on the right side of the digit.

The internal circuit diagram (referenced) visually confirms this common cathode architecture and the interconnection of segments within each digit.

6. Soldering and Assembly Guidelines

The absolute maximum ratings specify a critical soldering parameter: the leads can be subjected to a temperature of 260°C for a maximum of 3 seconds, measured at a point 1/16 inch (1.6mm) below the seating plane (where the package body meets the PCB). This is a standard reflow soldering profile constraint. To ensure reliability:

• Adhere strictly to this time-temperature profile during reflow soldering processes.
• Guji soldering da hannu kai tsaye zuwa jikin kunshin; yi amfani da zafi kawai ga jagororin.
• Bari na'urar ta sanyaya ta halitta bayan soldering; guji girgiza na thermal.
• Bi da aiki da kayan aiki da haɗawa tare da bin ka'idojin ESD (Electrostatic Discharge) na yau da kullun.
• Ajiye na'urori a cikin zazzabi da aka ƙayyade (-35°C zuwa +85°C) a cikin yanayi mai bushewa kafin amfani.

7. Application Recommendations

7.1 Typical Application Circuits

For common cathode displays like the LTD-5223AJF, two primary driving methods are used:

1. Static Drive: Each segment anode has a dedicated current-limiting resistor and driver pin. The common cathodes are permanently connected to ground. This method is simple but requires many I/O pins (7 segments + DP per digit).
2. Multiplexed (Dynamic) Drive: This is the most common method for multi-digit displays. All segment anodes for the same segment position across digits are connected together. The common cathode of each digit is controlled independently by a transistor or driver IC. The microcontroller rapidly cycles through turning on one digit's cathode at a time while presenting the segment data for that digit on the common anode lines. This significantly reduces the required I/O pins and is highly efficient. The high brightness and good response time of AlInGaP LEDs make them well-suited for multiplexing.

7.2 Design Considerations

• Current Limiting: Always use a series resistor for each segment anode (or common anode line in multiplexing) to limit the forward current to a safe value, typically between 1mA and 20mA depending on the desired brightness and power budget. Calculate the resistor value using R = (V_supply - V_F) / I_F.
• Low-Current Operation: The datasheet highlights excellent performance at currents as low as 1mA per segment. This is a key advantage for battery-powered or energy-sensitive applications.
• Viewing Angle: The wide viewing angle ensures readability from various positions, which is important for panel-mounted equipment.
• Heat Management: While power dissipation is low, ensure the operating ambient temperature does not exceed 85°C. In enclosed spaces or high-temperature environments, consider ventilation.

8. Technical Comparison and Differentiation

The LTD-5223AJF's primary differentiators are its material technology and low-current optimization:

• AlInGaP vs. Traditional Materials: Compared to older GaAsP or GaP LED technologies, AlInGaP offers significantly higher luminous efficiency, resulting in greater brightness for the same drive current or equivalent brightness at lower power. It also provides superior color saturation and stability over temperature and lifetime.
• Low-Current Design: Many displays are characterized at higher currents (e.g., 20mA). The LTD-5223AJF is explicitly tested and selected for excellent characteristics at 1mA, making it a standout choice for ultra-low-power designs where every milliamp counts.
• Uniformity: Features like "Continuous Uniform Segments" and a tight luminous intensity matching ratio (2:1) ensure a professional, consistent appearance across all digits and segments, which is not always guaranteed in lower-cost displays.

9. Frequently Asked Questions (Based on Technical Parameters)

Q: What is the minimum current needed to see the segments illuminate?
A: While the device is tested down to 1mA, segments may be visible at even lower currents, though brightness will be very dim. For reliable operation, design for the specified 1mA minimum.

Q: Can I drive this display with a 3.3V or 5V microcontroller directly?
A: Yes, but you must always use a current-limiting resistor. With a typical V_F of 2.6V, a 5V supply would require a resistor value of approximately (5V - 2.6V) / 0.020A = 120Ω for 20mA drive. For 3.3V logic, the headroom is smaller: (3.3V - 2.6V) / 0.020A = 35Ω. Always verify the actual forward current.

Q: What does "Common Cathode" mean for my circuit design?
A> It means you sink current to ground to turn on a digit. In practice, you connect the common cathode pin to a microcontroller I/O pin (set as output low) or to the collector of an NPN transistor whose emitter is grounded. The microcontroller then switches the transistor on to enable the digit.

Q: How do I achieve uniform brightness when multiplexing?
A> In multiplexed drive, the instantaneous current per segment is higher than the desired average current because each digit is only on for a fraction of the time (duty cycle). For example, to achieve an average of 5mA per segment in a 2-digit multiplex with equal duty cycle, you would drive each segment with approximately 10mA when its digit is active. The peak current must still stay within the absolute maximum rating of 25mA continuous/90mA pulsed.

10. Design and Usage Case Study

Labari: Zana Nunin Ma'aunin Ƙarfin Lantarki Mai Ƙarancin Wuta
A designer is creating a handheld digital multimeter that must operate for extended periods on a single 9V battery. Readability in various lighting conditions is critical. The LTD-5223AJF is an ideal candidate.

Implementation: The designer uses a microcontroller with integrated LCD/segment drivers or a dedicated multiplexing driver IC. They choose to drive each segment at an average current of 2mA to conserve power. For a 2-digit multiplex, the peak current during the active time slot is set to 4mA per segment, well within the device's capabilities. The high luminous intensity at low current (320-700 µcd at 1mA) ensures the display remains clearly visible. The AlInGaP yellow-orange color is chosen for its high contrast against the light gray face and its effectiveness in both dim and bright ambient light. The wide viewing angle allows the user to read the measurement from different angles without losing clarity. The low forward voltage minimizes power loss in the driving circuitry, further extending battery life.

11. Technical Principle Introduction

The core operating principle is based on electroluminescence in a semiconductor P-N junction. The LTD-5223AJF uses AlInGaP (Aluminium Indium Gallium Phosphide) as the active semiconductor material. When a forward voltage exceeding the material's bandgap energy is applied across the junction, electrons from the N-type region recombine with holes from the P-type region. This recombination process releases energy in the form of photons (light). 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, yellow-orange (~605-611 nm). The chips are mounted on a non-transparent GaAs substrate, which helps direct light output upwards through the segment, improving efficiency and contrast. The seven individual segments (A-G) and decimal point (DP) are formed by separate LED chips or chip regions, electrically isolated but physically arranged to form a digit pattern. The common cathode configuration internally connects all the cathodes of the segments within a single digit, simplifying external drive circuitry.

12. Technology Trends and Context

Yayin da LED na nuni na bakwai-ɓangare ke ci gaba da zama mafita mai ƙarfi da araha don karatun lambobi, fannin optoelectronics ya fi girma yana ci gaba da haɓaka. Amfani da AlInGaP yana wakiltar ci gaba akan tsofaffin kayan semiconductor na III-V kamar GaAsP, yana ba da ingantacciyar inganci da ingantaccen launi. Hanyoyin yanzu na fasahar nuni don ƙarin cikakkun bayanai sun haɗa da canzawa zuwa OLEDs ko LCDs na dot-matrix, waɗanda ke ba da cikakken ikon haruffa da zane-zane a cikin fakitin da suka yi kama da girma. Duk da haka, don aikace-aikacen lambobi na keɓe waɗanda ke buƙatar ingantaccen aminci, aiki mai faɗin zafin jiki, haske mai haske, da sauƙi, LED bakwai-ɓangare na nuni kamar LTD-5223AJF suna ci gaba da zama zaɓin da aka fi so. Ci gaban gaba na iya mayar da hankali kan ƙarin ingantattun kayan aiki (kamar ingantaccen InGaN don wasu launuka ko fasahar micro-LED), ƙara rage amfani da wutar lantarki don aikace-aikacen maɓalli na baturi, da haɗa na'urori masu tuƙi kai tsaye cikin fakitin nuni don sauƙaƙe ƙirar tsarin.