LTC-2623JF LED Digital Tube Datasheet - 0.28 Inch Character Height - AlInGaP Yellow Orange - 2.6V Forward Voltage - 70mW Power Consumption - Technical Documentation

1. Product Overview

LTC-2623JF na'urar nuni ce ta lambobi bakwai mai matsayi huɗu mai inganci, wanda aka ƙera don aikace-aikacen da ke buƙatar karatun lambobi a sarari. Babban aikinta shine samar da fitarwa ta lambobi ta gani a cikin na'urorin lantarki. Babban fasahar nuni tana amfani da kayan semiconductor na AlInGaP a matsayin guntu LED, waɗanda aka ɗora akan tushen GaAs marar gani. Wannan zaɓin takamaiman kayan yana da mahimmanci don cimma launin haske na rawaya-orange na musamman na na'urar, inganci mai girma, da haske. An ƙera na'urar nuni tare da haɗin fuskar launin toka da sassan farare, da nufin haɓaka bambanci da iya karantawa a ƙarƙashin yanayi daban-daban na haske. Ana rarrabe ta bisa ƙarfin haske, don tabbatar da daidaiton zaɓi a cikin rukunin samarwa.

1.1 Core Advantages and Target Market

This device possesses several key advantages that make it suitable for a range of professional and industrial applications. Its low power requirement is a significant advantage for battery-powered or energy-conscious equipment. Excellent character appearance, high brightness, and high contrast ensure the displayed digits are easily legible from a distance and under ambient light. A wide viewing angle extends the device's usability, allowing viewing from different positions without significant loss of clarity. The inherent solid-state reliability of LED technology means it has a long operational life and is more resistant to shock and vibration compared to mechanical or other display types. The primary target markets for this display include instrument panels, test and measurement equipment, industrial control systems, medical devices, and consumer electronics requiring reliable, clear, and efficient numeric displays.

2. In-depth and Objective Interpretation of Technical Parameters

The datasheet provides a comprehensive set of electrical and optical parameters that define the operating boundaries and performance of the LTC-2623JF display. Understanding these parameters is crucial for proper circuit design and ensuring long-term reliability.

2.1 Absolute Maximum Ratings

These ratings define the stress limits that may cause permanent damage to the device. They are not intended for normal operating conditions.

• Power dissipation per segment:70 mW. This is the maximum power that a single LED segment can safely dissipate as heat under continuous DC operation. Exceeding this limit may cause thermal damage to the semiconductor junction.
• Peak forward current per segment:60 mA. This rating applies to pulse conditions with a duty cycle of 1/10 and a pulse width of 0.1 ms. It allows for a higher current to pass through for a short period to achieve an instantaneous peak in brightness, which is very useful for multiplexing schemes.
• Continuous forward current per segment:25 mA at 25°C. This is the maximum recommended current for continuous operation at room temperature. The datasheet specifies a derating factor of 0.33 mA/°C above 25°C, meaning the maximum allowable continuous current must be reduced as the ambient temperature increases to prevent overheating.
• Reverse voltage per segment:5 V. Applying a reverse bias voltage exceeding this value may cause breakdown and damage the LED.
• Operating and storage temperature range:-35°C to +85°C. The device is rated for operation and storage within this temperature range.
• Soldering temperature:Maximum 260°C for up to 3 seconds, measured 1.6mm below the mounting plane. This is a key parameter for the reflow soldering process during PCB assembly.

2.2 Electrical and Optical Characteristics

These are typical performance parameters measured at Ta=25°C, providing expected behavior under normal operating conditions.

• Average Luminous Intensity (I_V):In I_F=1mA, it is 320 to 800 μcd. This parameter measures the light output. The wide range indicates the existence of a binning process; devices are classified according to their actually measured intensity.
• Peak Emission Wavelength (λ_p):In I_F=20mA, it is 611 nm (typical). This is the wavelength at which the light output power is greatest. For this AlInGaP device, it falls within the yellow-orange region of the visible spectrum.
• Spectral Line Half-Width (Δλ):17 nm (typical value). This indicates the spectral purity or bandwidth of the emitted light. A smaller value means the output light is closer to monochromatic (purer color).
• Dominant wavelength (λ_d):605 nm (typical value). This is the single wavelength that the human eye perceives as the closest match to the color of the light source, closely related to the peak wavelength.
• Forward voltage per segment (V_F):In I_FAt =20mA, it is 2.05V to 2.6V. This is the voltage drop across the LED during operation. It is crucial for designing the current limiting circuit. This range accounts for normal manufacturing variations.
• Reverse Current per Segment (I_R):At V_R=5V, it is 100 μA (max). This is the small leakage current that flows when the LED is reverse-biased within its maximum ratings.
• Luminous Intensity Matching Ratio (I_V-m):2:1 (maximum). This parameter specifies the maximum allowable ratio between the brightest segment/digit and the darkest segment/digit within a single device to ensure uniform appearance.

3. Mechanical and Packaging Information

The physical structure and dimensions of the display are crucial for its mechanical integration into the final product.

3.1 Package Dimensions

The LTC-2623JF utilizes a standard Dual In-line Package (DIP) outline suitable for through-hole PCB mounting. A key dimensional feature is the 0.28-inch (7.0 mm) character height. All dimensions provided in the drawing are in millimeters, with standard tolerances of ±0.25 mm unless otherwise noted. Designers must refer to the exact dimensional drawing to determine the precise location of mounting holes and clearance for the display body.

3.2 Pin Connection and Polarity Identification

O le masini e faʻaaogaina le 16 pine faʻatulagaina. E faʻaaogaina le fausaga faʻateleina anode masani. O lona uiga o anode LED o numera taʻitasi e fesoʻotaʻi faʻatasi i totonu (faʻataʻitaʻiga, pine 1 o le anode masani mo le numera 1, pine 14 o le anode masani mo le numera 2, ma isi), ae o le cathode o vaega taʻitasi (A-G, DP, ma vaega colon L1-L3) e fefaʻasoaaʻi i numera taʻitasi. O lenei mamanu e faʻaitiitia ai le numera o pine avetaʻavale manaʻomia mai le 32 (4 numera * 8 vaega) i le 16, ma mafai ai ona faʻateleina le lelei. O le laulau faʻamatalaga pine e faʻailoa manino ai le galuega o pine taʻitasi, e aofia ai ni naiLeai se Fesoʻotaʻiga(NC) pin and a position without a physical pin (pin 10). Correctly identifying the common anode pins and segment cathode pins is crucial for proper circuit design and software control.

3.3 Internal Circuit Diagram

The internal circuit diagram visually illustrates the multiplexed common-anode architecture. It shows the four common anode nodes (one for each digit) and how each segment and colon cathode is connected to the corresponding LEDs across all four digits. This diagram is invaluable for understanding the electrical topology required to drive the display correctly. It confirms that to illuminate a specific segment on a specific digit, its corresponding common anode pin must be driven high (or connected to Vcc via a current source) while the desired segment cathode pin is driven low (sinking current to ground).

4. Soldering and Assembly Guide

Proper handling during the assembly process is crucial for reliability.

4.1 Reflow soldering parameters

The datasheet clearly specifies the maximum allowable thermal profile for soldering: a peak temperature of 260°C for a maximum duration of 3 seconds, measured 1.6mm below the mounting plane (typically at the PCB surface). This parameter must be strictly adhered to when setting the reflow oven profile. Exceeding these limits may damage internal wire bonds, age the LED epoxy lens, or cause package delamination.

4.2 Precautions and storage conditions

• ESD (Electrostatic Discharge):Ko da ba a bayyana shi a sarari ba, LED na'urar semiconductor ce, wacce za ta iya zama mai saurin kamuwa da ESD. Ana ba da shawarar yin amfani da daidaitattun hanyoyin sarrafa ESD (amfani da bel ɗin wuyan hannu mai kasa, katifa mai hana tashin hankali, da kuma marufi mai ɗaukar wutar lantarki).
• Tsaftacewa:If cleaning is required after soldering, use methods and solvents compatible with plastic packaging and epoxy lenses. Avoid ultrasonic cleaning that may cause microcracks.
• Storage:The device should be stored within its specified temperature range (-35°C to +85°C), preferably in a low-humidity, anti-static environment to prevent moisture absorption and terminal oxidation.

5. Application Recommendations

5.1 Typical Application Scenarios

LTC-2623JF is highly suitable for any application requiring bright, reliable multi-digit numeric displays. Common uses include: digital multimeters and clamp meters, frequency counters, process timers and counters, temperature controllers, electronic scales, medical monitoring devices (such as blood pressure monitors), automotive diagnostic tools, and industrial control panel readouts.

5.2 Design Considerations

• Iyakancewar Kwarara:LED is a current-driven device. A current-limiting resistor (or constant current drive circuit) must be connected in series in each common anode or segment cathode path (depending on the drive topology) to set the operating current. The resistor value is calculated using Ohm's law: R = (V_{Power Supply}- V_F) / I_FFor conservative design, please use the maximum V from the datasheet._Fvalue (2.6V).
• Multiplexing drive circuit:为了仅用16个引脚控制4位数字，需要使用多路复用技术。微控制器依次激活一个数字的公共阳极，同时输出该数字的段码图案。这个过程以高频率（通常>100Hz）进行，以产生所有数字同时点亮的错觉。驱动器必须能够提供点亮一个数字所有段所需的峰值电流。
• Perspective and Installation:Consider the viewing position of the target user. A wide viewing angle is beneficial, but the display should be installed directly facing the viewing direction for optimal brightness.
• Thermal Management:Although power consumption is low, ensure sufficient ventilation around the display when operating in high ambient temperatures or when driven at higher currents to remain within the derated current limits.

6. Technical Comparison and Differentiation

LTC-2623JF primarily distinguishes itself through its use of AlInGaP technology and specific performance characteristics.

• Compared to standard GaAsP or GaP LEDs:AlInGaP technology offers significantly higher luminous efficacy, resulting in higher brightness at the same drive current. It also provides better temperature stability and a longer operational lifetime.
• Compared to displays with larger or smaller character heights:The 0.28-inch character height strikes a balance between readability and compactness, positioned between the smaller 0.2-inch displays used for portable devices and the larger 0.5-inch or 1-inch displays used for panel mounting.
• Comparison with Monochrome vs. Multi-color Displays:This is a monochrome yellow-orange display. For applications requiring status indication (e.g., red for alarm, green for normal), a multi-color or dual-color display would be more suitable.
• Comparison with Common Cathode Configuration:The selection of common anode is usually determined by the driving circuit. Microcontrollers with open-drain/sink capability are more common, making common anode displays a popular choice as they allow the MCU to directly sink the segment current.

7. Frequently Asked Questions Based on Technical Parameters

Q: Why is there a range for luminous intensity (320-800 μcd)?
A: This indicates that the device is sold in bins based on luminous intensity. The manufacturer tests and classifies LEDs according to their actual output. You can specify a narrower binning during production runs for a more uniform display appearance.

Q: Can I drive this display with a 5V power supply?
A: Yes, but a current-limiting resistor must be used. For example, to operate at I_F=20mA, V_FTo drive one segment with a 5V supply under the condition of 2.4V: R = (5V - 2.4V) / 0.02A = 130 ohms. Standard 120 or 150 ohm resistors are suitable.

Q: What does "multiplexed common anode" mean for my software?
A: Your software must implement a display refresh routine. In a loop, it will: 1) Turn off the anode drive for all digits. 2) Output the segment pattern (cathode data) for digit 1. 3) Turn on the anode drive for digit 1. 4) Wait for a short time (e.g., 2-5 milliseconds). 5) Repeat steps 1-4 for digit 2, digit 3, digit 4, then loop back to digit 1.

Q: Peak forward current is 60mA, but continuous current is only 25mA. Can I use 60mA continuously?
A: No. The 60mA rating applies to conditions of low duty cycle (10%), very short pulses (0.1ms width). Using 60mA continuously will far exceed the 70mW power dissipation rating and will quickly damage the LED segment.

8. Practical Design and Usage Cases

Case: Design a 4-digit digital voltmeter reading
A designer is creating a benchtop power supply and needs a clear voltage reading. He selected the LTC-2623JF for its high brightness and good readability. The microcontroller has 16 available I/O pins, which exactly matches the number of pins on the display. The designer uses 8 pins configured as outputs to sink segment currents (A, B, C, D, E, F, G, DP). Another four pins are configured as open-drain outputs to supply current to the four common anodes (each through a small transistor to handle the cumulative segment current). The remaining 4 pins are unused NC pins. Software is written to multiplex the display, read a value from the ADC, and convert it into a 7-segment code pattern. Current-limiting resistors are placed on the common anode lines (or segment lines, depending on the chosen topology). The gray panel/white segment design provides excellent contrast on the power supply's metal panel.

9. Introduction to Principles

LTC-2623JF's operating principle is based on the electroluminescence of a semiconductor p-n junction. When a forward voltage exceeding the diode's turn-on voltage (approximately 2.0-2.6V for this AlInGaP material) is applied, electrons from the n-type region and holes from the p-type region are injected into the junction area. When these carriers recombine in the active region of the semiconductor, energy is released in the form of photons (light). The specific wavelength (color) of the emitted light is determined by the bandgap energy of the semiconductor material. The bandgap of AlInGaP corresponds to the red to yellow-green spectrum; the precise composition in this device is tuned for yellow-orange emission (605-611 nm). The seven-segment format is created by arranging multiple independent LED chips (or chip sections) into the classic "8"-shaped pattern, with each segment being electrically isolated so it can be controlled independently or via a multiplexing scheme.

10. Development Trends

The development of displays like the LTC-2623JF follows the broader trends in optoelectronics. Ongoing directions for development includeHigher efficiency, meaning more light (lumens) per watt of electrical input, which is crucial for battery life and energy savings.Improved color rendering and saturationIt is also an area of development, though less critical for monochrome digital displays. For alphanumeric or multicolor applications, the trend is towardhigher pixel density(more segments or dot-matrix elements in the same area) and the integration ofmultiple colors or full RGB capabilityIntegrated into a single package. Another important trend is the shift from through-hole packages (such as this DIP) toSurface-mount devices (SMD)packages, which allow for smaller, lighter, and more automated assembly. Furthermore,Driver electronics(e.g., constant current drivers, multiplexers, or even simple controllers) are increasingly integrated directly with the display module, simplifying the design task for the end engineer and reducing the component count on the main PCB.