LTS-5701AJF 0.56-inch Yellow-Orange Seven-Segment Display Datasheet - Character Height 14.22mm - Forward Voltage 2.6V - Power Consumption 70mW - Technical Documentation

1. Product Overview

LTS-5701AJF is a high-performance, single-digit, seven-segment LED display module. Its primary function is to provide clear, bright numeric and limited alphanumeric character display in electronic devices. Its core technology is based on aluminum indium gallium phosphide (AlInGaP) semiconductor material, which is specifically designed to emit light in the yellow-orange spectrum. Compared to traditional technologies such as gallium phosphide (GaP), this material system is renowned for its high efficiency and excellent brightness. The device features a gray panel with white segment markings, which significantly enhances contrast and readability under various lighting conditions. It is designed in a common anode configuration, which simplifies circuit design in many microcontroller-based applications, as sink current driving is often more straightforward.

1.1 Key Features and Advantages

The display boasts several significant advantages, making it suitable for a wide range of application scenarios:

• Optimal Character Size:With a character height of 0.56 inches (14.22 mm), it offers excellent long-distance visibility while maintaining a compact package size.
• Optical Performance Excellence:Utilizing AlInGaP chips to achieve high brightness and high contrast. Continuous, uniform segment codes ensure character appearance consistency and aesthetics, free from dark spots or irregularities.
• Wide Viewing Angle:The design allows for clear visibility from a broad range of angles, which is critical for panel meters, instrumentation, and consumer electronics.
• Low power consumption operation:It requires only a relatively low forward current to achieve good luminous intensity, resulting in high energy efficiency, making it suitable for battery-powered devices.
• Enhanced reliability:As a solid-state device, it offers high reliability, long operational life, and resistance to shock and vibration compared to mechanical or vacuum fluorescent displays.
• Quality Assurance:Devices are classified (binned) according to luminous intensity to ensure brightness consistency across different production lots, achieving uniformity in the appearance of display panels.

2. In-depth Technical Parameter Analysis

This section provides a detailed and objective interpretation of the electrical and optical parameters specified in the datasheet. Understanding these values 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. Operation at or beyond these limits is not guaranteed, and reliable design should avoid such conditions.

• Power consumption per segment (70 mW):This is the maximum power that a single LED segment can safely dissipate as heat under continuous operation. Exceeding this limit risks overheating and damaging the semiconductor junction, leading to accelerated aging or catastrophic failure.
• Peak forward current per segment (60 mA, duty cycle 1/10, pulse width 0.1ms):This rating allows the use of short pulses of higher current to achieve instantaneous peaks in brightness, such as in multiplexed displays or for highlighting. Strict duty cycle and pulse width limits are crucial; the average current must still comply with the continuous rating.
• Continuous forward current per segment (25 mA):Recommended maximum current for a single segment under steady-state, non-pulsed operation. A linear derating factor of 0.33 mA/°C is specified when the ambient temperature (Ta) exceeds 25°C. This means if the ambient temperature rises to 50°C, the maximum allowable continuous current will be: 25 mA - ((50°C - 25°C) * 0.33 mA/°C) = 25 mA - 8.25 mA =16.75 mA.
• Reverse voltage per segment (5 V):The maximum voltage that can be applied in the reverse bias direction to an LED segment. Exceeding this value may cause breakdown and damage the PN junction. If reverse voltage transients are possible, proper circuit design should include protective measures.
• Operating and Storage Temperature Range (-35°C to +85°C):Defines the environmental limits for reliable operation and non-operational storage.
• Welding temperature (260°C, for 3 seconds):Provides guidance for wave soldering or reflow soldering processes, specifying the maximum temperature at a specific location (approximately 1.59 mm below the mounting plane) for a limited time to prevent damage to the plastic package and internal bonding wires.

2.2 Electrical and Optical Characteristics (at ambient temperature Ta=25°C)

These are typical performance parameters under specified test conditions. They are used for design calculations and performance expectations.

• Average luminous intensity (I_V):At I_F=1mA 320-900 μcd. Oke a na-egosi ịdị mma nke anya mmadụ na-ahụ. Ogologo oge (obere: 320, ihe atụ: 900) na-egosi na enwere usoro nkewa. Ndị na-emepụta ihe ga-eji obere uru mee ihe maka ngụkọ ịdị mma n'ọnọdụ kachasị njọ, iji hụ na a na-ahụ ya n'ọnọdụ niile.
• Peak emission wavelength (λ_p):At I_F=20mA 611 nm (ihe atụ). Nke a bụ ogologo ebili mmiri nke mmepụta spectrum kachasị ike, nke dị na mpaghara odo-ọcha nke spectrum a na-ahụ anya.
• Dominant wavelength (λ_d):At I_F=20mA 605 nm (ihe atụ). Nke a bụ otu ogologo ebili mmiri nke anya mmadụ na-ahụ, nke kwekọrọ na agba nke ìhè LED na-ewepụta. Ọ dị ntakịrị n'okpuru ogologo ebili mmiri kachasị elu, nke a na-ahụkarị maka LED nwere spectrum sara mbara.
• Spectral line half-width (Δλ):At I_F=20mA is 17 nm (typical). This parameter indicates color purity. A value of 17 nm is a medium width, producing saturated but non-monochromatic yellow-orange light.
• Forward voltage per segment (V_F):At I_F=20mA is 2.05V (min), 2.6V (typical). This is the voltage drop across the LED during operation. It is crucial for calculating the current-limiting resistor value: R = (V_{Power supply}- V_F) / I_FUsing typical or maximum values ensures that the current does not exceed the required level.
• Each reverse current (I_R):At V_R=5V is 100 μA (maximum). 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 brightness variation between different segments of the same digit or between different digits in a multi-digit display. A ratio of 2:1 means the brightest segment should not exceed twice the brightness of the dimmest segment, ensuring a uniform appearance.

3. Explanation of the Grading System

The datasheet indicates the device is "classified by luminous intensity." This refers to a post-manufacturing binning or screening process.

• Luminous Intensity Binning:Due to natural variations in semiconductor epitaxial growth and chip manufacturing, the light output of LEDs can differ. After production, the devices are tested and sorted into different bins based on their measured luminous intensity at a standard test current (e.g., 1mA). The specified range of 320 to 900 μcd may encompass multiple bins. For applications requiring strict brightness matching, manufacturers may offer specific bin codes.
• Forward Voltage Screening:Although not explicitly mentioned as a binning parameter, the provided V_Frange (2.05V to 2.6V) is typical. For high-volume or sensitive designs, devices can also be screened by forward voltage to ensure consistency in overall display power consumption and thermal characteristics.

4. Performance Curve Analysis

Although the provided datasheet excerpt mentions "Typical Electrical/Optical Characteristic Curves," the specific graphs are not included in the text. Based on standard LED behavior, these curves typically illustrate the following relationships, which are crucial for understanding device performance under non-standard conditions:

• Forward Current vs. Forward Voltage (I-V Curve):Shows an exponential relationship. The curve shifts with temperature; for a given current, V_FYana raguwa tare da haɓakar zafin jiki.
• Ƙarfin haske vs. Halin yanzu na gaba:Yawanci yana nuna alaƙa kusan layi a ƙaramin halin yanzu, yana iya haifar da jikewa ko raguwar inganci a cikin babban halin yanzu. Ana amfani da wannan zane don zaɓar halin yanzu na aiki bisa ga matakin haske da ake buƙata.
• Ƙarfin haske vs. Yanayin zafin muhalli:Demonstrates how light output decreases with increasing ambient (and junction) temperature. This is crucial for designs operating in high-temperature environments.
• Spectral Distribution:A plot of relative intensity versus wavelength, showing a peak at ~611 nm and a half-width of approximately 17 nm, defining the exact color characteristics.

5. Mechanical and Packaging Information

5.1 Package Dimensions and Pin Definitions

The device is housed in a standard 10-pin, single-digit, seven-segment LED display package. The datasheet provides a detailed dimensional drawing (not copied here), with all critical dimensions given in millimeters. Key features include overall height, width, and depth, digit window size, pin pitch, and mounting plane. Unless otherwise specified, tolerances are typically ±0.25 mm. The pin connection definitions are clearly outlined:

1. Pin 1: Cathode E
2. Pin 2: Cathode D
3. Pin 3: Common Anode
4. Pin 4: Cathode C
5. Pin 5: Cathode D.P.
6. Pin 6: Cathode B
7. Pin 7: Cathode A
8. Pin 8: Common Anode
9. Pin 9: Cathode F
10. Pin 10: Cathode G

The internal circuit diagram shows that the anodes of all segment LEDs (A-G and DP) are internally connected together and linked to two common anode pins (3 and 8), which are also internally connected. This common anode design means that to illuminate a segment, its corresponding cathode pin must be driven low (grounded or connected to a lower voltage), while the anode pin is maintained at a positive voltage through a current-limiting resistor.

6. Soldering and Assembly Guide

Absolute maximum ratings specify soldering conditions: 260°C for 3 seconds, with the measurement point approximately 1.59 mm below the mounting plane. This is the standard reference for wave soldering. For reflow soldering, a standard lead-free temperature profile with a peak temperature not exceeding 260°C is appropriate. Avoiding excessive thermal stress is crucial, as it may lead to epoxy package cracking, damage to the internal die attach, or breakage of the fine bonding wires connecting the chip to the leads. Preheating is recommended to minimize thermal shock. After soldering, the device should be allowed to cool gradually. For storage, maintain a dry, non-condensing environment between -35°C and +85°C to preserve solderability and prevent moisture absorption (which can cause "popcorn" effect during reflow).

7. Application Suggestions

7.1 Typical Application Scenarios

LTS-5701AJF is highly suitable for applications requiring clear and reliable digital readings:

• Test and Measurement Equipment:Digital multimeters, frequency counters, power supplies, sensor reading displays.
• Industrial Control:Panel meters for temperature, pressure, flow, speed, and process variable display.
• Consumer Electronics:Clocks, timers, kitchen appliance displays, audio equipment level meters.
• Automotive Aftermarket:Gauges and displays for auxiliary systems (not suitable for primary instrument clusters due to temperature and reliability certification requirements).
• Medical Equipment:Simple parameter display on non-critical monitoring equipment (requires corresponding regulatory approval).

7.2 Design Considerations and Circuit Implementation

• Current Limiting:A resistor must be connected in series with the common anode or each cathode to limit the forward current to a safe value (e.g., 10-20 mA). The resistor value is calculated using the supply voltage (V_CC), LED forward voltage (V_F) and required current (I_F) calculation: R = (V_CC- V_F) / I_F. Using the maximum V from the datasheet_Fvalue for conservative design ensures the current never exceeds the target value.
• Multiplexing Drive:For multi-digit displays, multiplexing is almost always used to minimize the number of microcontroller pins required. This involves illuminating each digit in rapid sequence. The persistence of vision effect makes the display appear continuously lit. During multiplexing, the peak current per segment can be higher (within the 60mA pulse rating) to compensate for the reduced duty cycle and maintain average brightness. The design must ensure the average current and power dissipation per segment remain within continuous limits.
• Microcontroller Drive:Common anode displays are easily driven by microcontroller port pins configured as open-drain or open-collector outputs, which sink current to ground. Alternatively, dedicated LED driver ICs or transistor arrays (e.g., ULN2003) can be used for higher current capability or simpler logic.
• Viewing Angle and Mounting:When designing the panel cutout and mounting depth, the expected user's viewing angle should be considered to fully utilize the display's wide viewing angle characteristics.

8. Technical Comparison and Differentiation

The primary differentiation of the LTS-5701AJF lies in its use of AlInGaP material to achieve yellow-orange light emission. Compared to traditional GaP yellow LEDs, AlInGaP offers significantly higher luminous efficiency, enabling brighter displays at the same current or achieving equivalent brightness at lower power. Compared to red GaAsP or AllnGaP LEDs, it provides a unique color that may be easier to read under certain ambient light conditions and may be preferred due to specific aesthetic or functional color-coding requirements. The 0.56-inch digit size makes it a common choice for instrument panels, striking a good balance between size and readability.

9. Frequently Asked Questions (Based on Technical Parameters)

Q1: Using a 5V power supply to drive a segment with 15mA, what resistor value should be used?
A1: For safety design, use the maximum V_Fvalue 2.6V: R = (5V - 2.6V) / 0.015A = 2.4V / 0.015A = 160 Ω. The nearest standard values of 150 Ω or 180 Ω are suitable. Be sure to verify the actual brightness and current in the circuit.

Q2: Can I connect the two common anode pins together?
A2: A'a, filaye 3 da 8 suna haɗuwa a ciki. Haɗa su a kan PCB hanya ce ta al'ada, tana taimakawa wajen rarraba kwarara, mai yuwuwa inganta daidaiton haske.

Q3: Yaya ake nuna lamba "7"?
A3: Don nuna "7", ana buƙatar kunna sassan A, B, da C. Don haka, ga tsarin anode gama gari, yi amfani da ƙarfin lantarki mai kyau (ta hanyar resistor mai iyakancewar kwarara) ga anode gama gari, kuma haɗa filayen cathode na A (fil 7), B (fil 6), da C (fil 4) zuwa ƙasa (ƙananan matakin dabaru).

Q4: Why does the maximum continuous current need to be derated above 25°C?
A4: The power dissipation limit is fixed. As the ambient temperature increases, the temperature difference (thermal gradient) between the LED junction and the ambient air decreases, making heat dissipation more difficult. To prevent the junction temperature from exceeding its safe limit, the allowable power dissipation (and thus the current for a given V_F) must be reduced.

10. Practical Design Examples

Scenario: Design a 4-digit voltmeter display.
Using a microcontroller with limited I/O pins. Four LTS-5701AJF displays are connected in a multiplexed configuration. The segment cathodes (A-G, DP) for all four digits are connected in parallel. The common anode pin of each digit is controlled by a separate NPN transistor, driven by a microcontroller pin. The microcontroller uses a timer interrupt to scan through the digits cyclically every 2-5 ms. It calculates the segment data for the currently active digit and outputs it via current-limiting resistors to the port connected to the common cathodes. To maintain good brightness at a 1/4 duty cycle, the peak segment current during its active period may be set to 25-30 mA (well below the 60mA pulse rating), resulting in an average current per segment of about 6-7.5 mA, which is safe and provides sufficient brightness. If the device is expected to operate in a high-temperature environment, the design must include derating calculations.

11. Introduction to Technical Principles

LTS-5701AJF is based on III-V group semiconductor compound – Aluminum Indium Gallium Phosphide (Al_xIn_yGa_1-x-yP). The specific proportions of these elements determine the material's bandgap energy, which directly dictates the wavelength (color) of the emitted light. In this case, the material composition is designed so that its bandgap corresponds to yellow-orange photons (approximately 605-611 nm). When a forward voltage is applied across the PN junction, electrons and holes are injected into the active region. They undergo radiative recombination, releasing energy in the form of light. The use of an opaque GaAs substrate helps absorb stray light and improve contrast. The gray panel and white segments are made from molded epoxy resin with diffusing pigments, which helps to evenly diffuse light across each segment and enhance contrast against the unlit background.

12. Technology Trends

While discrete seven-segment displays remain suitable for many applications, the overall trend in display technology is toward integration and flexibility. This includes:
Integrated:Multi-digit modules with built-in driver ICs (e.g., with SPI/I2C interfaces) are becoming increasingly common, simplifying interfacing with microcontrollers.
Materials:Although AlInGaP is highly efficient for red-orange-yellow light, new materials like InGaN (used for blue/green/white light) offer even higher efficiency. Hybrid displays or full-color addressable LED matrices are becoming increasingly popular due to their ability to display more complex information.
Outline Dimensions:The industry continuously pursues thinner packages, higher brightness (for sunlight readability), and lower power consumption (for portable devices). However, the fundamental simplicity, robustness, and cost-effectiveness of standard seven-segment LEDs like the LTS-5701AJF ensure their continued use in a wide range of applications requiring simple numeric output.