LTS-2301AJR Seven-Segment LED Display Datasheet - 0.28 Inch Character Height - Super Red - 2.6V Forward Voltage - Simplified Chinese Technical Documentation

1. Product Overview

The LTS-2301AJR is a high-performance, single-digit, seven-segment alphanumeric display module. Its primary function is to provide clear, bright numeric and limited alphanumeric character display in a wide range of electronic devices and instruments. Its core application scenarios are situations requiring single-digit readouts, such as panel meters, test equipment, industrial controllers, consumer appliances, or as part of a multi-digit display array.

This device is designed for exceptional readability and reliability. Its light-emitting segments utilize advanced AlInGaP (aluminum indium gallium phosphide) semiconductor technology. This material system is renowned for producing high-efficiency red and amber LEDs, offering superior performance compared to traditional GaAsP or GaP technologies. The display features a gray panel with white segment markings, which significantly enhances contrast and legibility when the segments are illuminated, especially under various ambient lighting conditions.

1.1 Core Advantages and Target Market

The LTS-2301AJR offers several key advantages, making it suitable for demanding applications:

• High Brightness and High Contrast:The AlInGaP chip provides high luminous intensity, while the gray face/white segment design maximizes contrast, ensuring clear visibility.
• Low Power Consumption:It operates efficiently at low forward current, making it ideal for battery-powered devices or applications where energy consumption is a concern.
• Wide Viewing Angle:This design provides consistent brightness and color across a wide viewing angle range, which is crucial for panels viewed from different positions.
• Solid-State Reliability:As an LED-based device, it offers a long operational life, resistance to shock and vibration, and instant-on capability, free from the drawbacks of filament-based or gas-discharge displays.
• Uniformly Lit Segments:The segment design aims to achieve continuous, uniform illumination without dark spots, contributing to a professional appearance.

Target markets include industrial automation, instrumentation, medical equipment, consumer electronics (such as scales or timers), automotive aftermarket displays, and any embedded system requiring a rugged, clear numeric indicator.

2. In-depth Analysis of Technical Parameters

Wannan sashe ya yi bincike cikakke, na gaskiya kan mahimman sigogin na'urar bisa ga takardar ƙayyadaddun bayanai.

2.1 Photometric and Optical Characteristics

Aikin gani shine jigon aikin nuni. Ana auna mahimman sigogi a ƙayyadaddun yanayin gwaji (yawanci zafin yanayi 25°C).

• Matsakaicin Ƙarfin Hasken Fitowa (I_V):Wannan ma'auni ne na ƙarfin hasken da ake ji daga wani yanki. Takardar ƙayyadaddun bayanai ta ƙayyade, a cikin kwararan igiyar ruwa ta gaba (I_F) na 1 mA, mafi ƙarancin ƙima shine 200 µcd, madaidaicin ƙima shine 480 µcd, ba a ƙayyade mafi girman ƙima ba. Madaidaicin ƙima yana nuna haske da ake tsammani a ƙarƙashin yanayin aiki na yau da kullun. Ana yin ma'aunin ƙarfi ta amfani da na'urar firikwensin da aka tace don dacewa da lanƙwasa amsawar idon ɗan adam na photopic (daidaitaccen hasken rana) wanda CIE (International Commission on Illumination) ya ayyana.
• Tsawon Zangon Hasken Kololuwa (λ_p):This is the wavelength at which the light emission spectrum reaches its maximum power. For the LTS-2301AJR, the typical peak wavelength is 639 nanometers (nm), located in the deep red portion of the visible spectrum. This parameter defines the fundamental color of the emitted light.
• Dominant Wavelength (λ_d):Typical value is 631 nm, which is the wavelength of monochromatic light that produces a color sensation closest to the LED's output color. Perceptually, it is often more relevant than the peak wavelength.
• Spectral line half-width (Δλ):This parameter has a typical value of 20 nm, indicating the spectral purity or bandwidth of the emitted light. It is the width of the spectrum at half of its maximum intensity. A narrower full width at half maximum indicates better monochromaticity (color purity) of the light source.
• Luminous Intensity Matching Ratio (I_V-m):This ratio is specified to be a maximum of 2:1, ensuring uniformity across the entire display. This means that when all segments are driven under the same conditions (I_F=1mA) no, kona monsi li jo e suno lili. ona li sama suno suli pi kipisi wan. ni li suli tawa lukin sama.

2.2 Electrical Characteristics

Electrical parameters define the operating boundaries and conditions of the device.

• Forward Voltage per Segment (V_F):The voltage drop across an LED segment when current flows through it. The typical value is 2.6V at a forward current of 20 mA. The minimum value is 2.0V. This parameter is crucial for designing current-limiting circuits (typically a resistor in series with each segment or each digit).
• Reverse Current per Segment (I_R):The maximum leakage current (100 µA) when a 5V reverse voltage is applied. This indicates the quality of the diode in blocking reverse current.
• Continuous Forward Current per Segment:The maximum DC current that can be continuously applied to a single segment is 25 mA at 25°C. This rating decreases linearly (derates) above 25°C, by 0.33 mA for each 1°C increase, to prevent thermal damage.
• Peak Forward Current per Segment:For pulse operation (1/10 duty cycle, 0.1 ms pulse width), one segment can handle a peak current of up to 90 mA. This allows for multiplexing schemes or brief overdrive to increase perceived brightness.
• Power consumption per segment:The maximum power that a single segment can dissipate as heat is 70 mW.

2.3 Thermal and Environmental Ratings

• Operating temperature range:This device is rated for reliable operation at ambient temperatures from -35°C to +85°C.
• Storage temperature range:It can be stored in a non-operating state at temperatures from -35°C to +85°C.
• Soldering Temperature:During assembly, the device can withstand a maximum soldering temperature of 260°C for a maximum duration of 3 seconds, measured at a point 1.6mm below the package seating plane. This is crucial for wave soldering or reflow soldering processes.

3. Binning and Classification System

The datasheet clearly states that the device"is classified by luminous intensity".This refers to the common "binning" practice in LED manufacturing.

Due to inherent variations in semiconductor manufacturing processes, LEDs from the same production batch can have slight differences in key parameters such as luminous intensity, forward voltage, and dominant wavelength. To ensure consistency for end users, manufacturers test and sort (bin) the LEDs into groups where these parameters fall within tighter, predefined ranges.

For the LTS-2301AJR, the primary binning criterion is luminous intensity. While the datasheet provides a broad min/typical range (200-480 µcd), devices shipped for a specific order typically come from a single bin or a combination of adjacent bins to meet a 2:1 matching ratio. The specific bin codes and their associated intensity ranges are usually defined in separate manufacturer documents or specified at the time of ordering. This system allows designers to select parts with the precise brightness level required for their application, ensuring visual consistency, especially when using multiple displays.

4. Performance Curve Analysis

Although specific charts are not detailed in the provided text, the typical datasheet for such devices contains several key performance curves. Based on standard LED behavior, we can infer their importance:

• Relative Luminous Intensity vs. Forward Current (I-V Curve):This graph will show how brightness (expressed in µcd or relative percentage) changes as the forward current (I_F) increases. It is typically nonlinear, showing a region of rapid increase, followed by a region of diminishing returns, and eventually saturating or decreasing due to heating. This curve is crucial for selecting the optimal drive current to achieve the desired brightness without exceeding ratings.
• Forward Voltage vs. Forward Current:This curve shows the relationship between the applied voltage and the current through the LED. It illustrates the exponential I-V characteristic of the diode. A typical V_Fvalue (e.g., 2.6V at 20mA) is a point on this curve.
• Relative Luminous Intensity vs. Ambient Temperature:This graph illustrates how the light output of an LED decreases as the ambient (or junction) temperature increases. AlInGaP LEDs are typically more sensitive to temperature than some other types. Understanding this derating is crucial for applications operating in high-temperature environments to ensure sufficient brightness is maintained.
• Spectral Distribution:A plot of relative optical power versus wavelength, showing a peak at ~639 nm and a spectral width (Δλ) at full width at half maximum (FWHM) of approximately 20 nm.

These curves enable engineers to simulate device behavior under non-standard conditions (different currents, temperatures) and design robust drive circuits.

5. Mechanical and Packaging Information

5.1 Physical Dimensions and Drawings

The device uses a standard 10-pin Single In-Line (SIL) package. The package drawing provides key dimensions for PCB (Printed Circuit Board) layout and mechanical integration:

• Karakter yawanci:Siffar ma'ana ita ce yawanci na harafi na 0.28 inci (7.0 mm).
• Gabaɗaya girman kunshe:Zanen ya ƙayyade tsawon, faɗin, da yawanci na harsashi na filastik, tazarar igiyoyi (fil), da tsawon igiyoyi da kauri.
• Ƙimar izini:Daidaitaccen ƙimar izini na duk ma'auni na layi shine ±0.25 mm (±0.01 inci), sai dai idan an lura da wani siffa na musamman. Wannan bayanin yana da mahimmanci don tabbatar da cewa an ɗora nuni daidai a kan panel ko PCB.

5.2 Pin Connections and Polarity

Wannan nuni yana amfani daCommon cathodeConfiguration. This means the cathodes (negative terminals) of all LED segments are internally connected together and brought out to a specific pin, while the anode (positive terminal) of each segment has its own dedicated pin.

Pin definition (10-pin):
1. Anode E
2. Anode D
3. Common cathode
4. Anode C
5. Anode D.P. (decimal point)
6. Anode B
7. Anode A
8. Common Cathode (Note: Pins 3 and 8 are both common cathodes, possibly internally connected for current distribution)
9. Anode G
10. Anode F

The decimal point is designated as "right-hand decimal point," meaning it is located on the right side of the digit when viewing the display from the front.

5.3 Internal Circuit Diagram

The internal circuit diagram visually represents the electrical connections described above. It shows the seven LED segments (A through G) and one decimal point (DP), each with its anode connected to a separate pin. All cathodes are connected together and linked to the two common cathode pins (3 and 8). This diagram is indispensable for understanding how to multiplex or directly drive the display.

6. Soldering and Assembly Guide

Proper handling during the assembly process is crucial for long-term reliability.

• Reflow soldering/Wave soldering:Strictly adhere to the maximum temperature profile: peak temperature 260°C, duration not exceeding 3 seconds, measurement point 1.6mm below the package body. Exceeding these limits may damage internal bond wires, LED chips, or the plastic package.
• Cleaning:If cleaning is required after soldering, use methods and solvents compatible with the display's plastic material. Avoid ultrasonic cleaning unless explicitly approved, as it may induce mechanical stress.
• ESD (Electrostatic Discharge) Precautions:Although not explicitly stated, LEDs are semiconductor devices and may be sensitive to ESD. It is recommended to implement standard ESD handling procedures (grounded workstation, wrist strap) during assembly.
• Storage Conditions:Store within the specified temperature range (-35°C to +85°C) in a low-humidity environment. Moisture-sensitive devices may require dry packaging; if applicable, consult the manufacturer for the MSL (Moisture Sensitivity Level) rating.

7. Application Suggestions and Design Considerations

7.1 Typical Application Circuit

Common cathode configurations are typically driven in one of two ways:

1. Static Drive:Each segment anode is connected to a driver output (e.g., a microcontroller GPIO pin) through a current-limiting resistor. The common cathode is grounded. To illuminate a segment, its corresponding anode pin is driven high (to a voltage above V_F). This method is simple but uses many I/O pins (8 for segments + DP).
2. Multiplexed Drive:For multi-digit displays or to save I/O pins, multiplexing is used. The anodes of the same segments across multiple digits are connected together. The common cathode of each digit is controlled individually. Digits are illuminated one at a time in rapid sequence (e.g., 100 Hz or faster). The persistence of vision effect makes all digits appear continuously lit. This requires the segment driver to handle the higher peak current needed during the brief on-time (up to the 90mA rating) and careful timing software.

Calculation of Current Limiting Resistor:For static drive of the required forward current (I_F), use Ohm's Law: R = (V_{Power Supply}- V_F) / I_F. For example, with a power supply voltage of 5V, V_F= 2.6V, I_F= 20mA: R = (5 - 2.6) / 0.02 = 120 Ω. A standard 120Ω or 150Ω resistor is suitable. The power rating of the resistor should be at least I_F²* R.

7.2 Design Considerations

• Perspective and Panel Design:Ensure that the product panel or housing does not obstruct the wide viewing angle of the display.
• Brightness Control:Brightness can be controlled by adjusting the forward current (via PWM - Pulse Width Modulation) or by using multiplexing duty cycle. PWM is the preferred method for smooth dimming.
• Thermal Management:In high-brightness or high-temperature applications, ensure adequate ventilation. Derating of continuous current above 25°C must be observed.
• Electrical Noise:In environments with electrical noise (e.g., industrial control), ensure a clean power supply and consider adding filtering to the drive lines to prevent abnormal display behavior.

8. Technical Comparison and Differentiation

Compared to older seven-segment display technologies, the LTS-2301AJR offers distinct advantages by using AlInGaP:

• Compared to standard GaAsP/GaP red LEDs:AlInGaP provides significantly higher luminous efficiency (more light output per mA of current), better temperature stability, and a more saturated "super red" color. This translates to lower power consumption at the same brightness or higher brightness at the same current.
• Compared to LCD:Unlike liquid crystal displays, this LED display is self-emissive, providing excellent visibility in low-light conditions without a backlight. It offers a wider operating temperature range, faster response time (instantaneous switching), and is less prone to image retention or slow response at low temperatures.
• Compared to VFD (Vacuum Fluorescent Display):Ko yake VFD na iya zama mai haske sosai kuma suna da faɗin kallon, amma suna buƙatar ƙarfin wutar lantarki mai girma da rikitarwa (anode +30-50V, wutar lantarki na filament). LTS-2301AJR yana aiki a sauƙaƙan ƙarfin wutar lantarki na DC mai ƙarancin ƙarfi, yana sauƙaƙa ƙirar wutar lantarki kuma yana haɓaka aminci.

Babban abin da ya fi dacewa shi ne cewa na'urar ba ta da launi (ja), yayin da wasu fasahohi na iya samar da launuka daban-daban ko cikakken iyawar launi.

9. Frequently Asked Questions (Based on Technical Parameters)

Tambaya: Zan iya sarrafa wannan nuni kai tsaye tare da fil ɗin microcontroller na 3.3V?
Amsa: Yana iya yiwuwa, amma dole ne ku duba ƙarfin wutar lantarki na gaba. Yawanci V_Fshine 2.6V. Wutar lantarki 3.3V ta bar 0.7V kawai don iyakance ƙarfin wutar lantarki. A cikin buƙatun I_Fshine 10mA, R = (3.3 - 2.6)/0.01 = 70 Ω. Wannan yana yiwuwa, amma haske na iya zama ƙasa da 5V/20mA. Tabbatar cewa fil ɗin microcontroller yana iya samar da ƙarfin wutar lantarki da ake buƙata.

Tambaya: Me yasa akwai fil ɗin cathode gama gari guda biyu (3 da 8)?
A: This is a common design practice for distributing the total cathode current. When all segments and the decimal point are lit, the total current flowing into the common cathode can be as high as 8 * I._FHaving two pins reduces the current density per pin, improves reliability, and aids PCB traces in handling the current.

Q: For the peak current rating, what does "1/10 duty cycle, 0.1ms pulse width" mean?
A: This defines a safe pulsed operating mode. You can apply a current pulse of 90mA to a segment, but the pulse width must not exceed 0.1 milliseconds, and the time from the start of one pulse to the start of the next must be at least 10 times the pulse width (i.e., a 1 ms period). This allows the LED junction to cool between pulses, preventing thermal overload.

Q: How can I achieve uniform brightness if the luminous intensity matching ratio is 2:1?
A: The 2:1 ratio is a maximum specification. In practice, well-binned parts will have much better matching. For critical applications, you can specify tighter bins, or implement individual segment current calibration in software/firmware (e.g., using different PWM duty cycles for each segment) to compensate for minor differences.

10. Ayyukan aiki da yanayin fasaha

10.1 Ka'idoji na asali

The LTS-2301AJR is based on the principle of electroluminescence in a semiconductor p-n junction. The active material is AlInGaP. When a forward voltage exceeding the diode turn-on voltage (approximately 2.0V) is applied, electrons from the n-type region and holes from the p-type region are injected into the active region, where they recombine. This recombination process releases energy in the form of photons (light). The specific composition of the AlInGaP alloy determines the bandgap energy, which directly dictates the wavelength (color) of the emitted light—in this case, red at ~639 nm. The transparent GaAs substrate allows more of the generated light to escape the chip, improving external quantum efficiency and brightness.

10.2 Yanayin fasaha

Amfani da AlInGaP yana wakiltar fasaha mai cikakken ci amma mai inganci don LED na ja da amber. Gabaɗayan trends na masana'antar kayan nunin da ke shafar irin waɗannan samfuran sun haɗa da:

• Haɓaka inganci:Ci gaba da ingantattun kimiyyar kayan aiki da ƙirar guntu suna ci gaba da turawa mafi inganci na lumen kowace watt, yana ba da damar yin nuni mai haske a ƙaramin ƙarfi ko rage zafi.
• Ƙananan girma:Ko da yake inci 0.28 shine daidaitaccen girma, akwai trends zuwa ƙananan tsayin haruffa da kuma siririn siffar marufi don na'urorin ɗaukar hoto da aikace-aikacen yawan bayanai.
• Haɗaɗɗe:Some modern seven-segment modules integrate the driver IC (typically an I2C or SPI-controlled chip) directly onto the display PCB, simplifying the interface to the main system microcontroller to just a few wires.
• Color Options:Although this is a red device, the basic market demands various colors. InGaN-based blue and green LEDs are now highly efficient, and full RGB seven-segment displays are available for multi-color indication.
• Alternative Technologies:OLED (Organic Light-Emitting Diode) and micro-LED technologies are emerging for small displays, offering potential advantages in contrast, viewing angle, and flexibility. However, for many industrial and cost-sensitive applications requiring simple, rugged, bright numeric readouts, traditional LED seven-segment displays like the LTS-2301AJR remain highly reliable and the optimal choice.