LSHD-7503 0.3-inch Single Digit Red LED Display Datasheet - Character Height 7.62mm - Forward Voltage 2.6V - Power Consumption 75mW - Technical Documentation

1. Product Overview

LSHD-7503 na'urar nuni ce ta lamba guda ɗaya ta LED mai amfani da ƙwayar LED ja mai haske AlInGaP. Ana amfani da ita musamman a cikin na'urorin lantarki inda ake buƙatar karatun lambobi masu haske, inda bayyanawa da amincin suke da muhimmanci. Na'urar tana amfani da fuskar allo mai launin toka mai haske da tsarin sassa fari, wanda ke ba da bambanci mai kyau ga hasken ja da ake fitarwa. Tsayin harafinta na 0.3 inci (7.62 mm) ya sa ta dace da aikace-aikacen da ke da ƙarancin sarari, yayin da take kiyaye karantawa mai kyau.

1.1 Core Advantages and Target Market

Wannan na'urar nuni tana da fa'idodi masu mahimmanci da yawa waɗanda ke ayyana matsayinta a kasuwa. Tana ba da daidaiton sassa mai kyau, yana tabbatar da cewa duk lambobin suna da haske iri ɗaya. Ƙarancin amfani da wutar lantarki da ƙarfin haske mai girma suna sanya ta mai inganci kuma mai bayyanawa. Tare da fa'idar kallon faɗi da amincin ƙwaƙƙwaran yanayi, an tsara ta don aiki na dogon lokaci a cikin na'urorin lantarki na masu amfani da na masana'antu. Manyan kasuwannin manufa sun haɗa da na'urorin sarrafa ofis, na'urorin sadarwa, allunan kayan aikin ma'auni, kayan aikin gida, da sauran aikace-aikacen da ke buƙatar mai nuna lamba guda ɗaya mai aminci.

2. Technical Parameters: In-depth and Objective Interpretation

The following section provides a detailed analysis of the device's electrical and optical characteristics based on the datasheet.

2.1 Photometric and Optical Characteristics

Luminous intensity is a key parameter. At a forward current (I_F) of 1 mA, the typical average luminous intensity is 5400 µcd, with a minimum of 320 µcd and a maximum of 923 µcd. At 10 mA, the typical value increases significantly to 12000 µcd, indicating its high efficiency. The typical dominant wavelength (λ_d) is 624 nm, the peak emission wavelength (λ_p) is 632 nm, and the spectral half-width (Δλ) is 20 nm, which defines its pure red color point. The luminous intensity matching ratio between segments is specified to be a maximum of 2:1, ensuring visual uniformity.

2.2 Electrical Parameters

The forward voltage (V_F) at I_FThe typical value is 2.6V at = 20 mA, with a tolerance of ±0.1V. Designers must consider this range to ensure proper current regulation. Reverse current (I_R) is a maximum of 100 µA at a reverse voltage (V_R) of 5V. It must be noted that the 5V reverse voltage rating is for leakage current testing only; the device should not be operated under continuous reverse bias.

2.3 Absolute Maximum Ratings and Thermal Considerations

Absolute maximum ratings define operational limits. The power dissipation per LED chip is 75 mW. The continuous forward current per chip is 25 mA at 25°C, derating linearly by 0.28 mA/°C above 25°C. A peak forward current of 90 mA is allowed under pulse conditions (1/10 duty cycle, 0.1 ms pulse width). The operating and storage temperature range is -35°C to +85°C. Exceeding these ratings, especially current and temperature, will accelerate performance degradation and may lead to premature failure. Soldering conditions are specified as 260°C for 3 seconds at 1/16 inch (approximately 1.6 mm) below the seating plane.

3. Grading System Description

The datasheet clearly states that the device is "binned for luminous intensity." This means the devices are sorted and grouped (binned) based on their measured light output at a standard test current. This process ensures customers receive displays with consistent brightness levels. While this excerpt does not detail the specific bin codes, it is strongly recommended to use displays from the same bin within a single assembly to avoid perceptible brightness differences between adjacent digits (uneven shading).

4. Performance Curve Analysis

Although the specific graphical curves are not reproduced in the provided text, the datasheet references "Typical Electrical/Optical Characteristic Curves." Typically, such curves for LED displays include:Forward Current vs. Forward Voltage (I-V Curve): It shows a nonlinear relationship, which is crucial for designing constant current drivers.Luminous Intensity vs. Forward Current: It demonstrates how light output increases with current, often showing saturation at higher currents.Luminous Intensity vs. Ambient Temperature: It illustrates that light output decreases as the junction temperature rises, highlighting the importance of thermal management.Spectral Distribution: A plot of relative intensity versus wavelength, centered in the range of 624-632 nm.

5. Mechanical and Package Information

5.1 Dimensions and Tolerances

All package dimensions are provided in millimeters. Unless otherwise specified, the general tolerance is ±0.25 mm. Key mechanical considerations include: a pin tip offset tolerance of ±0.4 mm. The recommended PCB hole diameter for pins is 1.0 mm. Specific quality limits are set for foreign matter on segments (≤10 mil), surface ink contamination (≤20 mil), bubbles within segments (≤10 mil), and reflector bending (≤1% of its length).

5.2 Pin Connections and Polarity Identification

This display uses a dual in-line package with 10 pins. It is acommon cathodeDevice. The internal circuit diagram shows that the anodes of all segments are individually accessible, while the cathodes of all LEDs are connected together. Pin 1 and Pin 6 are both common cathode connections. Pin definitions are as follows: Pin 1: Common Cathode, Pin 2: Anode F, Pin 3: Anode G, Pin 4: Anode E, Pin 5: Anode D, Pin 6: Common Cathode, Pin 7: Anode DP (Decimal Point), Pin 8: Anode C, Pin 9: Anode B, Pin 10: Anode A. The "Rt. Hand Decimal" note indicates the decimal point is on the right side of the digit.

6. Soldering and Assembly Guidelines

6.1 Soldering Process

The specified soldering condition is 260°C for 3 seconds, measured at a point 1.6 mm (1/16 inch) below the mounting plane of the display body. This is typical for wave soldering or hand soldering parameters. During this process, the temperature of the component body itself must not exceed the maximum storage temperature rating.

6.2 Storage Conditions

For optimal storage life, the LED display should be stored in its original packaging. Recommended storage conditions are a temperature between 5°C and 30°C and relative humidity below 60% RH. Failure to meet these conditions may lead to pin oxidation, requiring replating before use. Long-term, large-quantity inventory is discouraged. If the original sealed package is opened and the components are not used within 168 hours (7 days, MSL Level 3), or if an unsealed package has been stored for more than 6 months, it is recommended to bake at 60°C for 48 hours before assembly, and assembly should be completed within one week.

7. Application Recommendations

7.1 Typical Application Scenarios

This display is suitable for general electronic equipment, including office equipment (calculators, copier displays), communication equipment, household appliances (microwave ovens, washing machine timers), and instrumentation. Without prior consultation and certification, it is not suitable for applications where failure could endanger life or health (aviation, medical systems, safety equipment).

7.2 Key Design Considerations

• Drive Circuit: It is strongly recommended to use constant current drive to maintain brightness consistency and service life. The circuit design must ensure the provision of the intended current across the entire forward voltage range (2.5V to 2.7V).
• Protection: The circuit must be protected against reverse voltage and transient voltage spikes during power-on/power-off to avoid damage caused by metal migration and increased leakage current.
• Thermal Management: The operating current must be derated according to the maximum ambient temperature. Excessive current or high temperature will lead to severe luminous decay.
• Mechanical Assembly: Avoid using tools or methods that apply abnormal force to the display body. If a decorative film is attached, ensure that the film is not displaced by directly pressing on the front panel.
• Binning for Multi-digit Displays: When assembling multiple digits in one unit, always use displays from the same luminous intensity bin to ensure uniform appearance.

8. Technical Comparison and Differentiation

Compared to older technologies like GaAsP (Gallium Arsenide Phosphide) red LEDs, the AlInGaP technology used in the LSHD-7503 offers significantly higher luminous efficiency and brightness. This results in better visibility under lower current or high ambient light conditions. The light gray panel/white segment design provides higher contrast when the LED is off compared to fully diffused packages, enhancing aesthetics. The common cathode configuration offers design flexibility for certain driving ICs. Its 0.3-inch size fills a market gap between smaller, harder-to-read displays and larger, higher-power-consumption displays.

9. Frequently Asked Questions (Based on Technical Parameters)

Q: What is the purpose of the two common cathode pins (Pin 1 and Pin 6)?
A: This is standard design practice for multi-segment displays. It provides two connection points for the common return path, aiding PCB layout, reducing current density in a single pin, and improving reliability.

Q: Can I drive this display with a 5V power supply and a simple current-limiting resistor?
A: Yes, but careful calculation is required. Using V_{power supply}= 5V, V_F= 2.6V, I_F= 10 mA, the resistance value should be R = (5 - 2.6) / 0.01 = 240 Ω. You must recalculate for the maximum V_F(2.7V) to ensure the minimum current is acceptable, and consider the power dissipation in the resistor.

Q: Why is the reverse voltage rating only 5V, what happens if it is exceeded?
A: AlInGaP LEDs have a relatively low reverse breakdown voltage. Exceeding 5V, even momentarily, can cause immediate catastrophic failure of the PN junction.

Q: What does "crosstalk specification ≤ 2.5%" mean?
A: This refers to the undesired illumination of a segment that should be off, due to electrical leakage or optical coupling from adjacent powered segments. A value below 2.5% ensures good visual separation between the lit and unlit states.

10. Practical Application Case Analysis

Yanayi: Zana nuni mai sauƙi na lokaci na lamba.Mai zane yana buƙatar allunan lamba guda biyu don nuna mintuna daga 00 zuwa 99. Sun zaɓi na'urorin nuni LSHD-7503 guda biyu. Da farko, sun tabbatar lokacin sayayya an ƙayyade cewa na'urorin biyu sun fito ne daga rukunin haske iri ɗaya. Kewayen yana amfani da microcontroller, wanda filayen tuƙi na sashe suke haɗuwa ta hanyar juriya mai iyakancewar ƙarfi ko jerin tuƙa mai ƙarfi daidai zuwa anode (fil 2, 3, 4, 5, 7, 8, 9, 10) na kowane nuni. Fil ɗin cathode gama-gari (1 da 6) na kowane allon lamba an haɗa shi da fil ɗin microcontroller keɓaɓɓe wanda aka saita azaman fitarwa mai zubewa/buɗe, don haka ya samar da dubawa mai ƙarfi. Software yana kunna allon lamba ɗaya a cikin sauri (misali 100Hz) a kewayen. Tsarin PCB yana bin ƙaddarar rami mai girman 1.0 mm, kuma yana tabbatar cewa jikin nuni bai fuskanci damuwa na injina ba yayin haɗawa. Samfurin ƙarshe yana ba da karatun lamba mai haske, daidaitacce, kuma abin dogaro.

11. Brief Introduction to Working Principle

LSHD-7503 ya dogara ne akan ka'idar hasken lantarki na semiconductor. Layer na AlInGaP epitaxial yana girma akan substrate na GaAs. Lokacin da ake amfani da ƙarfin lantarki mai kyau wanda ya wuce ƙimar kofa, ana shigar da electrons da ramuka cikin yankin aiki kuma suna haɗuwa a ciki. Wannan tsarin haɗuwa a cikin kayan AlInGaP yana sakin makamashi galibi a cikin sigar photons na kewayon tsawon rawaya ja (kimanin 624-632 nm). Kowane ɗaya daga cikin sassan bakwai (da maƙasudin goma) ya ƙunshi ɗaya ko fiye da waɗannan ƙananan guntu na LED. Ta hanyar zaɓin amfani da ƙarfin lantarki zuwa filayen anode waɗanda suka dace da sashe A zuwa G da DP, yayin da ake haɗa cathode gama-gari zuwa ƙasa, ana iya samar da haruffa na lamba takamaiman (0-9).

12. Technology Trends and Development

Duk da cewa nuni na rarrabuwar LED kamar LSHD-7503 har yanzu suna dacewa a wasu aikace-aikace, babban yanayin fasahar nuni shine haɗawa da ƙanƙanta. Masu nuni na LED matrix da OLED suna ba da sassauci mafi girma don nuna haruffa lambobi da zane-zane. Bugu da ƙari, na'urorin da aka ɗora a saman (SMD) suna ƙara maye gurbin irin waɗannan nau'ikan ramuka don haɗawa ta atomatik. A cikin kayan, AlInGaP har yanzu shine babbar fasahar LED ja da amber mai inganci, ko da yake bincike na ci gaba yana mai da hankali kan haɓaka inganci, rage karkatar da tsawon rawaya tare da zafin jiki, da rage farashin samarwa. Duk da haka, don mai nuna lamba ɗaya mai sauƙi, ƙarancin farashi, na'urori kamar LSHD-7503 suna ci gaba da samar da madaidaicin mafita kai tsaye.