LTD-323JD LED Display Datasheet - 0.3-inch Digit Height - Hyper Red 650nm - 2.6V Forward Voltage - English Technical Document

1. Product Overview

LTD-323JD bụ modul ngosi ọnụọgụ dị elu, 0.3-inch (7.62 mm) ogologo mkpụrụedemede. E mere ya maka ngwa chọrọ ọgụgụ ọnụọgụ doro anya, na-egbuke egbuke na nke a pụrụ ịdabere na ya. Ngwaọrụ ahụ nwere ihu ojii nwere akụkụ ọcha, na-enye ọdịiche dị mma maka ọdịdị agwa kachasị mma na akụkụ nlele sara mbara. Nhazi ya siri ike na-eme ka a nwee ntụkwasị obi ogologo oge n'ọnọdụ ọrụ dị iche iche.

1.1 Uru Isi na Ahịa Ezubere Iche

Uru ndị bụ isi nke ihe ngosi a gụnyere nchapụta ya dị elu, oke ọdịiche dị elu, na obere ike chọrọ. Iji AlInGaP (Aluminum Indium Gallium Phosphide) Hyper Red LED chips na mkpụrụ GaAs na-adịghị ahụ anya bụ isi ihe na-arụ ọrụ ya, na-enye arụmọrụ na-egbuke egbuke na ịdị ọcha agba dị elu ma e jiri ya tụnyere teknụzụ ochie. Nke a na-eme ka ọ dabara maka ọtụtụ ngwa gụnyere ngwa ọrụ mmepụta ihe, akụrụngwa nnwale na nha, ngwa ndị ahịa, dashboard ụgbọ ala (ihe ngosi nke abụọ), na ebe ire ere ebe achọrọ ngosipụta ọnụọgụ doro anya, na-arụ ọrụ nke ọma.

2. Technical Parameter Deep Dive

This section provides a detailed, objective interpretation of the key technical parameters specified in the datasheet.

2.1 Photometric and Optical Characteristics

The optical performance is central to the display's functionality. The typical peak emission wavelength (λp) is 650 nm, which falls within the hyper-red spectrum. The dominant wavelength (λd) is specified at 639 nm. The spectral line half-width (Δλ) is 20 nm, indicating a relatively narrow spectral bandwidth which contributes to color purity. The average luminous intensity (Iv) ranges from a minimum of 200 μcd to a maximum of 600 μcd under a test condition of 1mA forward current. A luminous intensity matching ratio of 2:1 (max) ensures reasonable uniformity between segments. It is important to note that the luminous intensity is measured using a sensor and filter combination that approximates the CIE photopic eye-response curve, ensuring the values are relevant to human perception.

2.2 Electrical Parameters

The key electrical parameter is the forward voltage (Vf) per segment, which has a typical value of 2.6V at a forward current (If) of 20mA. The minimum value is 2.1V. The reverse current (Ir) per segment is a maximum of 100 μA when a reverse voltage (Vr) of 5V is applied. These parameters are critical for designing the appropriate current-limiting circuitry and ensuring proper biasing of the LEDs.

3. Absolute Maximum Ratings and Thermal Considerations

The absolute maximum ratings define the operational limits beyond which permanent damage may occur. The continuous forward current per segment is 25 mA at 25°C, with a derating factor of 0.33 mA/°C. This means the allowable continuous current decreases as ambient temperature increases. The peak forward current per segment is 90 mA, but only under pulsed conditions (1/10 duty cycle, 0.1ms pulse width). The maximum power dissipation per segment is 70 mW. The device can operate and be stored within a temperature range of -35°C to +85°C. For assembly, the maximum solder temperature is 260°C for a maximum of 3 seconds at 1.6mm below the seating plane, which is a standard reflow profile consideration.

4. Binning System Explanation

The datasheet indicates that the device is categorized for luminous intensity. This implies a binning system where units are sorted and sold based on their measured light output at a standard test current (likely 1mA). Bins are defined by minimum and maximum intensity values (e.g., 200-300 μcd, 300-400 μcd, etc.). Designers should specify the required bin or be aware of potential intensity variations when sourcing components for applications requiring uniform brightness across multiple displays. The datasheet does not specify voltage or wavelength binning for this part number.

5. Performance Curve Analysis

While the specific graphs are not detailed in the provided text, typical curves for such a device would include:

• IV Curve (Current vs. Voltage): Shows the exponential relationship between forward voltage and current. The knee voltage (where current begins to rise significantly) is typically around 1.8-2.0V for AlInGaP red LEDs.
• Luminous Intensity vs. Forward Current: A generally linear relationship at lower currents, potentially saturating at higher currents due to thermal effects.
• Luminous Intensity vs. Ambient Temperature: Shows the decrease in light output as junction temperature increases. AlInGaP LEDs typically have a negative temperature coefficient for luminous intensity.
• Spectral Distribution: A plot of relative intensity vs. wavelength, showing the peak at ~650nm and the spectral half-width.

These curves are essential for understanding the device's behavior under non-standard operating conditions and for optimizing drive circuitry for efficiency and longevity.

6. Mechanical and Package Information

The device comes in a standard LED display package. All dimensions are provided in millimeters with a general tolerance of ±0.25 mm unless otherwise specified. The exact footprint and pin spacing are defined in the package drawing, which is crucial for PCB (Printed Circuit Board) layout. The segment arrangement is continuous and uniform.

6.1 Pin Configuration and Polarity Identification

LTD-323JD yana da tsarin anode gama gari mai duplex. Wannan yana nufin akwai filayen anode gama gari guda biyu (daya ga kowane lamba a cikin fakitin lamba da yawa; don lamba guda, ana iya amfani da daya). Pinout kamar haka ne: Pin 5 shine anode gama gari don lamba 2, kuma Pin 10 shine anode gama gari don lamba 1. Cathodes na sashe suna haɗe zuwa filaye: A (pin 3), B (pin 9), C (pin 8), D (pin 6), E (pin 7), F (pin 4), da G (pin 1). Pin 2 an lura da shi azaman "No Pin". Daidaitaccen gano filayen anode da cathode yana da mahimmanci don hana karkatar da LEDs.

7. Soldering and Assembly Guidelines

The key soldering parameter provided is the maximum allowable temperature of 260°C for 3 seconds, measured 1.6mm below the seating plane. This is compatible with standard lead-free reflow soldering profiles. Designers should ensure the thermal profile during assembly does not exceed this limit to avoid damaging the epoxy package or the internal wire bonds. Standard handling precautions for ESD (Electrostatic Discharge) sensitive devices should be observed. Storage should be within the specified -35°C to +85°C range in a dry environment.

8. Application Suggestions

8.1 Typical Application Scenarios

Ideal for any device requiring a bright, clear numeric display. Examples include digital multimeters, frequency counters, clock radios, kitchen appliance timers, HVAC controllers, medical device readouts, and industrial process monitors.

8.2 Design Considerations

• Current Limiting: Always use a series resistor (or constant current driver) for each segment or common anode to set the forward current. Calculate the resistor value based on the supply voltage (Vcc), the typical forward voltage (Vf ~2.6V), and the desired current (e.g., 10-20mA). R = (Vcc - Vf) / If.
• Multiplexing: For multi-digit displays, a multiplexed drive scheme is common to reduce pin count. The common anodes are switched sequentially while the corresponding segment data is applied. Ensure the peak current in this scheme does not exceed the absolute maximum rating.
• Viewing Angle: The wide viewing angle is beneficial but consider the intended user's line of sight during mechanical design.
• Heat Management: While power dissipation is low, ensure adequate ventilation in enclosed spaces, especially when operating near maximum ratings or at high ambient temperatures.

9. Technical Comparison

Compared to older technologies like standard GaAsP (Gallium Arsenide Phosphide) red LEDs, the AlInGaP Hyper Red LED offers significantly higher luminous efficiency, resulting in greater brightness for the same drive current. It also provides better color saturation (purer red) and typically has a longer operational lifetime. Compared to white LEDs used with filters for red displays, the Hyper Red LED is more efficient as it emits the desired color directly, eliminating filter losses.

10. Frequently Asked Questions (Based on Technical Parameters)

Q: What is the purpose of the "No Pin" connection?
A: This is typically an unused pin position in the package, often included for mechanical symmetry or because the package mold is used for multiple device variants with different pinouts. It must not be connected in the circuit.

Q: Can I drive this display with a 5V microcontroller pin directly?
A: No. The forward voltage is only ~2.6V. Connecting 5V directly would cause excessive current, destroying the LED. A current-limiting resistor is mandatory.

Q: What does "categorized for luminous intensity" mean for my design?
A: It means displays from different production batches may have slightly different brightness levels. If visual uniformity across multiple units is critical (e.g., in a multi-digit panel), you should specify a tight bin code or implement software brightness calibration.

Q: Is this display suitable for outdoor use?
A: The operating temperature range extends to -35°C to +85°C, which covers many environments. However, for direct sunlight exposure, consider the potential for UV degradation of the epoxy and ensure the brightness is sufficient for daylight readability. A conformal coating may be necessary for moisture protection.

11. Practical Design Case

Scenario: Designing a simple two-digit counter using the LTD-323JD, driven by a 3.3V microcontroller.
Implementation: Use a multiplexing technique. Connect the two common anode pins (Digit 1 and Digit 2) to two microcontroller GPIO pins configured as open-drain/source outputs. Connect the seven segment cathodes (A-G) to seven other GPIO pins through individual 33Ω current-limiting resistors (calculated for ~20mA: R = (3.3V - 2.6V) / 0.02A = 35Ω; 33Ω is a standard value). The software would alternately turn on one common anode at a time, while setting the segment pins for the digit to be displayed. The refresh rate should be above 60 Hz to avoid visible flicker.

12. Principle Introduction

Na'urar tana aiki bisa ka'idar electroluminescence a cikin semiconductor p-n junction. Lokacin da aka yi amfani da ƙarfin lantarki na gaba wanda ya wuce ƙarfin bandgap, electrons da ramuka suna sake haɗuwa a cikin yanki mai aiki (tsarin AlInGaP multi-quantum well), suna sakin makamashi a cikin nau'in photons. Takamaiman abun da ke ciki na Aluminum, Indium, Gallium, da Phosphide yana ƙayyade ƙarfin bandgap, don haka kuma tsawon zango (launi) na hasken da aka fitar—a wannan yanayin, ja mai tsananin launi a 650 nm. Tushen GaAs marar bayyana yana ɗaukar hasken da ya ɓace, yana inganta bambanci.

13. Trends na Ci gaba

Yarjejeniyar a fasahar nuni na LED tana ci gaba zuwa ga ingantacciyar inganci, ƙarancin amfani da wutar lantarki, da ƙara haɗin kai. Duk da yake nunin 7-segment mai ban mamaki kamar LTD-323JD ya kasance mai dacewa don takamaiman aikace-aikace, akwai sauyi zuwa ga nunin OLED dot-matrix da micro-LED don ƙarin zane-zane masu sarkakiya da sassauci. Duk da haka, don sauƙaƙan karatun lambobi masu inganci, haske mai haske, nunin LED na AlInGaP da sabbin na tushen InGaN za su ci gaba da amfani da su sosai saboda ƙarfin su, tsawon rayuwa, da tsadar kuɗi a cikin samarwa mai yawa. Ci gaban da aka samu a cikin marufi na iya haifar da bayanan martaba mafi sirara da kusurwoyin kallo mafi faɗi.