LTA-10102KR LED Display Datasheet - 10-Segment Rectangular Bar - AlInGaP Super Red - 2.6V Forward Voltage - 70mW Power Dissipation - English Technical Documentation

1. Product Overview

The LTA-10102KR is a solid-state optoelectronic component designed as a ten-segment rectangular light bar display. Its primary function is to provide a large, bright, and uniform light-emitting area for applications requiring clear visual indicators or illumination. The device is constructed using advanced AlInGaP (Aluminum Indium Gallium Phosphide) semiconductor material specifically engineered for Super Red emission, offering superior performance compared to traditional LED technologies.

The core design philosophy centers on delivering high luminous output with relatively low electrical power requirements. The display features a black face which enhances contrast by minimizing ambient light reflection, paired with white segments that efficiently scatter and emit the generated red light, ensuring excellent visibility even in well-lit environments. This combination makes it suitable for status indicators, panel displays, instrumentation, and various consumer electronics where reliable and bright signaling is critical.

The device is categorized for luminous intensity, meaning units are binned and sorted based on their measured light output at a standard test current. This allows designers to select components with consistent brightness levels, which is crucial for applications involving multiple displays or where uniform appearance is required across a product line.

2. In-Depth Technical Parameter Analysis

2.1 Absolute Maximum Ratings

These parameters define the operational limits beyond which permanent damage to the device may occur. They are not intended for normal operating conditions.

• Power Dissipation per Segment: 70 mW maximum. This is the total electrical power (current multiplied by voltage) that can be safely converted into light and heat within a single segment without risking thermal degradation.
• Peak Forward Current per Segment: 90 mA maximum, but only under pulsed conditions with a 1/10 duty cycle and a 0.1 ms pulse width. This rating is for short-duration, high-current pulses, not for continuous operation.
• Continuous Forward Current per Segment: The base rating is 25 mA at 25\u00b0C. This rating derates linearly at a rate of 0.33 mA per degree Celsius increase in ambient temperature. For example, at 85\u00b0C, the maximum allowable continuous current would be approximately: 25 mA - (0.33 mA/\u00b0C * (85-25)\u00b0C) = 25 mA - 19.8 mA = 5.2 mA. This derating is critical for ensuring long-term reliability.
• Reverse Voltage per Segment: 5 V maximum. Exceeding this voltage in the reverse bias direction can cause junction breakdown.
• Operating & Storage Temperature Range: -35\u00b0C to +105\u00b0C. The device is designed to withstand and operate within this broad temperature range, making it suitable for industrial and automotive applications.

2.2 Electrical & Optical Characteristics (Ta=25\u00b0C)

These are the typical performance parameters measured under specified test conditions, representing the expected behavior of the device.

• Average Luminous Intensity (I_V): 200 \u03bccd (min), 675 \u03bccd (typ) at I_F = 1 mA. This is the measure of visible light output. The wide range indicates the categorization (binning) process; designers must consult specific bin codes for precise intensity values.
• Peak Emission Wavelength (\u03bb_p): 639 nm (typ) at I_F = 20 mA. This is the wavelength at which the spectral power distribution is maximum. It defines the hue of the red color.
• Spectral Line Half-Width (\u0394\u03bb): 20 nm (typ) at I_F = 20 mA. This parameter indicates the color purity. A narrower half-width means a more monochromatic, purer color. 20 nm is characteristic of AlInGaP technology.
• Dominant Wavelength (\u03bb_d): 631 nm (typ) at I_F = 20 mA. This is the single wavelength perceived by the human eye that matches the color of the LED. It is often more relevant for color specification than peak wavelength.
• Forward Voltage per Segment (V_F): 2.0 V (min), 2.6 V (typ) at I_F = 20 mA. This is the voltage drop across the LED when operating. It is crucial for designing the current-limiting circuitry. The typical value of 2.6V is lower than standard InGaN blue/green/white LEDs, leading to lower power consumption for a given current.
• Reverse Current per Segment (I_R): 100 \u03bcA (max) at V_R = 5V. This is the small leakage current that flows when the diode is reverse-biased at its maximum rating.
• Luminous Intensity Matching Ratio: 2:1 (max) for similar light area segments at I_F = 1 mA. This specifies the maximum allowable ratio between the brightest and dimmest segment within a single device or a matched batch, ensuring visual uniformity.

3. Binning System Explanation

The LTA-10102KR employs a categorization system primarily for Luminous Intensity. While the datasheet does not detail specific bin codes, the practice involves testing each manufactured unit at a standard current (e.g., 1mA or 20mA) and sorting them into groups based on the measured light output. This allows customers to order parts from a specific intensity bin, guaranteeing consistency in brightness across their production runs. Designers should contact the component supplier for the available bin code list and their corresponding intensity ranges to ensure the selected part meets the application's brightness requirements.

4. Performance Curve Analysis

The datasheet references typical characteristic curves which are essential for understanding device behavior under varying conditions. While the specific graphs are not included in the provided text, standard curves for such a device would typically include:

• Forward Current vs. Forward Voltage (I-V Curve): This non-linear curve shows how much current flows for a given applied forward voltage. It is fundamental for designing the driver circuit, as a small change in voltage can cause a large change in current. A constant-current driver is highly recommended.
• Luminous Intensity vs. Forward Current: This curve shows that light output increases with current but may become sub-linear at very high currents due to efficiency droop and thermal effects.
• Luminous Intensity vs. Ambient Temperature: For AlInGaP LEDs, light output typically decreases as the junction temperature increases. This curve is vital for applications operating over a wide temperature range to ensure sufficient brightness is maintained at high temperatures.
• Spectral Distribution: A graph showing the relative power emitted across different wavelengths, centered around the peak wavelength of 639 nm with a typical half-width of 20 nm.

5. Mechanical & Package Information

5.1 Package Dimensions

The device is provided in a through-hole package. The dimensional drawing specifies the physical layout. Key notes include: all dimensions are in millimeters (mm), with standard tolerances of \u00b10.25 mm unless otherwise stated. A specific note indicates a pin tip shift tolerance of \u00b10.4 mm, which is important for PCB hole placement and wave soldering processes.

5.2 Pin Connection and Polarity

The LTA-10102KR has a 20-pin configuration. The pinout is organized logically: Pins 1 through 10 are the anodes for segments A through K (note: segment I is typically skipped to avoid confusion with the number 1, hence A, B, C, D, E, F, G, H, J, K). Pins 11 through 20 are the corresponding cathodes in reverse order (K, J, H, G, F, E, D, C, B, A). This arrangement likely simplifies the internal PCB trace routing for a multi-segment display. Each segment is electrically isolated, allowing for individual multiplexing or control.

5.3 Internal Circuit Diagram

The internal structure shows ten independent LED segments. There is no internal current-limiting resistor or multiplexing logic. Each anode-cathode pair must be driven externally. This provides maximum flexibility for the designer but requires an external driver circuit capable of handling the total current if all segments are illuminated simultaneously.

6. Soldering & Assembly Guidelines

The datasheet specifies soldering conditions: 1/16 inch (approximately 1.6 mm) below the seating plane for 3 seconds at 260\u00b0C. This refers to wave soldering parameters for through-hole components. The time (3 seconds) is the maximum contact duration with the solder wave. The temperature (260\u00b0C) is the solder pot temperature. The \"1/16 inch below seating plane\" ensures the solder fillet forms correctly without exposing the plastic body to excessive heat. It is critical to adhere to these limits to prevent thermal damage to the LED chip, wire bonds, or the epoxy package, which can lead to reduced light output, color shift, or catastrophic failure. For manual soldering, a temperature-controlled iron with a quick operation time is recommended.

7. Packaging & Ordering Information

The part number is LTA-10102KR. Standard industry practice would involve packaging these devices in anti-static tubes or trays to prevent physical damage and electrostatic discharge (ESD) during handling and shipping. While not specified in the excerpt, typical packaging quantities are often in reels, tubes, or bulk packs. Designers should confirm the packaging option (e.g., bulk, tape & reel) and minimum order quantity with the distributor or manufacturer.

8. Application Recommendations

8.1 Typical Application Scenarios

• Industrial Control Panels: Status indicators for machinery, process steps, or alarm conditions.
• Test & Measurement Equipment: Level indicators, range selection, or function status.
• Consumer Electronics: Power indicators, mode selectors, or decorative lighting in appliances.
• Audio/Video Equipment: Channel, input, or output level displays.
• Automotive Aftermarket: Custom dashboard or console lighting (must be validated for specific automotive environmental requirements).

8.2 Design Considerations

• Current Driving: Always use a constant-current driver or a current-limiting resistor in series with each segment or a bank of segments. Calculate the resistor value using R = (V_supply - V_F) / I_F. Use the maximum V_F from the datasheet for a safe design to ensure current does not exceed limits if a low-V_F part is used.
• Thermal Management: Although power dissipation is low per segment, consider the total heat generated when multiple segments are on continuously, especially at high ambient temperatures. Ensure adequate ventilation and possibly derate the operating current as per the datasheet.
• Multiplexing: To control 10 independent segments with fewer microcontroller pins, multiplexing is common. Ensure the peak current in the multiplexing scheme does not exceed the peak forward current rating (90 mA at 1/10 duty), and calculate the average current to stay within the continuous rating.
• ESD Protection: While not explicitly stated as sensitive, standard ESD handling precautions for semiconductor devices are recommended during assembly.

9. Technical Comparison & Differentiation

The LTA-10102KR's primary differentiators are its use of AlInGaP Super Red technology and its rectangular bar segment shape.

• vs. Standard Red LEDs (e.g., GaAsP): AlInGaP offers significantly higher luminous efficiency, meaning more light output (brightness) for the same electrical input current. It also provides better color purity and stability over temperature and time.
• vs. Dot Matrix or 7-Segment Displays: The rectangular bar format is ideal for creating bar graphs, progress indicators, or linear level meters. It provides a continuous or semi-continuous visual representation that is more intuitive for showing levels or proportions than discrete digits or dots.
• vs. Backlit LCDs: LED displays like this one are emissive, generating their own light, making them far brighter and more readable in direct sunlight or high-ambient-light conditions compared to transmissive LCDs which require a backlight.

10. Frequently Asked Questions (FAQ)

Q1: What is the purpose of the luminous intensity categorization?

A1: Categorization (binning) ensures brightness consistency. For example, if your design requires a minimum brightness, you can specify a bin code that guarantees all parts meet that threshold, preventing some displays from appearing dimmer than others in the same product.

Q2: Can I drive all 10 segments at their maximum continuous current (25mA) simultaneously?

A2: Yes, electrically you can. However, you must consider the total power dissipation (10 segments * 2.6V * 0.025A = 0.65W) and the resulting temperature rise. At elevated ambient temperatures, you must derate the current as specified to maintain reliability.

Q3: Why are there separate anode and cathode pins for each segment instead of a common anode or cathode?

A3: Individual anode and cathode pins provide maximum flexibility. It allows the designer to use either common-anode or common-cathode multiplexing schemes, or to drive each segment completely independently with its own driver IC, depending on the system architecture.

Q4: Is a heatsink required?

A4: For most low-duty-cycle or low-current applications, a dedicated heatsink is not necessary. The PCB itself acts as a heatsink via the pins. For continuous operation of all segments at high current in a high ambient temperature, thermal analysis of the PCB layout is recommended.

11. Design-in Case Study

Scenario: Designing a battery-powered audio mixer level meter. The LTA-10102KR is an excellent choice for a 10-segment bar graph VU meter. Design Steps:

1. Driver Circuit: Use a dedicated bar graph driver IC. This IC will take an analog input voltage (from the audio signal) and light up a corresponding number of segments. It handles the current sourcing/sinking and often includes logarithmic scaling to match human hearing perception.
2. Current Setting: Configure the driver IC to supply 10-15 mA per segment. This provides good brightness while conserving battery power and staying well within the device's ratings.
3. Power Supply: The mixer likely uses a single supply (e.g., 9V or 12V). The driver IC and the LED forward voltage (2.6V typ) must be compatible with this supply. A voltage regulator may be needed for the driver IC logic.
4. PCB Layout: Place the display close to the driver IC to minimize trace length. Ensure the ground plane is solid to provide a stable return path and some thermal dissipation.

This implementation results in a bright, responsive, and professional-looking level meter with low overall power consumption.

12. Technology Principle Introduction

The LTA-10102KR is based on AlInGaP (Aluminum Indium Gallium Phosphide) semiconductor technology grown on a non-transparent GaAs (Gallium Arsenide) substrate. Here's how it works:

1. Electroluminescence: When a forward voltage is applied across the p-n junction of the AlInGaP material, electrons from the n-type region and holes from the p-type region are injected into the active region.
2. Recombination & Photon Emission: In the active region, electrons recombine with holes. The energy released during this recombination is emitted as a photon (light particle). The specific bandgap energy of the AlInGaP alloy determines the photon's wavelength, which is in the red spectrum (~631-639 nm).
3. Substrate: The GaAs substrate is non-transparent, so the light generated is emitted from the top surface of the chip. The chip is then placed in a reflective cup within the epoxy package to direct more light forward, and the white segment diffuses this light to create a uniform rectangular appearance.

13. Technology Trends

The field of LED displays continues to evolve. While the LTA-10102KR represents a mature and reliable through-hole technology, broader industry trends include:

• Miniaturization & Surface-Mount Technology (SMT): There is a strong shift towards SMT packages (like PLCC, chip LEDs) for automated assembly, reduced board space, and lower profile.
• Increased Efficiency: Ongoing material science research aims to improve the internal quantum efficiency (IQE) and light extraction efficiency (LEE) of AlInGaP and other LED materials, yielding more lumens per watt.
• Integrated Solutions: Driver electronics and control logic are increasingly being integrated either into multi-chip modules or alongside LEDs in smart display modules, reducing external component count.
• Flexible & Conformable Displays: Research into substrates other than rigid PCBs or ceramics may lead to bendable or curved light bar displays in the future.

The LTA-10102KR, with its specific through-hole form factor and proven AlInGaP technology, remains a robust and optimal solution for applications where its particular combination of brightness, form factor, and reliability is required.