LTC-5689KY LED Display Datasheet - 0.56-inch Digit Height - Amber Yellow - 2.6V Forward Voltage - 70mW Power Dissipation - English Technical Document

1. Product Overview

The LTC-5689KY is a high-performance, triple-digit, seven-segment LED display module designed for applications requiring clear, bright numeric readouts. Its primary function is to provide a visual numeric output in electronic devices such as instrumentation, industrial control panels, test equipment, and consumer appliances.

The core advantage of this display lies in its use of AlInGaP (Aluminum Indium Gallium Phosphide) LED technology for the segments. This material system is renowned for producing high-efficiency light emission in the amber/yellow spectrum, offering superior brightness and excellent visibility. The device features a black face with white segments, which creates a high-contrast appearance that enhances readability, especially in various ambient lighting conditions. The continuous, uniform segments ensure a clean and professional character appearance.

The target market includes designers and engineers working on devices where power efficiency, reliability, and clear visual communication are paramount. Its categorized luminous intensity and lead-free, RoHS-compliant package make it suitable for modern, environmentally conscious electronic designs.

2. In-Depth Technical Parameter Analysis

2.1 Photometric and Optical Characteristics

The optical performance is central to the display's functionality. At a standard test current of 1mA, the average luminous intensity per segment has a typical value of 2222 µcd (microcandelas), with a minimum specified value of 800 µcd. This high brightness level ensures the digits are easily visible. The light emitted is characterized by a peak wavelength (λp) and dominant wavelength (λd) of 595 nm, placing it firmly in the amber-yellow region of the visible spectrum. The spectral line half-width (Δλ) is 15 nm, indicating a relatively pure color with minimal spread into adjacent wavelengths. Luminous intensity matching between segments is specified at a ratio of 2:1 or better, ensuring uniform brightness across the display for a consistent look.

2.2 Electrical Parameters and Ratings

Understanding the electrical limits is crucial for reliable operation. The absolute maximum ratings define the operational boundaries:

• Power Dissipation per Segment: 70 mW maximum.
• Continuous Forward Current per Segment (I_F): 25 mA maximum.
• Peak Forward Current per Segment: 60 mA maximum, applicable under pulsed conditions (1 kHz, 10% duty cycle).
• Forward Current Derating: Required above 25°C at a rate of 0.33 mA/°C. This is critical for thermal management.
• Forward Voltage per Segment (V_F): Typically 2.6V at I_F = 20 mA, with a maximum of 2.6V. The minimum is 2.05V.
• Reverse Voltage (V_R): 5 V maximum. Exceeding this can damage the LED junction.
• Reverse Current (I_R): 100 µA maximum at V_R = 5V.

2.3 Thermal and Environmental Specifications

The device is rated for an operating temperature range of -35°C to +105°C, and an identical storage temperature range. This wide range makes it suitable for harsh environments. The solder temperature rating is crucial for assembly: the component can withstand 260°C for 3 seconds at a point 1/16 inch below the seating plane. Adhering to this profile is essential to prevent damage during the reflow soldering process.

3. Binning and Categorization System

The datasheet explicitly states that the device is \"Categorized for Luminous Intensity.\" This means the LEDs are tested and sorted (binned) based on their measured light output at a standard test condition. This process ensures that designers receive components with consistent brightness levels, which is vital for applications where multiple displays are used side-by-side or where a specific minimum brightness is required. While the specific binning codes are not detailed in this excerpt, the typical (2222 µcd) and minimum (800 µcd) values provide the performance window.

4. Performance Curve Analysis

The datasheet references \"Typical Electrical / Optical Characteristic Curves\" which are essential for detailed design work. Although the specific graphs are not provided in the text, such curves typically include:

• Forward Current (I_F) vs. Forward Voltage (V_F): Shows the non-linear relationship, helping to design the current-limiting circuitry.
• Luminous Intensity (I_V) vs. Forward Current (I_F): Illustrates how light output increases with current, aiding in brightness calibration and efficiency calculations.
• Luminous Intensity vs. Ambient Temperature: Demonstrates the derating of light output as temperature rises, important for high-temperature applications.
• Spectral Distribution: A graph showing the relative intensity across wavelengths, confirming the 595 nm peak and 15 nm half-width.

Designers should consult the full datasheet from the manufacturer for these graphs to make precise calculations for their specific operating conditions.

5. Mechanical and Package Information

5.1 Physical Dimensions and Drawing

The display has a digit height of 0.56 inches (14.2 mm). The package dimensions are provided in a drawing with all units in millimeters. Key tolerances are ±0.25 mm unless otherwise specified, and the pin tip shift tolerance is +0.4 mm. This information is critical for designing the printed circuit board (PCB) footprint, ensuring proper fit and alignment during assembly.

5.2 Pinout and Polarity Identification

The device uses a 14-pin dual in-line package (DIP). It is configured as a multiplexed common anode display. This means the anodes of the LEDs for each digit are connected together internally (common), while the cathodes for each segment (A-G, DP) are shared across digits. The pin connection table is provided:

• Pins 1-7: Cathodes for segments A, B, C, D, E, F, G respectively.
• Pin 8: Common cathode for the three decimal points (DP1, DP2, DP3).
• Pins 9, 10, 11: Common anodes for Digit 3, Digit 2, and Digit 1 respectively.
• Pin 12: Common anode for the two right-hand decimal points (DP4, DP5).
• Pins 13, 14: Cathodes for DP5 and DP4 respectively.

The internal circuit diagram visually confirms this multiplexed arrangement, showing three sets of seven-segment LEDs with their anodes tied to digit lines and their cathodes tied to segment lines.

6. Soldering and Assembly Guidelines

As a through-hole component, the primary assembly method is wave soldering or manual soldering. The critical parameter provided is the maximum soldering temperature profile: 260°C for 3 seconds, measured 1.6mm (1/16 inch) below the seating plane. During assembly, the temperature of the component body itself must not exceed the maximum storage temperature of 105°C. Proper handling to avoid mechanical stress on the pins and the epoxy package is recommended. Components should be stored in their original moisture-barrier bags in a controlled environment until use.

7. Packaging and Ordering Information

The part number is LTC-5689KY. The \"KY\" suffix likely denotes the color (Amber Yellow) and possibly other specific attributes. The device is described as a \"AlInGaP Amber Yellow Multiplex Common Anode Right Hand Decimal\" display. Standard packaging for such DIP components is typically in anti-static tubes or trays. Designers should confirm the exact packaging quantity (e.g., 50 pieces per tube) with the distributor or manufacturer.

8. Application Suggestions and Design Considerations

8.1 Typical Application Scenarios

• Test and Measurement Equipment: Digital multimeters, frequency counters, power supplies.
• Industrial Controls: Panel meters for temperature, pressure, speed, or count displays.
• Consumer Appliances: Microwave ovens, audio equipment, older model clocks/timers.
• Automotive Aftermarket: Gauges and readouts where high brightness is needed.

8.2 Critical Design Notes

1. Drive Circuitry: Being a common anode, multiplexed display, it requires a driver IC or microcontroller capable of sink current (to drive the segment cathodes) and source current (to drive the digit anodes). Proper current-limiting resistors are mandatory for each segment cathode line.
2. Multiplexing: The digits are illuminated one at a time in rapid succession. The refresh rate must be high enough (typically >60 Hz) to avoid visible flicker. The duty cycle determines the perceived brightness; peak current can be higher than the DC rating as per the datasheet.
3. Thermal Management: Adhere to the forward current derating curve above 25°C. In high ambient temperature applications, reduce the operating current to stay within the power dissipation limits.
4. Viewing Angle: The wide viewing angle is beneficial, but the PCB layout should position the display for optimal user sight lines.

9. Technical Comparison and Differentiation

Compared to older GaP (Gallium Phosphide) or standard GaAsP (Gallium Arsenide Phosphide) yellow LEDs, the AlInGaP technology in the LTC-5689KY offers significantly higher luminous efficiency and brightness. This results in better visibility in bright conditions or at longer distances for the same drive current. The black face/white segment design provides higher contrast than all-diffused packages. Compared to modern surface-mount device (SMD) seven-segment displays, this through-hole version is easier to prototype with and may be preferred for applications requiring higher robustness against vibration or for manual repair.

10. Frequently Asked Questions (Based on Technical Parameters)

Q: What is the purpose of the peak forward current rating (60mA at 1kHz, 10% duty)?
A: This rating allows you to pulse the LED with a higher current during multiplexing to achieve a higher perceived brightness. Since each digit is only on for a fraction of the time (e.g., 1/3 duty for 3 digits), the average power and heat generation remain within limits, while the instantaneous light output is brighter.

Q: How do I calculate the current-limiting resistor value?
A: Use Ohm's Law: R = (V_supply - V_F) / I_F. For a 5V supply, typical V_F of 2.6V, and a desired I_F of 20mA: R = (5 - 2.6) / 0.02 = 120 Ω. Always use the maximum V_F from the datasheet for a conservative design to ensure current doesn't exceed limits.

Q: Can I drive this display without multiplexing?
A: Yes, but it is inefficient. You would need to connect each digit's common anode to V_supply and control each segment cathode independently for all three digits simultaneously. This requires many more microcontroller pins or driver channels (7 segments x 3 digits = 21 lines vs. 7+3=10 lines for multiplexing).

11. Practical Design and Usage Example

Consider designing a simple 3-digit voltmeter. A microcontroller with an analog-to-digital converter (ADC) reads a voltage. The firmware scales this value and determines which segments to illuminate for each digit (hundreds, tens, units). It then uses a multiplexing routine: it sets the segment pattern on cathode pins 1-7 and 8/13/14 for decimals, then enables the anode for Digit 1 (pin 11) for a few milliseconds. It then changes the segment pattern for the next number and enables Digit 2's anode (pin 10), and so on, cycling continuously. The current-limiting resistors are placed in series with each of the 7 main segment cathode lines (pins 1-7). The brightness can be adjusted by varying the duty cycle or the value of the current-limiting resistors within the specified limits.

12. Technical Principle Introduction

A seven-segment display is an assembly of light-emitting diodes (LEDs) arranged in a figure-eight pattern. By selectively illuminating specific segments (labeled A through G), any numeric digit from 0 to 9 can be formed. The LTC-5689KY contains three such digit assemblies in one package. Multiplexing is a technique where these digits share the same set of segment control lines. Only one digit is powered on at any instant, but by cycling through them rapidly, the human eye perceives all digits as being continuously lit. This greatly reduces the number of required control pins and power consumption. The AlInGaP semiconductor material used emits light when electrons recombine with holes across the material's bandgap, which is engineered to correspond to photons with a wavelength of approximately 595 nm (amber-yellow).

13. Industry Trends and Developments

The trend in display technology is strongly towards surface-mount devices (SMDs) for automated assembly, higher density, and lower profile designs. While through-hole displays like the LTC-5689KY remain vital for robustness, serviceability, and certain industrial applications, new designs often opt for SMD seven-segment modules or increasingly, dot-matrix OLED or LCD displays that offer alphanumeric and graphic capability. However, for pure numeric output where extreme brightness, wide temperature range, and simplicity are key, LED seven-segment displays, especially those using efficient materials like AlInGaP, continue to have a stable market position. Developments focus on increasing efficiency (lumens per watt), improving contrast ratios, and offering wider viewing angles within smaller form factors.