LTC-5653KF 0.56-inch Quad Digit LED Display Datasheet - 14.22mm Digit Height - Yellow Orange Color - English Technical Document

1. Product Overview

The LTC-5653KF is a high-performance, four-digit, seven-segment LED display module designed for applications requiring clear numeric readouts. Its primary function is to provide a bright, legible display for instruments, control panels, test equipment, and consumer electronics where numeric data presentation is critical.

The core advantage of this device lies in its use of advanced AlInGaP (Aluminum Indium Gallium Phosphide) semiconductor technology for the light-emitting chips. This material system is known for its high efficiency and excellent color purity in the red to yellow-orange spectrum. The display features a gray faceplate with white segment markings, which significantly enhances contrast and readability when the segments are illuminated, especially under various ambient lighting conditions.

The target market for this component includes industrial automation, medical instrumentation, automotive dashboard sub-displays, point-of-sale terminals, and laboratory equipment. Its design prioritizes reliability, long operational life, and consistent optical performance, making it suitable for both commercial and industrial-grade applications.

2. Technical Parameters Deep Objective Interpretation

2.1 Photometric and Optical Characteristics

The optical performance is defined under standard test conditions at an ambient temperature (T_A) of 25\u00b0C. The key parameters are:

• Average Luminous Intensity (I_V): This is the measure of the perceived power of light emitted by a segment. The typical value is 2222 \u00b5cd (microcandelas) when driven at a forward current (I_F) of 1mA. The minimum guaranteed value is 800 \u00b5cd. This high brightness ensures visibility from a distance and in well-lit environments.
• Peak Emission Wavelength (\u03bb_p): The wavelength at which the emission spectrum reaches its maximum intensity. For this Yellow Orange device, the typical value is 611 nm (nanometers). This parameter defines the dominant color point of the emitted light.
• Dominant Wavelength (\u03bb_d): This is 605 nm, which is the single-wavelength perception of the color that most closely matches the actual color output of the LED. It is slightly different from the peak wavelength due to the shape of the human eye's spectral sensitivity curve.
• Spectral Line Half-Width (\u0394\u03bb): This is 17 nm, indicating the spectral purity of the light. A narrower half-width means a more saturated, pure color. This value is typical for AlInGaP technology and contributes to the distinct yellow-orange hue.
• Luminous Intensity Matching Ratio: Specified as 2:1 maximum for similar light areas. This means the brightness difference between any two segments of the same digit should not exceed a factor of two, ensuring uniform appearance across the display.

2.2 Electrical Parameters

The electrical characteristics define the operating limits and conditions for reliable use.

• Forward Voltage per Segment (V_F): Typically 2.6V at I_F=20mA, with a maximum of 2.6V. This is the voltage drop across an LED segment when it is conducting current. Designers must ensure the driving circuit can provide sufficient voltage to overcome this drop.
• Continuous Forward Current per Segment (I_F): The maximum recommended DC current for continuous operation is 25 mA. Exceeding this value can lead to accelerated degradation and reduced lifespan.
• Peak Forward Current per Segment: A higher current of 90 mA is allowed under pulsed conditions (1/10 duty cycle, 0.1ms pulse width). This is useful for multiplexing schemes where higher instantaneous brightness is needed.
• Reverse Voltage (V_R): The maximum allowable reverse-bias voltage is 5V. Exceeding this can cause immediate and catastrophic failure of the LED junction.
• Reverse Current (I_R): Typically less than 100 \u00b5A at the maximum reverse voltage of 5V, indicating good junction quality.
• Power Dissipation per Segment: Limited to 70 mW. This is calculated as V_F * I_F. Operating within this limit is crucial for thermal management.

2.3 Thermal and Environmental Ratings

• Operating Temperature Range: -35\u00b0C to +105\u00b0C. This wide range makes the display suitable for harsh environments, from freezing cold to hot industrial settings.
• Storage Temperature Range: -35\u00b0C to +105\u00b0C.
• Current Derating: The continuous forward current must be linearly derated from 25 mA at 25\u00b0C. This means as the ambient temperature rises above 25\u00b0C, the maximum allowable continuous current must be reduced to prevent overheating. The derating factor is 0.28 mA/\u00b0C.

3. Binning System Explanation

While the provided datasheet does not explicitly detail a multi-level binning system for parameters like wavelength or intensity, it does specify tight ranges for key optical characteristics. The typical values for peak wavelength (611 nm) and dominant wavelength (605 nm) suggest a controlled manufacturing process. The luminous intensity has a defined minimum (800 \u00b5cd) and typical (2222 \u00b5cd) value, indicating that devices are screened to meet the minimum performance threshold. For applications requiring tighter color or brightness matching, users should consult the manufacturer for specific binning options or select devices from the same production lot.

4. Performance Curve Analysis

The datasheet references typical characteristic curves, which are essential for understanding device behavior under non-standard conditions. Although the specific graphs are not provided in the text, standard LED curves would typically include:

• I-V (Current-Voltage) Curve: Shows the relationship between forward voltage and forward current. It is non-linear, with a sharp increase in current once the forward voltage exceeds the junction's threshold (around 2V for AlInGaP).
• 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 thermal and efficiency droop.
• Luminous Intensity vs. Ambient Temperature: For AlInGaP LEDs, light output generally decreases as temperature increases. This curve is critical for designing systems that operate over the full temperature range.
• Spectral Distribution: A plot of relative intensity versus wavelength, showing a peak around 611 nm with a characteristic width (\u0394\u03bb) of 17 nm.

Designers should use these curves to determine appropriate drive currents for desired brightness at different temperatures and to understand the voltage requirements of the driving circuit.

5. Mechanical and Package Information

The device is a through-hole component with a standard 12-pin dual-in-line package.

• Digit Height: 0.56 inches (14.22 mm). This defines the physical size of each numeric character.
• Package Dimensions: All dimensions are provided in millimeters. The general tolerance for mechanical dimensions is \u00b10.25 mm unless otherwise specified. A specific note mentions a pin tip shift tolerance of +0.4 mm, which is important for PCB hole placement and wave soldering processes.
• Polarity Identification: The device uses a common anode configuration. The internal circuit diagram (referenced but not shown) would detail how the anodes of all segments for each digit are connected together internally, and how the cathodes for individual segments are brought out to separate pins. This configuration is common for multiplexed drives.
• Pin Connection: The pinout is clearly defined: Pins 6, 8, 9, and 12 are the common anodes for digits 4, 3, 2, and 1, respectively. The remaining pins are cathodes for specific segments (A-G and DP) of digit 1. For a complete quad-digit display, the segment cathodes are likely internally connected across digits (e.g., all 'A' segments share a cathode pin), a detail that would be confirmed in the internal circuit diagram.

6. Soldering and Assembly Guidelines

The datasheet provides specific soldering conditions to prevent damage during assembly.

• Wave or Hand Soldering: The recommended condition is to solder at 260\u00b0C for a maximum of 3 seconds, with the soldering iron tip positioned at least 1/16 inch (approximately 1.6 mm) below the seating plane of the package body. This prevents excessive heat from traveling up the leads and damaging the internal LED chips and wire bonds.
• General Precaution: The temperature of the LED unit itself during the assembly process must not exceed its maximum temperature rating (105\u00b0C operating, presumably similar for short-term exposure during soldering).
• Storage Conditions: Devices should be stored within the specified storage temperature range (-35\u00b0C to +105\u00b0C) in a dry environment. Moisture-sensitive devices should be kept in sealed bags with desiccant until use.

7. Packaging and Ordering Information

The primary device part number is LTC-5653KF. This number encodes key attributes: likely the series (LTC), size/type (5653), and color/feature (KF for Yellow Orange with right-hand decimal). The datasheet does not specify bulk packaging details (e.g., tube, tray, or reel quantities). For production, users must contact the supplier for specific packaging options, reel sizes, and tape specifications compatible with automated placement equipment.

8. Application Suggestions

8.1 Typical Application Scenarios

• Industrial Timers and Counters: For displaying process times, production counts, or machine operating hours.
• Test and Measurement Equipment: Digital multimeters, frequency counters, power supplies, and sensor readouts.
• Consumer Appliances: Microwave ovens, washing machines, audio amplifiers (for volume level or station frequency).
• Automotive Aftermarket Displays: Gauges for voltage, temperature, or RPM in custom installations.

8.2 Design Considerations

• Drive Circuitry: Due to the common anode configuration, a suitable driver IC (like a 7-segment decoder/driver or a microcontroller with sufficient current-sourcing capability) is required. The anodes are switched to Vcc, while the cathodes are pulled low to turn on a segment.
• Current Limiting: External current-limiting resistors are mandatory for each cathode line (or potentially for each common anode in a multiplexed setup) to set the forward current to a safe value (e.g., 10-20 mA). The resistor value is calculated as R = (V_supply - V_F) / I_F.
• Multiplexing: For a 4-digit display, multiplexing is almost always used to minimize pin count on the controller. This involves rapidly cycling power to each digit's common anode while presenting the segment data for that digit on the common cathode lines. The persistence of vision creates the illusion of all digits being on simultaneously. The peak current rating (90 mA) allows for higher instantaneous current during the short multiplexing pulse to achieve average brightness.
• Viewing Angle: The wide viewing angle is beneficial for applications where the display may be viewed from the side.

9. Technical Comparison

The LTC-5653KF's primary differentiation lies in its AlInGaP technology and specific mechanical form factor.

• vs. Standard GaP or GaAsP LEDs: AlInGaP offers significantly higher luminous efficiency and better color saturation in the red-orange-yellow spectrum, resulting in brighter displays with lower power consumption for the same perceived brightness.
• vs. SMD (Surface Mount Device) Displays: This is a through-hole component. Compared to SMD seven-segment displays, it is easier to prototype with and may be perceived as more robust for certain applications, but it requires more PCB space and manual or wave soldering.
• vs. Other Colors: The Yellow Orange color (605-611 nm) offers a distinct aesthetic and can be easier on the eyes in low-light conditions compared to bright red or green displays, while still maintaining high visibility.

10. Frequently Asked Questions (Based on Technical Parameters)

• Q: What is the purpose of the "gray face and white segments" mentioned in the description?
  A: This is a cosmetic filter. The gray face reduces the reflectivity of the inactive display area, improving contrast. The white segment markings help diffuse the emitted yellow-orange light evenly across the segment when lit, creating a uniform appearance.
• Q: Can I drive this display directly from a 5V microcontroller pin?
  A: No, not directly. The forward voltage is about 2.6V, so a 5V signal could burn out the LED due to excessive current. You must use a current-limiting resistor in series with each cathode. Furthermore, a microcontroller pin typically cannot source or sink enough current for multiple segments. A driver IC or transistor array is usually required.
• Q: The absolute max continuous current is 25mA, but the test condition for V_F uses 20mA. Which should I use for design?
  A: For reliable long-term operation, it is standard practice to design for a current below the absolute maximum. Using 20mA as specified in the test condition is a safe and common design point. You can use lower currents (e.g., 10-15 mA) to increase lifespan and reduce power consumption if the brightness is sufficient.
• Q: What does "Common Anode" mean for my circuit design?
  A: In a common anode display, all the anodes of the LEDs in a digit are connected together to a single pin. To light a segment, you connect its cathode pin to a low voltage (ground) while applying a high voltage (Vcc) to the common anode pin. This is the opposite of a common cathode display.

11. Practical Use Case

Designing a Simple 4-Digit Voltmeter Readout: A microcontroller with an analog-to-digital converter (ADC) measures a voltage. The firmware converts this value to four digits to be displayed. The microcontroller, lacking enough I/O pins to drive 28 individual segments (7 segments x 4 digits), uses a multiplexing scheme with a driver IC. The driver IC's outputs connect to the segment cathodes (A-G, DP) of the LTC-5653KF. Four of the microcontroller's I/O pins, each connected through a current-sourcing transistor, control the four common anode pins (Digits 1-4). The firmware rapidly sequences through the digits: it turns on the transistor for Digit 1's anode, sends the segment pattern for the first digit to the driver IC, waits a short time (e.g., 2ms), then turns off Digit 1 and repeats for Digit 2, and so on. The current-limiting resistors are placed on the cathode lines between the driver IC and the display. The yellow-orange color provides clear visibility on the instrument panel.

12. Principle Introduction

A seven-segment display is an assembly of light-emitting diodes (LEDs) arranged in a figure-eight pattern. Each of the seven segments (labeled A through G) is an individual LED. An additional LED is often included for a decimal point (DP). By selectively illuminating specific combinations of these segments, all numeric digits (0-9) and some letters can be formed. In a quad-digit display like the LTC-5653KF, four such digit assemblies are housed in a single package. The internal electrical connection can be either common anode (all anodes connected) or common cathode (all cathodes connected), which determines the required driving circuit topology. The light emission principle is electroluminescence in a semiconductor p-n junction. When forward-biased, electrons and holes recombine in the active region (the AlInGaP layer), releasing energy in the form of photons. The specific material composition (Al, In, Ga, P) determines the bandgap energy and thus the wavelength (color) of the emitted light.

13. Development Trends

The evolution of numeric displays like the LTC-5653KF is influenced by broader trends in optoelectronics. While through-hole, discrete seven-segment modules remain relevant for specific applications requiring robustness or ease of servicing, the general trend is towards surface-mount technology (SMT) for higher density and automated assembly. Furthermore, there is a gradual shift from discrete LED segment displays to integrated dot-matrix displays or even small OLED or TFT-LCD panels, which offer far greater flexibility in displaying numbers, letters, symbols, and simple graphics. However, for applications demanding extreme brightness, long lifespan, simplicity, and low cost for purely numeric output, AlInGaP-based LED displays like this one continue to be a highly effective and reliable solution. Future iterations may see improvements in efficiency, allowing even lower power consumption, or the integration of driver electronics within the display package itself.