LTD-4830CKR-P LED Display Datasheet - 0.39-inch Digit Height - Super Red - 2.6V Forward Voltage - English Technical Document

1. Product Overview

The product is a surface-mount device (SMD) featuring a dual-digit, seven-segment LED display. The primary application is for numeric readouts in electronic equipment where clear visibility and reliability are required.

1.1 Core Features and Target Market

This display is characterized by a 0.39-inch (10.0 mm) digit height, providing good readability. It utilizes AlInGaP (Aluminum Indium Gallium Phosphide) semiconductor technology on a GaAs substrate to produce a \"Super Red\" emission. The package features a gray face with white segments, enhancing contrast. Key advantages include low power consumption, high brightness, a wide viewing angle, and solid-state reliability. It is categorized for luminous intensity and is compliant with lead-free (RoHS) requirements. Its typical applications include consumer electronics, instrumentation panels, and industrial control interfaces where space-saving SMD components are preferred.

1.2 Device Identification

The specific part number is LTD-4830CKR-P. This identifier signifies a common anode configuration with a right-hand decimal point. The \"Super Red\" refers to the specific color and material technology of the LED chips used.

2. Technical Parameters: In-Depth Objective Interpretation

2.1 Absolute Maximum Ratings

These parameters define the limits beyond which permanent damage to the device may occur. The maximum power dissipation per segment is 70 mW. The peak forward current per segment is 90 mA, but this is only permissible under pulsed conditions (1/10 duty cycle, 0.1ms pulse width). The continuous forward current per segment is rated at 25 mA at 25°C, with a derating factor of 0.28 mA/°C, meaning the allowable continuous current decreases as ambient temperature rises. The device is rated for operation and storage within a temperature range of -35°C to +105°C. The iron soldering condition is specified as a one-time process of 3 seconds at 300°C.

2.2 Electrical and Optical Characteristics

These are the typical operating parameters measured at 25°C. The luminous intensity (Iv) is highly current-dependent: typically 501-1700 µcd at 1 mA and 22100 µcd at 10 mA per segment. The peak emission wavelength (λp) is 639 nm, and the dominant wavelength (λd) is 631 nm, placing the output in the red region of the spectrum. The spectral line half-width (Δλ) is 20 nm. The forward voltage (Vf) per chip is typically 2.6V at a test current of 20 mA. The reverse current (Ir) is a maximum of 100 µA at a reverse voltage (Vr) of 5V, but it is crucial to note that this is a test condition; the device is not designed for continuous reverse bias operation. Luminous intensity matching between segments is specified with a maximum ratio of 2:1 under similar driving conditions to ensure uniform appearance. Cross-talk between segments is limited to ≤ 2.5%.

2.3 Binning System Explanation

The luminous output of LEDs naturally varies in production. To ensure consistency for the end-user, devices are sorted into bins based on their measured luminous intensity at a standard drive current of 1 mA. The bin table provided lists five categories (G, H, J, K, L) with defined minimum and maximum intensity ranges in microcandelas (µcd), each with a +/-15% tolerance. For example, Bin G covers 501-800 µcd, while Bin L covers 3401-5400 µcd. This allows designers to select a brightness grade suitable for their application's requirements.

3. Performance Curve Analysis

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

• IV Curve (Current vs. Voltage): Shows the relationship between forward current and forward voltage, which is non-linear. This is critical for designing the current-limiting circuitry.
• Luminous Intensity vs. Forward Current: Demonstrates how light output increases with drive current, helping to optimize for brightness and efficiency.
• Temperature Characteristics: Would show how forward voltage and luminous intensity change with ambient or junction temperature, informing thermal management decisions.
• Spectral Distribution: A graph of relative intensity vs. wavelength, confirming the peak and dominant wavelengths and the spectral width.

Designers should consult the full datasheet graphs to make accurate predictions about performance in their specific operating environment.

4. Mechanical and Package Information

4.1 Package Dimensions

The device comes in a standard SMD package. All critical dimensions are provided in millimeters with a general tolerance of ±0.25 mm unless otherwise specified. The drawing includes overall length, width, and height, lead spacing, and the position of the decimal point. Additional quality notes specify limits for foreign material on segments (≤10 mil), surface ink contamination (≥20 mils), bubbles in segments (≤10 mil), bending of the reflector (≤1% of length), and plastic pin burr (max 0.1 mm).

4.2 Internal Circuit Diagram and Pin Connection

The internal circuit diagram shows the common anode configuration for two digits. Each digit's anode is common, while each segment (A-G and DP) has its own cathode pin. The pin connection table clearly maps the 20-pin package. For example, pins 3 and 18 are the common anodes for Digit 1, while pins 8 and 13 are for Digit 2. Cathodes for specific segments (e.g., A1, B1, DP1) are assigned to other pins. This information is vital for creating the correct PCB footprint and designing the driver circuit.

4.3 Recommended Soldering Pad Pattern

A land pattern design is provided to ensure reliable solder joints during reflow soldering. Adhering to this recommended pattern helps prevent tombstoning, insufficient solder, or bridging.

5. Soldering and Assembly Guidelines

5.1 SMT Soldering Instruction

The device is designed for reflow soldering. The recommended profile includes a pre-heat stage of 120-150°C for a maximum of 120 seconds, followed by a peak temperature not exceeding 260°C. The total number of reflow process cycles must be less than two. If a second pass is required, the assembly must be allowed to cool to normal temperature between cycles. For manual repair, soldering with an iron is limited to one time only, at a maximum temperature of 300°C for no more than 3 seconds. These limits are in place to prevent thermal damage to the plastic package and the internal wire bonds.

5.2 Moisture Sensitivity and Storage

The SMD package is moisture-sensitive. It is shipped in a moisture-proof bag with a Moisture Sensitivity Level (MSL) of 3. This means the device must be used within 168 hours (1 week) of the bag being opened when stored at factory conditions (≤30°C/60% RH). If exposed beyond this or not stored in dry conditions, the parts must be baked before reflow to drive out absorbed moisture and prevent \"popcorning\" damage during soldering. Baking conditions are specified: 60°C for ≥48 hours if on reel, or 100°C for ≥4 hours / 125°C for ≥2 hours if in bulk.

6. Packaging and Ordering Information

6.1 Packing Specification

The devices are supplied on 13-inch embossed carrier tapes wound onto reels. Each reel contains 550 pieces. A minimum packing quantity of 200 pieces is specified for remainder lots. Detailed dimensions for the packing reel, the carrier tape pocket that holds the device, and the leader/trailer tape are provided to ensure compatibility with automated pick-and-place equipment.

7. Application Notes and Design Considerations

7.1 Application Suggestions

This display is intended for ordinary electronic equipment such as office equipment, communication devices, and household appliances. For applications requiring exceptional reliability where failure could jeopardize safety (e.g., aviation, medical systems), consultation is required. The driving circuit must be designed to comply with the absolute maximum ratings. Key design considerations include:

• Current Control: LEDs are current-driven devices. A constant current driver or appropriate current-limiting resistors are mandatory to prevent exceeding the maximum continuous current, which causes severe light degradation or failure.
• Thermal Management: Operating at temperatures above the recommended range accelerates aging. Ensure adequate PCB layout and ventilation, especially when driving at higher currents.
• Electrical Protection: The circuit should incorporate protection against reverse voltages and transient voltage spikes during power-up/down sequences, as the LEDs have a low reverse breakdown voltage.
• Bin Selection: Choose the appropriate luminous intensity bin (G through L) based on the required brightness and viewing conditions of the end application.

7.2 Common Questions Based on Technical Parameters

Q: What driver current should I use?
A: The current depends on the required brightness. Refer to the Iv vs. If curve. A typical operating point is between 5-20 mA per segment. Always use a constant current source or a series resistor calculated using (Supply Voltage - Total Vf of series LEDs) / Desired Current.

Q: Can I multiplex these digits?
A: Yes, the common anode configuration is ideal for multiplexing. By sequentially enabling the common anode of each digit and presenting the cathode data for that digit, you can control multiple digits with fewer I/O pins. Ensure the peak current in multiplexed operation does not exceed the absolute maximum ratings.

Q: How do I interpret the 2:1 intensity matching ratio?
A: This means that within a single device, the dimmest segment will be no less than half as bright as the brightest segment when driven under identical conditions. This ensures visual uniformity.

8. Operational Principle and Technology Trends

8.1 Principle of Operation

The device operates on the principle of electroluminescence in a semiconductor p-n junction. When a forward voltage exceeding the diode's threshold is applied, electrons and holes recombine in the active region (the AlInGaP epitaxial layer). This recombination releases energy in the form of photons, producing light. The specific composition of the AlInGaP alloy determines the bandgap energy and thus the wavelength (color) of the emitted light, in this case, red. Each segment of the digit is a separate set of these LED chips connected in a pattern.

8.2 Technology Context and Trends

AlInGaP technology is mature for producing high-efficiency red, orange, and yellow LEDs. Compared to older technologies, it offers higher brightness and better temperature stability. The trend in display components like this is towards higher pixel density (smaller segments or dot matrix), lower power consumption, improved contrast ratios, and integration of driver electronics. Surface-mount technology (SMT) remains dominant for automated assembly. The move towards lead-free and halogen-free materials in compliance with environmental regulations is also a standard industry practice.