LTS-10804JD-02J LED Display Datasheet - 1.0 Inch Digit Height - Hyper Red (650nm) - 25mA Forward Current - English Technical Document

1. Product Overview

The LTS-10804JD-02J is a single-digit, seven-segment alphanumeric display designed for applications requiring clear, high-visibility numeric readouts. Its primary function is to convert electrical signals into visible numeric characters (0-9) and some letters. The device utilizes advanced Aluminium Indium Gallium Phosphide (AlInGaP) semiconductor technology grown on a Gallium Arsenide (GaAs) substrate to produce its characteristic Hyper Red emission. This technology offers advantages in efficiency and luminous intensity compared to older LED materials. The display features a gray faceplate with white segment diffusers, providing high contrast for optimal readability under various lighting conditions. It is categorized as a low-current device, making it suitable for battery-powered or power-sensitive applications where minimizing energy consumption is critical.

1.1 Core Features and Advantages

The display incorporates several key features that define its performance and application scope:

• 1.0 Inch (25.4 mm) Digit Height: This large character size ensures excellent visibility from a distance, making it ideal for panel meters, instrumentation, and industrial control displays.
• Continuous Uniform Segments: The segments are designed to emit light evenly across their entire surface, eliminating hot spots and creating a professional, consistent appearance.
• Low Power Requirement: Operating at a typical forward current of 20mA per segment, it consumes minimal power, extending battery life in portable devices.
• High Brightness & High Contrast: The combination of bright AlInGaP LEDs and a gray face/white segment design delivers superior luminance and contrast ratios, ensuring legibility in both dim and brightly lit environments.
• Wide Viewing Angle: The optical design allows for clear character recognition from a broad range of angles, enhancing usability.
• Categorized for Luminous Intensity: Units are binned or tested to ensure consistent light output levels, which is crucial for applications using multiple displays where uniformity is required.
• Lead-Free Package (RoHS Compliant): The construction complies with the Restriction of Hazardous Substances directive, making it suitable for use in products sold in markets with strict environmental regulations.

1.2 Device Identification and Configuration

The part number LTS-10804JD-02J provides specific information about the device. It denotes a Common Anode configuration, meaning the anodes of all LED segments are connected internally and brought out to common pins. This configuration simplifies multiplexing in multi-digit displays. The \"Rt. Hand Decimal\" indicates the inclusion of a right-hand decimal point (DP) segment. The use of AlInGaP Hyper Red chips results in a dominant wavelength of approximately 639nm, which is in the deep red portion of the visible spectrum.

2. Technical Parameters: In-Depth Objective Interpretation

This section provides a detailed, objective analysis of the device's electrical and optical characteristics as defined in the datasheet.

2.1 Absolute Maximum Ratings

These ratings define the stress limits beyond which permanent damage to the device may occur. They are not intended for normal operation.

• Power Dissipation per Segment: 70 mW. Exceeding this limit can cause overheating and accelerated degradation of the LED chip.
• Peak Forward Current per Segment: 90 mA, but only under pulsed conditions (1/10 duty cycle, 0.1ms pulse width). This rating is relevant for brief, high-intensity flashing applications.
• Continuous Forward Current per Segment: 25 mA at 25°C. This current derates linearly at 0.33 mA/°C as ambient temperature (Ta) increases above 25°C. For example, at 85°C, the maximum allowable continuous current would be approximately: 25 mA - [0.33 mA/°C * (85°C - 25°C)] = 5.2 mA.
• Reverse Voltage per Segment: 5 V. Applying a reverse bias voltage higher than this can cause junction breakdown.
• Operating & Storage Temperature Range: -35°C to +105°C. The device can withstand these extreme temperatures without permanent damage, although performance at temperature extremes will be outside the specified typical parameters.

2.2 Electrical & Optical Characteristics (Ta=25°C)

These parameters define the device's performance under normal operating conditions.

• Average Luminous Intensity (Iv): 2000-3300 ucd (microcandelas) at IF=1mA. This is a measure of the perceived brightness by the human eye. The wide range indicates a typical spread; for precise matching, consult binning information.
• Peak Emission Wavelength (λp): 650 nm. This is the wavelength at which the spectral power output is highest.
• Dominant Wavelength (λd): 639 nm. This is the single wavelength perceived by the human eye that best matches the color of the emitted light, which is a deep, saturated red.
• Spectral Line Half-Width (Δλ): 20 nm. This indicates the spectral purity; a narrower width means a more monochromatic (pure color) output.
• Forward Voltage per Chip (VF): 2.10V to 2.60V at IF=20mA. This is the voltage drop across the LED when operating. Circuit designs must account for this range to ensure consistent current drive.
• Reverse Current per Segment (IR): Maximum 100 µA at VR=5V. This is a leakage current specification for testing purposes only; the device is not intended for continuous reverse bias operation.
• Luminous Intensity Matching Ratio: 2:1 maximum for segments in a similar light area. This means the dimmest segment will be no less than half as bright as the brightest segment under the same conditions, ensuring character uniformity.
• Cross Talk: Specification is less than 2.50%. This refers to unwanted light emission from a segment that is intended to be off, caused by electrical or optical leakage from adjacent powered segments.

3. Mechanical and Packaging Information

3.1 Package Dimensions and Tolerances

The physical outline of the display is critical for PCB layout and mechanical integration. Key dimensional notes from the datasheet include:

• All primary dimensions have a tolerance of ±0.25mm unless otherwise specified.
• Pin tip shift tolerance is ±0.4 mm, which must be considered for PCB hole placement.
• The recommended PCB hole diameter for the pins is 1.40 mm to ensure a proper fit for soldering.
• Quality control criteria are defined for visual defects: foreign material on a segment (≤10 mils), bubbles in the segment material (≤10 mils), bending of the reflector (≤1% of length), and surface ink contamination (≤20 mils).

3.2 Pin Connection and Internal Circuit

The device has a 14-pin configuration. The internal circuit diagram shows a Common Anode structure. The pinout is as follows:

• Pins 4 and 11: COMMON ANODE (CA). These are internally connected.
• Segment Cathodes: Pin 1 (E), Pin 2 (D), Pin 5 (C), Pin 6 (DP), Pin 8 (B), Pin 9 (A), Pin 12 (F), Pin 14 (G).
• No Connection (NC): Pins 3, 7, 10, 13. These pins are physically present but have no internal electrical connection.

This pinout is standard for many single-digit, common-anode displays, aiding in design portability. The two common anode pins (4 and 11) allow for more flexible PCB routing and can help balance current distribution.

4. Soldering and Assembly Guidelines

4.1 Soldering Profile and Conditions

Proper soldering is essential to prevent thermal damage. The datasheet specifies two methods:

• Auto (Wave) Soldering: The device can be subjected to solder temperature 1/16 inch (≈1.6mm) below the seating plane for a maximum of 5 seconds at 260°C. The temperature of the device body itself must not exceed its maximum temperature rating during this process.
• Manual Soldering: For hand soldering, the iron tip should be applied 1/16 inch below the seating plane for a maximum of 5 seconds at 350°C ±30°C. The shorter time at a higher temperature requires careful operator skill to avoid overheating.

The primary risk is excessive heat traveling up the lead frame and damaging the epoxy package or the internal wire bonds connecting the LED chip to the pins.

5. Reliability and Environmental Testing

The device undergoes a series of standardized tests to ensure long-term performance and durability. The test conditions reference established military (MIL-STD), Japanese industrial (JIS), and internal standards.

• Operation Life (RTOL): 1000 hours of continuous operation at maximum rated current under room temperature. Performance is checked at intervals (0, 168, 500, 800, 1000 hours) to monitor for degradation.
• Environmental Stress Tests: These include High Temperature/Humidity Storage (65°C, 90-95% RH, 500h), High Temperature Storage (105°C, 1000h), Low Temperature Storage (-35°C, 1000h), Temperature Cycling (30 cycles between -35°C and 105°C), and Thermal Shock (30 cycles between -35°C and 105°C).
• Solderability Tests: Solder Resistance (260°C for 10s) and Solderability (245°C for 5s) verify that the pins can withstand assembly processes and form proper solder joints.

These tests simulate years of field operation and harsh storage conditions, providing confidence in the component's robustness.

6. Application Suggestions and Design Considerations

6.1 Typical Application Scenarios

Due to its large digit size, high contrast, and low power consumption, the LTS-10804JD-02J is well-suited for:

• Test and Measurement Equipment: Digital multimeters, frequency counters, power supplies.
• Industrial Controls: Process variable displays (temperature, pressure, flow), timer readouts, counter displays.
• Consumer Electronics: Vintage-style clocks, audio equipment displays (e.g., amplifier output level), appliance control panels.
• Automotive Aftermarket: Gauges and readouts where high visibility is required.

6.2 Critical Design Considerations

The datasheet includes crucial cautions for the design engineer:

• Drive Current and Temperature: Exceeding the recommended continuous forward current or operating temperature will lead to accelerated light output degradation (lumen depreciation) and can cause premature failure. The derating curve for current vs. temperature must be strictly followed.
• Circuit Protection: The driving circuit must incorporate protection against reverse voltages and voltage transients that can occur during power-up or shutdown sequences. A simple series resistor is insufficient for transient protection; diodes or more complex circuits may be needed.
• Constant Current Drive: For consistent brightness and to mitigate the effects of forward voltage (VF) variation from unit to unit and with temperature, a constant current driver is strongly recommended over a simple current-limiting resistor. This ensures each segment receives the intended current regardless of VF shifts.
• Forward Voltage Range: The power supply or driver circuit must be designed to accommodate the full range of VF (2.10V to 2.60V at 20mA) to guarantee the target drive current can be delivered under all conditions. If using a voltage source with a series resistor, the supply voltage must be high enough to overcome the maximum VF plus the resistor drop.

7. Performance Curve Analysis and Technical Comparison

7.1 Interpretation of Typical Curves

While the specific graphs are not detailed in the provided text, typical datasheets for such devices include:

• Relative Luminous Intensity vs. Forward Current (I_V vs. I_F): This curve is typically linear at lower currents but may show saturation or sub-linear behavior at higher currents, emphasizing the need to operate within the specified range for efficiency.
• Forward Voltage vs. Forward Current (V_F vs. I_F): This shows the exponential relationship characteristic of a diode. The curve shifts with temperature; V_F decreases as temperature increases for a given current.
• Relative Luminous Intensity vs. Ambient Temperature (I_V vs. T_a): Light output generally decreases as ambient temperature rises. This curve is critical for applications operating in high-temperature environments.
• Spectral Distribution: A graph showing light intensity across wavelengths, centered around 650nm with a typical half-width of 20nm, confirming the Hyper Red color.

7.2 Differentiation from Other Technologies

Compared to other common seven-segment display technologies:

• vs. Standard Red GaAsP/GaP LEDs: AlInGaP offers significantly higher luminous efficiency (more light output per mA of current) and better high-temperature performance, resulting in brighter displays with lower power consumption or longer life.
• vs. LCDs: LEDs are emissive (produce their own light), making them clearly visible in darkness without a backlight. They also have a much wider viewing angle and faster response time. However, they generally consume more power than reflective LCDs.
• vs. VFDs (Vacuum Fluorescent Displays): LEDs are solid-state, more rugged, require lower operating voltages, and have a longer operational lifetime. VFDs can offer a different aesthetic (often blue-green) and very wide viewing angles.

8. Frequently Asked Questions (Based on Technical Parameters)

Q: Can I drive this display with a 5V supply and a resistor?
A: Yes, but careful calculation is needed. For a 20mA segment current and a typical V_F of 2.4V, the series resistor value would be R = (5V - 2.4V) / 0.02A = 130 Ohms. You must use the maximum V_F (2.6V) to ensure enough voltage is available to reach 20mA under worst-case conditions: R_min = (5V - 2.6V) / 0.02A = 120 Ohms. A 120-ohm resistor would provide at least 20mA. However, brightness will vary with V_F.

Q: Why are there two common anode pins (4 and 11)?
A> They are internally connected. Having two pins provides mechanical stability, allows for dual-sided PCB routing to reduce trace resistance, and helps in heat dissipation from the common anode connection, which carries the sum of the currents of all lit segments.

Q: What is the purpose of the \"No Pin\" connections?
A> They are placeholders to maintain a standard 14-pin DIP (Dual In-line Package) footprint. This allows the display to be physically compatible with sockets and PCB layouts designed for other 14-pin devices or displays with different internal configurations (e.g., common cathode).

Q: How do I control the decimal point?
A> The decimal point (DP) is simply another LED segment, controlled by its own cathode (Pin 6). To illuminate it, you would connect the common anodes (Pins 4/11) to a positive voltage and sink current from Pin 6 to ground through an appropriate current-limiting resistor or driver, just like any other segment (A-G).