ELD-526SURWA/S530-A3 Seven Segment Display Datasheet - 13.6mm Digit Height - 2.4V Forward Voltage - Brilliant Red - English Technical Document

1. Product Overview

The ELD-526SURWA/S530-A3 is a single-digit, seven-segment alphanumeric display designed for through-hole mounting. It features a standard industrial size with a digit height of 13.6 millimeters (0.54 inches). The device is constructed with brilliant red AlGaInP LED chips, housed within a white diffusion resin package that presents a gray surface appearance. This combination is engineered to deliver high reliability and excellent readability even in environments with bright ambient light. The display is categorized based on luminous intensity and is compliant with Pb-free and RoHS environmental standards, making it suitable for modern electronic assembly processes.

1.1 Core Advantages and Target Market

The primary advantages of this display include its low power consumption, standardized footprint for easy replacement or integration, and robust performance in various lighting conditions. Its design prioritizes longevity and consistent output. The target applications are diverse, focusing primarily on consumer and industrial electronics where clear numeric readouts are essential. Key markets include home appliance control panels (e.g., ovens, washing machines), instrumentation for measurement devices, and general-purpose digital readout displays in various equipment.

2. Technical Parameters: In-Depth Objective Interpretation

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

2.1 Absolute Maximum Ratings

The Absolute Maximum Ratings define the stress limits beyond which permanent damage to the device may occur. These are not conditions for normal operation.

• Reverse Voltage (V_R): 5 V. Exceeding this voltage in reverse bias can cause immediate junction breakdown.
• Forward Current (I_F): 25 mA (Continuous). The maximum DC current that can be applied continuously.
• Peak Forward Current (I_FP): 60 mA. This is the maximum allowable pulsed current, specified at a duty cycle of 1/10 and a frequency of 1 kHz. It is crucial for multiplexing applications.
• Power Dissipation (P_d): 60 mW. The maximum power the device can dissipate as heat, calculated as Forward Voltage (V_F) multiplied by Forward Current (I_F).
• Operating Temperature (T_opr): -40°C to +85°C. The ambient temperature range over which the device is guaranteed to meet its published specifications.
• Storage Temperature (T_stg): -40°C to +100°C.
• Soldering Temperature (T_sol): 260°C for a duration not exceeding 5 seconds. This is critical for wave or hand soldering processes.

2.2 Electro-Optical Characteristics

These parameters are measured under standard test conditions (Ta=25°C) and represent the typical performance of the device.

• Luminous Intensity (I_v): The typical value is 12.5 mcd per segment when driven at 10 mA. The minimum specified is 7.8 mcd. The datasheet notes a tolerance of ±10% on luminous intensity, which is part of the categorization (binning) process. The measurement is an average across one seven-segment digit.
• Peak Wavelength (λ_p): 632 nm (typical). This is the wavelength at which the spectral emission is strongest.
• Dominant Wavelength (λ_d): 624 nm (typical). This is the wavelength perceived by the human eye and defines the color (brilliant red).
• Spectral Bandwidth (Δλ): 20 nm (typical). This indicates the range of wavelengths emitted, centered around the peak wavelength.
• Forward Voltage (V_F): 2.0 V (typical), with a maximum of 2.4 V at 20 mA. The tolerance is ±0.1V. This parameter is vital for designing the current-limiting circuitry.
• Reverse Current (I_R): Maximum 100 µA at a reverse voltage of 5V.

3. Binning System Explanation

The datasheet indicates that the devices are \"Categorized for luminous intensity.\" This refers to a binning or sorting process.

• Luminous Intensity Binning: The LEDs are tested and sorted into groups (bins) based on their measured luminous intensity at the standard test current. The specified tolerance of ±10% defines the range for a given bin. Designers should be aware that brightness can vary within this range from one production lot to another, which may be noticeable if multiple displays are used side-by-side in a product.
• Forward Voltage Binning: While not explicitly stated as a binned parameter, the ±0.1V tolerance on V_F indicates tight control. Significant variation in forward voltage across multiple segments or digits could lead to uneven current distribution if driven in a simple parallel configuration without individual current limiting.
• Wavelength/Color Binning: The datasheet specifies typical values for peak and dominant wavelength but does not mention explicit color bins. For a standard brilliant red display, the typical 624 nm dominant wavelength is the target.

4. Performance Curve Analysis

The datasheet includes typical characteristic curves which provide insight into device behavior under non-standard conditions.

4.1 Spectrum Distribution

The spectral distribution curve (relative intensity vs. wavelength) would show a narrow peak centered around 632 nm (peak) with a dominant wavelength at 624 nm. The 20 nm bandwidth indicates a relatively pure red color, which is characteristic of AlGaInP semiconductor material. This material is known for its high efficiency in the red to amber color range.

4.2 Forward Current vs. Forward Voltage (I-V Curve)

This curve illustrates the non-linear relationship between current and voltage. For a typical LED, the curve shows a very low current until the forward voltage reaches a \"knee\" point (around 1.8-2.0V for this device), after which current increases rapidly with a small increase in voltage. This underscores the importance of driving LEDs with a constant current source rather than a constant voltage source to prevent thermal runaway and ensure consistent brightness.

4.3 Forward Current Derating Curve

This is a critical graph for thermal management. It shows the maximum allowable continuous forward current as a function of the ambient temperature. As the ambient temperature increases, the device's ability to dissipate heat decreases. Therefore, the maximum safe operating current must be reduced (derated) to prevent exceeding the junction temperature limit and ensure long-term reliability. The curve typically starts at the rated current (e.g., 25 mA) at 25°C and slopes downward to zero current at the maximum junction temperature.

5. Mechanical and Package Information

5.1 Dimensions and Drawing

The package dimension drawing provides the exact physical measurements for PCB layout. Key dimensions include the overall height, width, and depth of the display, the spacing between pins (pitch), the pin diameter, and the recommended PCB hole size. The drawing includes a note that tolerances are ±0.25mm unless otherwise specified. Engineers must adhere to these dimensions to ensure proper fit and alignment on the printed circuit board.

5.2 Pinout and Polarity Identification

The internal circuit diagram shows the common-anode configuration of the seven segments and the decimal point (if present). It identifies the pin numbers corresponding to each segment (a through g) and the common anode pin(s). Correct polarity identification is essential; applying reverse voltage or incorrect common connection will prevent the display from illuminating or could damage it.

6. Soldering and Assembly Guidelines

• Soldering Process: The device is suitable for wave soldering or hand soldering. The absolute maximum rating for soldering temperature is 260°C for a maximum duration of 5 seconds. This is a standard rating for through-hole components and helps prevent thermal damage to the LED chip and the plastic package.
• Electrostatic Discharge (ESD) Protection: The datasheet contains a strong warning about ESD sensitivity. AlGaInP LEDs can be damaged by electrostatic discharge. Recommended handling precautions include the use of grounded wrist straps, ESD-safe workstations and flooring, conductive table mats, and proper grounding of all equipment. If insulating materials are present, ionizers or other charge-neutralizing methods should be employed.
• Storage Conditions: Devices should be stored within the specified storage temperature range (-40°C to +100°C) in a low-humidity, ESD-protected environment.

7. Packaging and Ordering Information

7.1 Packaging Specification

The device is packaged in tubes for automated assembly. The standard packing process is: 20 pieces per tube, 36 tubes per box, and 4 boxes per master carton. This totals 2,880 pieces per carton.

7.2 Label Explanation

The packing label includes several codes: Customer's Product Number (CPN), Manufacturer's Product Number (P/N), Packing Quantity (QTY), Luminous Intensity Rank (CAT), and Lot Number (LOT No.). The \"CAT\" field directly corresponds to the luminous intensity bin discussed earlier.

8. Application Design Suggestions

8.1 Typical Application Circuits

As a common-anode display, the anodes (common pins) are typically connected to a positive supply voltage through a current-limiting resistor or a transistor switch (for multiplexing). The cathode of each segment is then connected to a driver IC (like a 7-segment decoder/driver or a microcontroller GPIO pin) capable of sinking the required current. A series current-limiting resistor is mandatory for each segment or common anode to set the forward current to the desired value (e.g., 10-20 mA). The resistor value is calculated using Ohm's Law: R = (V_supply - V_F) / I_F.

8.2 Design Considerations and Warnings

• Current Limiting: Always use a constant current drive or a current-limiting resistor. Never connect the LED directly to a voltage source.
• Reverse Voltage Protection: The driving circuit must ensure that no reverse voltage is applied to the LED, even when off. Continuous reverse voltage can cause metal migration and permanent damage. In AC or multiplexed circuits, consider adding a protection diode in parallel with the LED (reverse-biased during normal operation).
• Thermal Management: For high ambient temperature applications or when driving near the maximum current, consider the derating curve. Ensure adequate spacing on the PCB for heat dissipation.
• Multiplexing: This display is suitable for multiplexed applications where multiple digits share driver lines. The peak forward current rating (60 mA at 1/10 duty cycle) supports this. The average current per segment must not exceed the continuous forward current rating (25 mA).

9. Technical Comparison and Differentiation

Compared to older technologies or smaller displays, the ELD-526SURWA/S530-A3 offers specific advantages:

• Material (AlGaInP vs. GaAsP): AlGaInP technology provides higher luminous efficiency and a more saturated, brilliant red color compared to older GaAsP LEDs, which often appear more orange or dim.
• Standardized Size: The 13.6mm digit height is an industrial standard, ensuring wide compatibility with existing product designs and bezels.
• Low Power Consumption: With a typical forward voltage of 2.0V, it operates efficiently, reducing power supply requirements and heat generation compared to displays with higher V_F.
• Gray Surface: The gray surface (vs. black) provides better contrast in brightly lit environments by reducing reflected ambient light, enhancing readability.

10. Frequently Asked Questions (Based on Technical Parameters)

Q: Can I drive this display with 5V logic from a microcontroller?
A: Yes, but you must use a current-limiting resistor. For example, to achieve ~10 mA with a 5V supply: R = (5V - 2.0V) / 0.01A = 300 Ohms. A 330 Ohm resistor is a standard value that would provide slightly less current, which is safe.

Q: Why is there a minimum luminous intensity specified (7.8 mcd) and a typical (12.5 mcd)?
A: The minimum is the guaranteed lower limit for devices sold under this part number. The typical is the average output from production. Due to the binning process (±10%), you may receive devices whose brightness is anywhere within that categorized range.

Q: Is this display suitable for outdoor use?
A: The operating temperature range (-40°C to +85°C) suggests it can handle a wide range of environments. However, for direct outdoor exposure, consider additional factors not covered in the datasheet, such as UV resistance of the plastic, waterproofing, and conformal coating for the PCB.

Q: What happens if I exceed the 5V reverse voltage?
A: Exceeding the reverse voltage rating can cause immediate and catastrophic failure of the LED junction due to avalanche breakdown. The device is not designed to withstand reverse bias.

11. Practical Design and Usage Case

Case: Designing a Simple Digital Voltmeter Readout.
A designer is creating a benchtop power supply unit that requires a 3-digit voltage display. They select three ELD-526SURWA/S530-A3 displays. The microcontroller (e.g., an ATmega328) will use a 7-segment driver IC like the MAX7219. The design steps include: 1) Laying out the PCB according to the package dimensions, ensuring correct pin spacing. 2) Connecting the common anodes of each digit to the driver IC's digit select lines. 3) Connecting the segment cathodes (a-g) to the driver IC's segment lines. 4) Programming the microcontroller to read an ADC value, convert it to voltage, and send the appropriate digit codes to the MAX7219 via SPI. 5) Setting the drive current within the MAX7219's registers to target 10-15 mA per segment, ensuring it stays within the display's ratings. The gray surface of the display is chosen specifically because the lab environment has overhead fluorescent lighting.

12. Operating Principle Introduction

A seven-segment LED display is an assembly of individual Light Emitting Diodes (LEDs) arranged in the pattern of the digit \"8\". Each segment (named a through g) is a separate LED. By selectively turning on specific segments, any numeral from 0 to 9 and some letters can be formed. The ELD-526SURWA/S530-A3 uses a common-anode configuration, meaning the anodes (positive terminals) of all segment LEDs in one digit are connected together to a common pin(s). To illuminate a segment, its common anode is connected to a voltage source (through a current limiter), and its cathode (negative terminal) is connected to a lower voltage (ground). The light is produced through electroluminescence in the AlGaInP semiconductor material: when a forward voltage is applied, electrons and holes recombine in the active region, releasing energy in the form of photons (light) at a wavelength corresponding to the material's bandgap, which is in the red spectrum.

13. Technology Trends and Context

Seven-segment LED displays represent a mature and reliable technology. While newer display technologies like dot-matrix OLEDs or TFT LCDs offer greater flexibility for graphics and custom fonts, 7-segment LEDs retain strong advantages in specific applications: superior brightness and sunlight readability, extremely wide viewing angles, high reliability and long lifetime, simplicity of control, and lower cost for applications that only require numeric output. The trend in such discrete LED displays is towards higher efficiency (more light output per mA of current), tighter binning for color and brightness consistency, and continued compliance with evolving environmental regulations (RoHS, REACH). The through-hole package, as used in this datasheet, is gradually being supplemented by surface-mount device (SMD) versions for automated assembly, but through-hole remains vital for prototyping, repair, and applications requiring higher mechanical robustness.