ELS-322SURWA/S530-A3 7.62mm Red LED Seven-Segment Display Datasheet - 0.3" Digit Height - 2.4V Forward Voltage - 25mA Forward Current - English Technical Document

1. Product Overview

The ELS-322SURWA/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 7.62mm (0.3 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 bright ambient lighting conditions, making it suitable for a variety of indicator and readout applications.

1.1 Core Features and Advantages

• Standard Footprint: Conforms to common industrial dimensions for easy integration into existing panel designs and PCB layouts.
• Low Power Consumption: Operates efficiently with standard drive currents, contributing to energy-saving designs.
• Intensity Categorization: Devices are binned for luminous intensity, ensuring consistent brightness levels across production batches and simplifying design for uniform appearance.
• Environmental Compliance: The product is manufactured to be lead-free (Pb-free) and is compliant with the RoHS (Restriction of Hazardous Substances) directive.
• High Contrast: The white segments against a gray background provide a high-contrast display for clear visibility.

1.2 Target Applications

This display is versatile and finds use in numerous electronic devices requiring numeric or limited alphanumeric readouts. Primary application areas include:

• Home Appliances (e.g., ovens, microwaves, washing machines)
• Instrumentation Panels for industrial equipment
• Digital Readout Displays in test and measurement devices
• Consumer Electronics
• Automotive Aftermarket Accessories

2. Technical Parameter Analysis

2.1 Absolute Maximum Ratings

These ratings define the limits beyond which permanent damage to the device may occur. Operation under or at these extremes is not guaranteed.

• Reverse Voltage (V_R): 5 V - The maximum voltage that can be applied in the reverse direction across the LED.
• Continuous Forward Current (I_F): 25 mA - The maximum recommended continuous DC current for reliable long-term operation.
• Peak Forward Current (I_FP): 60 mA - The maximum allowable pulsed forward current, specified at a duty cycle of 1/10 and a frequency of 1 kHz. This is relevant for multiplexed driving schemes.
• Power Dissipation (P_d): 60 mW - The maximum power the device can dissipate.
• Operating Temperature (T_opr): -40°C to +85°C - The ambient temperature range over which the device is designed to function.
• Storage Temperature (T_stg): -40°C to +100°C.
• Soldering Temperature (T_sol): 260°C for a maximum duration of 5 seconds, which is compatible with standard wave or reflow soldering processes.

2.2 Electro-Optical Characteristics

These parameters are measured at an ambient temperature (T_a) of 25°C and define the typical performance of the device.

• Luminous Intensity (I_v): The typical value is 11.0 mcd per segment at a forward current (I_F) of 10 mA, with a minimum of 5.6 mcd. The average value is measured on a single segment. A tolerance of ±10% applies.
• Peak Wavelength (λ_p): Typically 632 nm at I_F=20mA, defining the wavelength at which the emitted light intensity is highest.
• Dominant Wavelength (λ_d): Typically 624 nm at I_F=20mA. This is the single wavelength perceived by the human eye that matches the color of the emitted light.
• Spectral Bandwidth (Δλ): Typically 20 nm at I_F=20mA, indicating the range of wavelengths emitted around the peak.
• Forward Voltage (V_F): Typically 2.0 V, with a maximum of 2.4 V at I_F=20mA. Tolerance is ±0.1V. This is a critical parameter for designing the current-limiting circuitry.
• Reverse Current (I_R): Maximum of 100 µA when a reverse voltage (V_R) of 5V is applied.

3. Performance Curve Analysis

3.1 Spectrum Distribution

The spectral output curve (relative intensity vs. wavelength) centers around the typical peak wavelength of 632 nm with a bandwidth of approximately 20 nm. This confirms the brilliant red color emission characteristic of the AlGaInP semiconductor material used in the LED chips.

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

The I-V characteristic curve shows the exponential relationship typical of diodes. At the recommended operating current of 10-20 mA, the forward voltage typically falls between 1.9V and 2.1V. Designers must use this curve to ensure the driving circuit provides adequate voltage to achieve the desired current, incorporating a series current-limiting resistor as standard practice for LED driving.

3.3 Forward Current Derating Curve

This graph illustrates the maximum allowable continuous forward current as a function of the ambient temperature. As temperature increases, the maximum permissible current decreases linearly to prevent overheating and ensure long-term reliability. For example, at the maximum operating temperature of 85°C, the allowable continuous current is significantly lower than the 25 mA rating at 25°C. This is crucial for designs operating in elevated temperature environments.

4. Mechanical and Packaging Information

4.1 Package Dimensions

The display has a standard through-hole DIP (Dual In-line Package) footprint. Key dimensions include the overall height, digit size, and pin spacing. The pin spacing is on a standard 0.1-inch (2.54mm) grid. The drawing specifies all critical lengths, widths, and diameters with a standard tolerance of ±0.25mm unless otherwise noted. Engineers must refer to this drawing for accurate PCB hole placement and clearance requirements.

4.2 Internal Circuit Diagram and Polarity

The internal schematic shows the common-anode configuration of the seven segments and the decimal point (if present). All segment cathodes are separate, while the anodes for all segments are connected internally to a common pin. Correct identification of the common anode pin and the individual cathode pins is essential for proper circuit connection. The datasheet provides a pinout diagram correlating physical pin numbers to segment labels (A, B, C, D, E, F, G, DP).

5. Soldering and Assembly Guidelines

The device is rated for a maximum soldering temperature of 260°C for up to 5 seconds. This is compatible with standard wave soldering processes. For manual soldering, a temperature-controlled iron should be used, and contact time per pin should be minimized to prevent thermal damage to the plastic housing and the internal wire bonds. The device should be stored in its original anti-static packaging in a dry environment prior to use.

6. Packaging and Ordering Information

6.1 Packing Specifications

The standard packing flow is: 26 pieces per tube, 88 tubes per box, and 4 boxes per carton. This totals 9,152 pieces per master carton.

6.2 Label Explanation

The product label contains several codes: CPN (Customer's Part Number), P/N (Manufacturer's Part Number: ELS-322SURWA/S530-A3), QTY (Quantity), CAT (Luminous Intensity Rank or category), and LOT No. (Traceable production lot number). Understanding the CAT code is important for selecting displays with matched brightness.

7. Application Design Considerations

7.1 Driving Circuit Design

As a common-anode display, it is typically driven by connecting the common anode to the positive supply voltage (V_CC) through a current-limiting resistor. Each segment cathode is then connected to a current sink, usually a microcontroller I/O pin or a dedicated driver IC (like a 74HC595 shift register or a MAX7219 display driver). The value of the current-limiting resistor is calculated using the formula: R = (V_CC - V_F) / I_F, where V_F is the forward voltage of the segment (typically 2.0V) and I_F is the desired forward current (e.g., 10-20 mA). For a 5V supply and a 15mA target current: R = (5V - 2.0V) / 0.015A = 200 Ω. A standard 220 Ω resistor would be a suitable choice.

7.2 Multiplexing Considerations

For multi-digit displays, multiplexing is used to control many segments with fewer I/O pins. In this scheme, digits are illuminated one at a time in rapid succession. The peak forward current rating (60mA at 1/10 duty cycle) becomes relevant here. When multiplexing, the instantaneous current per segment during its brief on-time can be higher than the continuous DC rating, as long as the average current over time remains within safe limits. This allows for brighter perceived intensity.

7.3 ESD (Electrostatic Discharge) Precautions

The LED display is sensitive to electrostatic discharge. Proper ESD handling procedures must be followed during assembly and handling to prevent latent damage or immediate failure. Recommended measures include using grounded wrist straps, ESD-safe workstations with conductive mats, and ionizers in areas with insulating materials. All equipment used in assembly should be properly grounded.

8. Technical Comparison and Differentiation

Compared to older technologies or smaller displays, the ELS-322SURWA/S530-A3 offers a balance of size, brightness, and efficiency. The use of AlGaInP material provides a high-efficiency red emission. The 0.3-inch digit height is a common size offering a good compromise between readability and PCB space consumption. Its through-hole design makes it robust and suitable for applications where vibration or manual insertion is a factor, compared to surface-mount alternatives.

9. Frequently Asked Questions (FAQ)

9.1 What is the purpose of the luminous intensity categorization (CAT)?

The CAT code groups displays based on their measured luminous output. This allows designers to select parts from the same intensity bin to ensure uniform brightness across all digits in a multi-digit display, avoiding noticeable variations in segment brightness.

9.2 Can I drive this display directly from a 3.3V microcontroller pin?

Possibly, but careful calculation is needed. With a typical V_F of 2.0V, the voltage headroom (3.3V - 2.0V = 1.3V) is sufficient to drive a current-limited segment. Using the formula R = 1.3V / I_F, for a 10mA current you would need a 130 Ω resistor. However, ensure the microcontroller pin can sink the required current (e.g., 10-20mA per segment). For multiple segments on one pin, a driver IC is strongly recommended.

9.3 Does this display have a decimal point?

The part number ELS-322SURWA/S530-A3 and the internal circuit diagram should be consulted. The \"A3\" suffix and the presence of a \"DP\" (Decimal Point) pin in the diagram indicate that this specific variant includes a decimal point LED.

10. Practical Design Example

Scenario: Designing a simple 3-digit voltmeter readout using a microcontroller.

Implementation: Three ELS-322SURWA/S530-A3 displays would be used. The common anode pins of each digit would be connected to three separate microcontroller pins configured as outputs (to enable digit multiplexing). All segment cathode pins (A-G, DP) for all three digits would be connected together and then connected to eight microcontroller pins (or a shift register) configured as current sinks. Software would sequentially turn on one digit's anode at a time, while setting the pattern for its segments via the cathode lines. The persistence of vision creates the illusion of a stable 3-digit number. The current-limiting resistors can be placed on either the common anode lines (one per digit) or on each individual cathode line (eight resistors). Placing them on the cathodes is often preferred for more uniform current sharing.