HDSP-A213-CD000 · 7.6 mm(0.3 inch) Micro Bright Seven Segment Displays# Technical Documentation: HDSPA213CD000 Alphanumeric Display
Manufacturer : AGILENT (now Keysight Technologies)
Component Type : 5x7 Dot Matrix Alphanumeric Display (Common Anode, High-Efficiency Red)
Document Version : 1.0
---
## 1. Application Scenarios (45% of content)
### Typical Use Cases
The HDSPA213CD000 is a single-character, 5x7 dot matrix LED display designed for alphanumeric character presentation in embedded systems. Each character is formed by illuminating specific LEDs within the 5-column × 7-row grid, allowing display of uppercase letters (A-Z), numbers (0-9), and limited symbols.
Primary applications include:
- Status Indicators : Displaying system states (RUN, STOP, ERR), mode selections (AUTO, MAN), or simple codes.
- Data Readouts : Showing numeric values (temperatures, counts, voltages) or short alphanumeric identifiers in instrumentation.
- User Interface Elements : As part of a multi-character display array for simple menus, prompts, or scrolling text in industrial controls.
### Industry Applications
- Industrial Automation : Panel meters, PLC I/O status displays, motor drive parameter readouts.
- Test & Measurement Equipment : Benchtop power supplies, signal generators, multimeters for displaying setpoints or measured values.
- Telecommunications : Channel status or error code display in network hardware.
- Medical Devices : Simple parameter display on monitors or diagnostic equipment (where high brightness is advantageous).
- Consumer Electronics : Appliances, audio equipment, or vintage computing projects requiring a retro, highly legible display.
### Practical Advantages and Limitations
Advantages:
- High Brightness & Efficiency : Utilizes GaAsP on GaP LED technology, offering excellent luminous intensity (typ. 7.0 mcd min. per segment at 10 mA), suitable for well-lit or outdoor-adjacent environments.
- Wide Viewing Angle : Typically 100° or more, ensuring visibility from various positions.
- Robust & Long-Lifespan : Solid-state LED construction provides high reliability and long operational life.
- Simple Interface : Directly driven by microcontroller GPIO pins or shift registers; no complex controller needed for a single character.
- Common Anode Configuration : Simplifies multiplexing in multi-digit designs and is often easier to interface with common sink-driver ICs.
Limitations:
- Limited Character Set : The 5x7 resolution restricts font complexity; lowercase characters and complex symbols may be poorly rendered.
- Single Character : Requires multiple units for multi-character messages, increasing PCB footprint and driver complexity.
- Power Consumption : Higher than modern LCDs, especially when displaying many lit segments. Requires current-limiting resistors for each cathode column.
- Color Monochrome : Only available in high-efficiency red. Not suitable for multi-color applications.
- Refresh Requirement : In multiplexed arrays, careful timing design is needed to avoid flicker and ghosting.
---
## 2. Design Considerations (35% of content)
### Common Design Pitfalls and Solutions
1. Pitfall: Overdriving LEDs without current limiting.
* Solution: Always use series current-limiting resistors on each cathode pin. Calculate resistor value based on supply voltage (Vcc), LED forward voltage (Vf ~1.8V typ.), and desired segment current (Iseg, typically 10-20 mA for full brightness). Example: For Vcc=5V, Iseg=10mA, R = (5V - 1.8V) / 0.01A = 320Ω (use 330Ω standard).
2. Pitfall: Insufficient drive current from microcontroller pins.
* Solution: Microcontroller GPIO
