1. Overview

Single Zener diodes are discrete semiconductor devices designed to operate in the reverse breakdown region, maintaining a stable voltage across a wide range of currents. Based on the Zener effect and avalanche breakdown mechanisms, these components are critical for voltage regulation, reference, and protection circuits. They serve as foundational elements in power supplies, analog circuits, and precision measurement systems, ensuring reliability in electronics ranging from consumer devices to industrial equipment.

2. Main Types and Functional Classification

3. Structure and Composition

Single Zener diodes consist of a heavily doped PN junction semiconductor structure, typically fabricated from silicon. The cathode terminal is marked with a band, while the anode connects to the P-type material. Advanced devices employ passivation layers (e.g., silicon dioxide) to improve stability and reliability. Common packaging includes axial leaded (DO-35, DO-41) and surface-mount (SOD-123, SOT-23) formats with glass or plastic encapsulation for environmental protection.

4. Key Technical Specifications

5. Application Fields

Key industries include:

• Power electronics (switching power supplies, DC-DC converters)
• Industrial automation (PLC voltage references, sensor interfaces)
• Consumer electronics (mobile chargers, LED drivers)
• Automotive systems (battery management, onboard charging)
• Test equipment (precision multimeters, calibration devices)

Example: The TL431 programmable Zener diode is widely used in SMPS feedback loops to achieve 1% voltage accuracy.

6. Leading Manufacturers and Products

7. Selection Guidelines

Key considerations:

1. Determine required Vz with 5% margin over operating current range
2. Calculate Pz = Vz maximum expected current
3. Select package type based on board space and thermal requirements
4. For precision applications, prioritize TC < 100ppm/ C and low Zz
5. Consider automotive-grade parts for harsh environments

8. Industry Trends

Current development trends include: - Miniaturization with advanced trench Zener structures - Integration with ESD protection in combo devices - Wide bandgap materials (SiC) for high-voltage applications - Improved temperature stability through laser trimming - Increased adoption in renewable energy systems for voltage monitoring - Growth in automotive electronics driving AEC-Q qualified parts