1. Overview

Digital isolators are electronic components that enable signal transmission between circuits or systems with different voltage levels while maintaining electrical isolation. They utilize semiconductor technologies (e.g., capacitive, inductive, or optical coupling) to replace traditional optocouplers. These devices are critical in modern systems for ensuring safety, reducing noise interference, and enabling communication in high-voltage environments.

2. Main Types and Functional Classification

3. Structure and Components

A typical digital isolator consists of: (1) Input circuit with signal conditioning; (2) Isolation barrier (e.g., SiO2 capacitive layer or micro-transformer core); (3) Output circuit with amplification/reconstruction; (4) Dual-die packaging with reinforced insulation. Advanced products integrate signal and power isolation in single chips.

4. Key Technical Specifications

5. Application Fields

• Industrial automation (PLC, motor drives)
• Medical equipment (ECG machines, patient monitors)
• Automotive systems (BMS, OBC for EVs)
• Renewable energy (solar inverters, grid-tied systems)
• Telecommunications (5G base stations, optical transceivers)

6. Leading Manufacturers and Products

7. Selection Guidelines

1. Define isolation voltage and safety certification (e.g., UL, VDE)
2. Match data rate with system requirements
3. Consider channel count and directionality
4. Evaluate power budget and PCB space constraints
5. Check environmental specifications (temperature, vibration)

8. Industry Trends

Future development focuses on: (1) Integration of isolation and level-shifting functions; (2) 3D packaging for miniaturization; (3) Enhanced immunity to electromagnetic interference (EMI < 150 V/m); (4) System-level isolation solutions combining signal/power transfer. The market is projected to grow at 12% CAGR until 2028, driven by EV and industrial IoT adoption.

Application Case

In electric vehicles, digital isolators like TI's ISO7741 are used in battery management systems to isolate high-voltage battery packs (up to 1000V) from low-voltage control circuits, enabling safe CAN bus communication with 50kV/ s common-mode transient immunity (CMTI).