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.
| Type | Functional Features | Application Examples |
|---|---|---|
| Capacitive Isolators | Use high-frequency capacitive coupling for signal transfer. Low power consumption, supports high data rates. | Industrial motor drives, PLC systems |
| Inductive (Magnetic) Isolators | Utilize miniature transformers for isolation. High noise immunity, supports bidirectional communication. | Automotive BMS, battery chargers |
| Optocoupler-Based Digital Isolators | Hybrid design combining LED and CMOS detectors. Low cost, moderate speed. | Consumer electronics, home appliances |
| Multi-Channel Isolators | Integrate multiple isolation channels in one package. Supports complex signal routing. | Data acquisition systems, industrial IoT gateways |
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.
| Parameter | Unit | Importance |
|---|---|---|
| Isolation Voltage (Viso) | Vrms | Determines safety level (e.g., 2500-5000Vrms for industrial use) |
| Data Rate | Mbps | Defines maximum signal transmission speed (1-150 Mbps) |
| Propagation Delay | ns | Impacts system timing accuracy (Typ. 10-50 ns) |
| Power Consumption | mW | Crucial for battery-powered devices |
| Operating Temperature | C | Specifies environmental tolerance (-40 to +125 C) |
| Manufacturer | Representative Product | Key Specifications |
|---|---|---|
| Analog Devices | ADN4654 | 150Mbps, 5kVrms isolation, 4-channel |
| Texas Instruments | ISO7841 | 100Mbps, 8kV CMTI, quad-channel |
| Silicon Labs | SI8640 | 150Mbps, 2.5kVrms, 4-channel |
| Infineon | BDx183 | 100Mbps, reinforced isolation, automotive-grade |
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.
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).