SLLA284G July   2022  – September 2023 ISO5451 , ISO5452 , ISO5851 , ISO5852S , ISO7142CC , ISO7142CC-Q1 , ISO721 , ISO721-Q1 , ISO721M , ISO721M-EP , ISO722 , ISO7220A , ISO7220M , ISO7221A , ISO7221B , ISO7221C , ISO7221M , ISO722M , ISO7230A , ISO7230C , ISO7230M , ISO7231A , ISO7231C , ISO7231M , ISO7240A , ISO7240C , ISO7240CF , ISO7240M , ISO7241A , ISO7241C , ISO7241M , ISO7242A , ISO7242C , ISO7242M , ISO7310-Q1 , ISO7310C , ISO7340-Q1 , ISO7340C , ISO7340FC , ISO7341-Q1 , ISO7341C , ISO7341FC , ISO7342-Q1 , ISO7342C , ISO7342FC , ISO7740 , ISO7741 , ISO7742 , ISO7760 , ISO7761 , ISO7762 , ISO7810 , ISO7820 , ISO7821 , ISO7830 , ISO7831 , ISO7840 , ISO7841 , ISO7842

 

  1.   1
  2.   Digital Isolator Design Guide
  3.   Trademarks
  4. 1Operating Principle
    1. 1.1 Edge-Based Communication
    2. 1.2 On-Off Keying (OOK) Based Communication
  5. 2Typical Applications for Digital Isolators and Isolated Functions
  6. 3Digital Isolator Selection Guide
    1. 3.1 Parameters of Interest
    2. 3.2 Isolator Families
  7. 4PCB Design Guidelines
    1. 4.1 PCB Material
    2. 4.2 Layer Stack
    3. 4.3 Creepage Distance
    4. 4.4 Controlled Impedance Transmission Lines
    5. 4.5 Reference Planes
    6. 4.6 Routing
    7. 4.7 Vias
    8. 4.8 Decoupling Capacitors
  8. 5Summary
  9. 6References
  10. 7Revision History

1 Operating Principle

Isolation is a means of preventing dc and unwanted ac currents between two parts of a system, while allowing signal and power transfer between those two parts. Electronic devices and semiconductor ICs used for isolation are called isolators. In general, an isolator can be abstracted as comprising of a high-voltage isolation component or barrier, a transmitter (TX) to couple signal into one side of the isolation component, and a receiver (RX) to convert the signal available on the other side of the isolation component into digital levels.

TI's isolators use SiO2 (silicon dioxide) based, high-voltage capacitors to serve as the isolation component. For the TX and RX circuits, two different architectures are used: Edge based and On-Off Keying (OOK) based. These architectures are explained in Section 1.1 and Section 1.2.