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 , ISO7230C , ISO7230M , ISO7231C , ISO7231M , ISO7240C , ISO7240CF , ISO7240M , ISO7241C , ISO7241M , 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
This design guide helps system designers of galvanically isolated systems to begin designing with TI's broad portfolio of digital isolators and isolated functions in the shortest time possible. This portfolio includes the ISO78xx family of 5.7-kVrms reinforced digital isolators, the ISO67xx and ISO77xx family of 5-kVrms digital isolators, the ISO73xx family of 3-kVrms digital isolators, and the ISO71xx family of 2.5-kVrms digital isolators, among others. This document explains the basic operating principle of an isolator, suggests where to place it within a system design, and recommends guidelines for an electromagnetic compatible (EMC) circuit-board design. When looking for a reliable and robust upgrade to your optocoupler designs, consider TI's pin-to-pin opto-emulator products.
Further information is available in the respective product data sheets and the EVM manuals.
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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.