9.1 Application Information

ISO71xx use single-ended TTL-logic switching technology. Its supply voltage range is from 3 V to 5.5 V for both supplies, V_CC1 and V_CC2. When designing with digital isolators, it is important to note that due to the single-ended design structure, digital isolators do not conform to any specific interface standard and are only intended for isolating single-ended CMOS or TTL digital signal lines. The isolator is typically placed between the data controller (that is, μC or UART), and a data converter or a line transceiver, regardless of the interface type or standard.

9.2 Typical Applications

9.2.1 Isolated Data Acquisition System for Process Control

ISO71xx combined with TI's precision analog-to-digital converter and mixed signal micro-controller can create an advanced isolated data acquisition system as shown in Figure 17.

Figure 17. Isolated Data Acquisition System for Process Control

9.2.1.1 Design Requirements

Unlike optocouplers, which need external components to improve performance, provide bias, or limit current, ISO71xx only needs two external bypass capacitors to operate.

9.2.1.2 Detailed Design Procedure

Figure 18. Typical ISO7131 Circuit Hook-up

Figure 20. Typical ISO7141 Circuit Hook-up

Figure 19. Typical ISO7140 Circuit Hook-up

9.2.1.3 Application Curves

Typical eye diagrams of ISO71xx (see Figure 21, Figure 22, and Figure 23) indicate low jitter and wide open eye at the maximum data rate.

Figure 21. Typical Eye Diagram at 40 MBPS, PRBS 2¹⁶ - 1, 2.7-V Operation

Figure 23. Typical Eye Diagram at 50 MBPS, PRBS 2¹⁶ - 1, 5-V Operation

Figure 22. Typical Eye Diagram at 40 MBPS, PRBS 2¹⁶ - 1, 3.3-V Operation

9.2.2 Isolated RS-485 Interface

Figure 24. Isolated RS-485 Interface

9.2.2.1 Design Requirements

See previous Design Requirements.

9.2.2.2 Detailed Design Procedure

See previous Detailed Design Procedure.

9.2.2.3 Application Curves

See previous Application Curves.