THVD4431 has two termination resistors of nominal 120Ω, one across R1/R2 and another across R3/R4 bus pins in RS-485 mode. Both termination resistors are enabled or disabled using TERM_TX and TERM_RX control pins as described in Table 7-2 of the THVD4431 data sheet. Both the termination resistors can be enabled or disabled independent of the state of driver or receiver. Termination is OFF in RS-232 loopback, RS-232 3T5R, RS-485 loopback, unpowered and thermal shutdown modes.

While the Maxlinear XR34350 and SP339E/B multiprotocol transceivers also provide 120Ω termination resistor across R3/R4, the transceivers do not offer one across R1/R2 bus pins. Therefore, THVD4431 is more flexible in RS-485 full duplex applications where it can be used at middle nodes or end nodes without the need of additional discrete termination resistor as well as control circuit, which helps save significant PCB area. An example RS-485 full duplex configuration with THVD4431 is shown in Figure 2-5.

Figure 2-5 THVD4431 in Full Duplex RS-485 Network