In the TPS61098x family, different versions are provided. Refer to Section 5 for version details and select the right version for target applications. It is OK to use only one output rail, either V_(MAIN) or V_(BUS), as long as it suits the application.

In this example, dual rails of 3.3 V and 3 V are required to power both MCU and subsystem, so the TPS610981 is selected.