One common design challenge for space applications is the need to generate a negative voltage rail. This application note illustrates how to design an inverting buck-boost using the radiation tolerant TPS7H4010-SEP. Radiation tolerant devices are needed to shield against single event effects and dose effects in LEO™ applications. The TPS7H4010-SEP is rated for 30-krad (Si) for total ionizing dose and 43 MeV*cm2/mg for singe event latch-up immunity. This topology takes a positive input voltage and create a regulated negative output voltage. This application note details design considerations and simulation results, so that designers can scale the design to different requirements. The document also includes experimental results and configuration instructions to regulate voltage rails of -12 V, -6 V, and -1.8 V from a 12-V input and a 5-V input for the -6 V and -1.8 V rails.