The AN6575 is a synchronous four-switch buck-boost DC/DC controller capable of regulating the output voltage at, above, or below the input voltage. The AN6575 operates over a wide input voltage range of 4.5 V to 40 V to support a variety of applications. The AN6575 employs current-mode control both in buck and boost modes of operation for superior load and line regulation. The switching frequency is programmed by an external resistor. This device also features a programmable soft-start function and offers protection features including cycle-by-cycle current limiting, input undervoltage lockout (UVLO), output overvoltage protection (OVP), and thermal shutdown. The AN6575 is available in an QFN4x4-24L package, provides a very compact system solution and good thermal conductance.