The ISL78201 is an AEC-Q100 qualified 40V, 2. 5A synchronous buck or boost buck controller with a high-side MOSFET and low-side driver integrated. In Buck mode, the ISL78201 supports a wide input range of 3V to 40V. In Boost-Buck mode, the input range can be extended down to 2. 5V and output regulation can be maintained when VINdrops below VOUT, enabling sensitive electronics to remain on during cold-cranking and start-stop applications. The ISL78201 has a flexible selection of operation modes including forced PWM mode and an optional switch to PFM mode for light loads. In PFM mode, the quiescent input current is as low as 300µA and can be further reduced to 180µA with AUXVCC connected to VOUTunder 12V VINand 5V VOUTapplication. The load boundary between PFM and PWM can be programmed to cover wide applications. The low-side driver can be either used to drive an external low-side MOSFET for a synchronous buck, or left unused for a standard non-synchronous buck. The low-side driver can also be used to drive a boost converter as a preregulator that greatly expands the operating input voltage range down to 2. 5V or lower. The ISL78201 offers the most robust current protections. It uses peak current mode control with cycle-by-cycle current limiting. It is implemented with frequency foldback undercurrent limit condition; in addition, the hiccup overcurrent mode is also implemented to guarantee reliable operations under harsh short conditions. The ISL78201 has comprehensive protections against various faults including overvoltage and over-temperature protections, etc.