Maxim Integrated got you covered on designing all in 48V automotive compliant buck converter. Link here
Ever-tightening automotive fuel emission standards are becoming challenging. The gasoline engine needs the help of an electric motor to meet these standards, leading to the introduction of mild hybrid electric vehicles (MHEV) with higher battery voltages. 48V hybrids are in production today and are proliferating. A 48V buck converter with integrated MOSFETs in an advanced CMOS process helps meet these standards by withstanding high-voltage load-dump transients and operating with low EMI, low duty cycles, and high efficiency.