The AT9451 is a high frequency (1.8MHz) step-downswitching regulator with integrated internal high-sidehigh voltage power MOSFET. It provides single 0.6A (orless) highly efficient output with current mode controlfor fast loop response. The wide input range (4.2V to 40V) accommodates avariety of step-down applications under mobileenvironment input conditions. Low shutdown modequiescent current of 1μA is suitable for battery poweredapplications. High efficiency at light load condition isachieved by scaling down the switching frequency toreduce the switching and gate driving losses. Thefrequency folding technique helps prevent theinductance current from running out of control atstartup. Hot shutdown provides reliable, fault tolerantoperation.