The LM3485 is a high-efficiency PFET switching regulator controller that can be used to
quickly and easily develop a small, low-cost, switching buck regulator for a wide range of
applications. The hysteretic control architecture provides for simple design without any
control-loop stability concerns using a wide variety of external components. The PFET architecture
also allows for low component count as well as ultralow dropout, 100% duty cycle operation. Another
benefit is high efficiency operation at light loads without an increase in output ripple.
Current limit protection is provided by measuring the voltage across the
RDS(ON) of the PFET, thus eliminating the need for a sense resistor. The
cycle-by-cycle current limit can be adjusted with a single resistor, ensuring safe operation over a
range of output currents.
