Description
●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.
●Features
●• Easy-to-Use Control Methodology
●• No Control-Loop Compensation Required
●• 4.5-V to 35-V Wide Input Range
●• 1.242-V to VIN Adjustable Output Range
●• High Efficiency 93%
●• ±1.3% (±2% Over Temp) Internal Reference
●• 100% Duty Cycle
●• Maximum Operating Frequency > 1 MHz
●• Current Limit Protection
●Applications
●• Set-Top Box
●• DSL or Cable Modem
●• PC/IA
●• Auto PC
●• TFT Monitor
●• Battery-Powered Portable Applications
●• Distributed Power Systems
●• Always On Power
