LM3485  Product Folder

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 ultra-low 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 PFET's R_DS(ON), 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.

• Easy to use control methodology
• No control loop compensation required
• 4.5V to 35V wide input range
• 1.242V to V_IN adjustable output range
• High Efficiency 93%
• ±1.3% (±2% over temp) internal reference
• 100% duty cycle
• Maximum operating frequency > 1MHz
• Current limit protection
• MSOP-8

• Set-Top Box
• DSL/Cable Modem
• PC/IA
• Auto PC
• TFT Monitor
• Battery Powered Portable Applications
• Distributed Power Systems
• Always On Power