LM3489MMX/NOPB

The LM3489 device is a high-efficiency PFET switching regulator controller that can be used to quickly and easily develop a small, cost-effective, 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. A dedicated enable pin provides a shutdown mode drawing only 7 μA. Leaving the enable pin unconnected defaults to on. Current limit protection can be implemented by measuring the voltage across the PFET’s RDS(ON), thus eliminating the need for a sense resistor. A sense resistor may be used to improve current limit accuracy if desired. The cycle-by-cycle current limit can be adjusted with a single resistor, ensuring safe operation over a range of output currents.

Applications

• Set-Top Boxes
• DSL or Cable Modems
• PC/IA Auto PCs
• TFT Monitors
• Battery-Powered Portable Applications
• Distributed Power Systems Always-On Power
• High-Power LED Drivers
• Automotive

Key features

• Qualified for Automotive Parts
• AEC-Q100 Qualified With the Following Results: Device Temperature Grade 1: -40°C to 125°C Ambient Operating Temperature Range Device HBM ESD Classification Level 2 Device CDM ESD Classification Level C5
• Easy-to-Use Control Methodology
• No Control Loop Compensation Required
• Wide 4.5-V to 35-V Input Range
• 1.239 V to VIN Adjustable Output Range
• High Efficiency: 93%
• ±1.3% (±2% Over Temperature) Internal Reference
• 100% Duty Cycle Operation
• Maximum Operation Frequency >1 MHz
• Current Limit Protection
• Dedicated Enable Pin (on if Unconnected)
• Shutdown Mode Draws Only 7-μA Supply Current
• 8-Pin VSSOP Package