描述 Description

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.

特性 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
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