LM3489 Hysteretic PFET Buck Controller with Enable Pin | TI.com

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Hysteretic PFET Buck Controller with Enable Pin


Recommended alternative parts

  • LM25085A  -  4.5-42V wider Vin with COT topology


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.


  • 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


Compare all products in Buck controllers (external switch) Email Download to Excel
Part number Order Vin (Min) (V) Vin (Max) (V) Vout (Min) (V) Vout (Max) (V) Iout (Max) (A) Regulated outputs (#) Number of Phases Switching frequency (Min) (kHz) Switching frequency (Max) (kHz) Iq (Typ) (mA) Features Duty cycle (Max) (%) Operating temperature range (C) Rating Package Group Type Control mode
LM3489 Order now 4.5     35     1.239     35     4     1     1     50     1400     0.28     Enable     100     -40 to 125     Catalog     VSSOP | 8     Controller     Hysteretic    
LM3489-Q1 Order now 4.5     35     1.239     35     4     1     1     50     1400     0.28     Enable     100     -40 to 125     Automotive     VSSOP | 8     Controller     Hysteretic