Hysteretic PFET Buck Controller with Enable Pin


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The LM3489 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, and 100% duty cycle operation. Another benefit is high efficiency operation at light loads without an increase in output ripple. A dedicated Enable Pin (Enabled if left unconnected) provides a shutdown mode drawing only 7 µA.

  • Wide 4.5V to 35V input range
  • 1.239V to VIN adjustable output range
  • High efficiency 93%
  • 1.3% ( 2% over temp) internal reference
  • 100% duty cycle operation
  • Maximum operation frequency > 1MHz
  • Current limit protection
  • Dedicated enable pin (on if unconnected)
  • Shutdown mode draws on 7uA supply current
  • MSOP-8


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


Buck controllers (external switch)
LM3489 Hysteretic PFET Buck Controller with Enable Pin LM3489-Q1 Automotive Grade 4.5-35V, Hysteretic Non-Synchronous PFET Buck Controller with Enable Pin

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Evaluation board

LM3489EVAL/NOPB — Hysteretic PFET Buck Controller with Enable Pin

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Technical documentation

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Type Title Date
* User guide AN-1471 LM3489 Demonstration Board (Rev. A) Apr. 25, 2013
Certificate LM3489EVAL/NOPB EU Declaration of Conformity (DoC) Jan. 02, 2019

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