Texas Instruments Hysteretic PFET Buck Controller with Enable Pin LM3489EVAL/NOPB LM3489EVAL/NOPB 数据表
产品代码
LM3489EVAL/NOPB
User's Guide
SNVA160A – May 2006 – Revised April 2013
AN-1471 LM3489 Demonstration Board
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Introduction
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.
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.
The current limit protection can be implemented 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.
resistor, ensuring safe operation over a range of output currents.
This LM3489 demonstration board provides a 3.3 V output with 500 mA nominal load capability (maximum
1A) from a wide input voltage range of 7 V to 28 V. The reference design is optimized for overall
conversion efficiency. This document contains the demo board schematic, PCB layout, Bill of Materials
(BOM) and typical operating waveforms are provided for reference.
1A) from a wide input voltage range of 7 V to 28 V. The reference design is optimized for overall
conversion efficiency. This document contains the demo board schematic, PCB layout, Bill of Materials
(BOM) and typical operating waveforms are provided for reference.
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Evaluation Board Schematic
Figure 1. LM3489 Evaluation Board Schematic
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SNVA160A – May 2006 – Revised April 2013
AN-1471 LM3489 Demonstration Board
Copyright © 2006–2013, Texas Instruments Incorporated