LM3485

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SNVS178F – MAY 2004 – REVISED SEPTEMBER 2009

LM3485 Hysteretic PFET Buck Controller

Check for Samples: LM3485

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FEATURES

APPLICATIONS

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Easy to use control methodology

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Set-Top Box

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No control loop compensation required

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DSL/Cable Modem

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4.5V to 35V wide input range

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PC/IA

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Auto PC

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High Efficiency 93%

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TFT Monitor

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±1.3% (±2% over temp) internal reference

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Battery Powered Portable Applications

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100% duty cycle

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Distributed Power Systems

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Maximum operating frequency > 1MHz

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Always On Power

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Current limit protection

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MSOP-8

DESCRIPTION

The LM3485 is a high efficiency PFET switching regulator controller that can be used to quickly and easily

develop a small, low cost, 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.

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.

Typical Application Circuit

Connection Diagram

Figure 1. 8 Lead Plastic MSOP-8

Top View

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PRODUCTION DATA information is current as of publication date.

Copyright © 2004–2009, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.