LM1572

1.5A, 500kHz Step-down Voltage Regulator

General Description

The LM1572 is a 500kHz step-down (buck) switching volt-

age regulator capable of driving up to 1.5A in to a load while

occupying a very small PCB area. Current Mode Control

results in superior transient response and regulation over a

wider range of operating conditions. National’s advanced

analog bipolar, CMOS plus DMOS process enables high

efficiency at high switching frequency, and the internal

150m

Ω MOSFET switch provides more power from a

smaller package.

The LM1572 has programmable soft-start and frequency

foldback to limit the inrush current, and a TTL compatible

shutdown for easy sequencing. It draws 2.3mA of supply

current in standby mode, and only 26µA in shutdown mode.

The LM1572 is available in a TSSOP-16 package with an

adjustable output or fixed outputs of 5V and 3.3V. The ad-

justable version can be set between 2.42V and 5V.

Features

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500kHz clock allows small, surface mount components

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150m

Ω MOSFET switch

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Guaranteed load current of 1.5A

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Current mode control

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Programmable soft-start

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Internally set slope compensation

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TTL compatible shutdown

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Fixed 5V, 3.3V or adjustable output

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Low shutdown supply current of 26µA

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Cycle-by-cycle current limit

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Short-circuit protection and thermal protection

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TSSOP-16 package

Applications

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LCD Monitors and TVs

n

Set-Top Boxes

n

Cable Modems

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Down conversion from 12V in local/distributed systems

Typical Applications (Fixed/Adjustable Voltage Parts)

20033313

July 2002

© 2002 National Semiconductor Corporation

DS200333

www.national.com