LM2652

1.5A, Dual High Performance Synchronous Buck

Regulator

General Description

The LM2652 is a monolithic dual synchronous buck regula-

tor designed for low output voltages. Special attention to

power sequencing, voltage accuracy and start-up character-

istics has been made to enable a simple solution to the

challenging requirements of FPGA & DSP power. Four inte-

grated FET power switches ensure high efficiency, minimal

external components and maximum ease-of-use. The IC can

accept an input of 2.7V to 5.5V and deliver 1.5A per channel.

The bias and power inputs can run from different rails to

balance system power. Output voltages are factory program-

mable from 0.8V to 3.3V in 50mV steps. The LM2652 is

available in two switching frequency options (650kHz and

1300kHz) and both options can be synchronized to an ex-

ternal clock of 300-1600kHz. The two switching channels run

180˚ out of phase to reduce input capacitor size and cost.

Output fault protection is provided by the use of cycle-by-

cycle current limit and frequency fold-back. Separate soft-

start, power good flags and output enables allow for power

sequencing flexibility.

Features

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Dual 1.5 Amp outputs

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Output voltage factory set in 50mV steps from 0.8V to

3.3V

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Input voltage from 2.7V to 5.5V

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2% reference accuracy

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4 internal 80m

Ω synchronous switches

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180˚ out of phase operation

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Independent enables (CMOS compatible)

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Separate Power Good flags

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650kHz or 1300kHz switching frequency

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PLL synchronization to an external clock

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Programmable soft-start

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Supports all-ceramic output capacitors

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TSSOP-28 Exposed Pad package

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Current limit and thermal shutdown protection

Applications

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Cable Modems

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xDSL Modems

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DSP, FPGA and microprocessor power

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Local Regulation

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Set-Top Box

Typical Application

20117201

ADVANCE INFORMATION

January 2005

© 2005 National Semiconductor Corporation

DS201172

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