LP2997

DDR-II Termination Regulator

General Description

The LP2997 linear regulator is designed to meet the JEDEC

SSTL-18 specifications for termination of DDR-II memory.

The device contains a high-speed operational amplifier to

provide excellent response to load transients. The output

stage prevents shoot through while delivering 500mA con-

tinuous current and transient peaks up to 900mA in the

application as required for DDR-II SDRAM termination. The

LP2997 also incorporates a V

load regulation and a V

chipset and DIMMs.

An additional feature found on the LP2997 is an active low

shutdown (SD) pin that provides Suspend To RAM (STR)

functionality. When SD is pulled low the V

tri-state providing a high impedance output, but, V

remain active. A power savings advantage can be obtained

in this mode through lower quiescent current.

Features

n

Source and sink current

n

Low output voltage offset

n

No external resistors required

n

Linear topology

n

Suspend to Ram (STR) functionality

n

Low external component count

n

Thermal Shutdown

n

Available in SO-8, PSOP-8 packages

Applications

n

DDR-II Termination Voltage

n

SSTL-18 Termination

Typical Application Circuit

20109418

June 2004

© 2004 National Semiconductor Corporation

DS201094

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