LP2997 Datasheet, PDF (1/12 Pages) National Semiconductor (TI) – DDR-II Termination Regulator

June 2004
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_SENSE pin to provide superior
load regulation and a V_REF output as a reference for the
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_TT output will
tri-state providing a high impedance output, but, V_REF will
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
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© 2004 National Semiconductor Corporation DS201094
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