LP2997 Datasheet, PDF (1/21 Pages) National Semiconductor (TI) – DDR-II Termination Regulator

LP2997
www.ti.com
SNVS295F – MAY 2004 – REVISED APRIL 2013
LP2997 DDR-II Termination Regulator
Check for Samples: LP2997
FEATURES
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•2 Source and Sink Current
• Low Output Voltage Offset
• No External Resistors Required
• Linear Topology
• Suspend to Ram (STR) Functionality
• Low External Component Count
• Thermal Shutdown
• Available in SOIC-8, SO PowerPAD-8 Packages
APPLICATIONS
• DDR-II Termination Voltage
• SSTL-18 Termination
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 continuous 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.
Typical Application Circuit
SD
AV _IN = 2.5V
V_DDQ = 1.8V
+
C_IN
LP2997
SD
AV_IN
V_REF
V _DDQ
V _SENSE
PV_IN
V_TT
GND
+
C_REF
V_REF = 0.9V
+
C _OUT
V _TT= 0.9V
Figure 1. Typical Application Circuit
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PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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