LP2997

LP2997 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 continuous current and transient peaks up to 900mA in the application as required for DDR-II SDRAM termination. The LP2997 also incorporates a VSENSE pin to provide superior load regulation and a VREF 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 VTT output will tri-state providing a high impedance output, but, VREF will remain active. A power savings advantage can be obtained in this mode through lower quiescent current. Features n n n n n n n n 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 SO-8, PSOP-8 packages Applications n DDR-II Termination Voltage n SSTL-18 Termination Typical Application Circuit 20109418 © 2004 National Semiconductor Corporation DS201094 www.national.com LP2997 Connection Diagrams 20109403 PSOP-8 Layout 20109404 SO-8 Layout Pin Description SO-8 Pin or PSOP-8 Pin ...