LP2997 Datasheet | National Semiconductor

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 500m A continuous current and transient peaks up to 900m A 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 ponent count Thermal Shutdown Available in SO-8, PSOP-8 packages Applications n DDR-II Termination Voltage n SSTL-18 Termination Typical Application Circuit © 2004 National Semiconductor Corporation DS201094 .national. Connection Diagrams PSOP-8 Layout SO-8 Layout Pin Description SO-8 Pin or PSOP-8 Pin 1 2 3 4 5 6 7 8 Name GND SD VSENSE VREF VDDQ AVIN PVIN VTT Ground Shutdown Feedback pin for regulating VTT. Buffered internal reference voltage of VDDQ/2 Input for internal reference equal to VDDQ/2 Analog input pin Power input pin Output voltage for connection to termination resistors Function Ordering Information Order Number LP2997M LP2997MX LP2997MR LP2997MRX Package Type SO-8 SO-8 PSOP-8 PSOP-8 NSC Package Drawing M08A M08A MRA08A MRA08A Supplied As 95 Units per Rail 2500 Units Tape and Reel 95 Units Tape and Reel 2500 Units Tape and Reel .national. Absolute Maximum Ratings...