LP2997MRX/NOPB

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. The LP2997 is a linear bus termination regulator designed to meet the JEDEC requirements of SSTL-18. The output, VTT is capable of sinking and sourcing current while regulating the output voltage equal to VDDQ / 2. The output stage has been designed to maintain excellent load regulation while preventing shoot through. The LP2997 also incorporates two distinct power rails that separates the analog circuitry from the power output stage. This allows a split rail approach to be utilized to decrease internal power dissipation. It also permits the LP2997 to provide a termination solution for the next generation of DDR-SDRAM memory (DDRII).

Applications

• DDR-II Termination Voltage
• SSTL-18 Termination

Key features

• 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
• 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.