The LP2997 DDR-II Termination Regulator is a digital regulator produced by National Semiconductor Corporation. The regulator adopts a linear topology and can provide 500mA of continuous current and transient current peaks up to 900mA, and has low output voltage offset, source and sink current, no external resistors and other features. In addition, LP2997 also has the Suspend to Ram (STR) function, which can tri-state the VTT output when SD pin is pulled low, but VREF will remain active.
The LP2997 linear regulator is designed to meet JEDEC SSTL‑18 specifications for DDR‑II memory termination. It provides a high‑speed operational amplifier, active low shutdown (STR) pin, and a V SENSE pin for superior load regulation. The device can source and sink up to ±0.5 A while maintaining VTT at VDDQ/2.
The datasheet includes pin descriptions, ordering information, absolute maximum ratings, electrical characteristics, thermal dissipation guidelines, and recommended PCB layout and capacitor selections for optimal performance in DDR‑II applications.
| Continuous Output Current | 500 mA |
|---|---|
| Transient Peak Current | 900 mA |
| Quiescent Current (active) | 320 µA typical |
| Shutdown Quiescent Current | 115 µA typical |
| Thermal Shutdown Temperature | 165 °C |
The LP2997 can deliver a continuous output current of 500 mA.
When the SD pin is pulled low, the VTT output tri‑states for suspend‑to‑RAM while the VREF output remains active.
An output capacitor of at least 100 µF with low ESR is recommended for SSTL‑18 applications.
The device enters thermal shutdown at 165 °C.