Memory devices, systems and methods using selective on-die termination

Abstract

A memory system includes first and second memory devices having commonly connected data terminals and commonly connected memory control signal terminals, e.g., devices in respective first and second independently selectable memory banks that share common data lines and common memory control signal lines, such as column address strobe, row address strobe, write enable, and address signal lines. The first and second memory devices includes respective selective on-die termination (ODT) circuits configured to selectively provide first and second termination impedances at their respective data terminals responsive to a memory control signal at the commonly connected memory control signal terminals. The selective ODT circuits may produce the first termination impedance responsive to a memory write operation, and may produce the second termination impedance responsive to a memory read operation and/or expiration of a predetermined time interval following termination of the memory write operation. Preferably, the first termination impedance is less than the second termination impedance, and the selective ODT circuits provide the first termination impedance responsive to the memory write operation irrespective of which of the first and second memory devices is being written to.