Solution to DQS postamble ringing problem in memory chips
The disclosed system and method significantly reduce or eliminate DQS postamble ringing problem in modern high-speed memory chips, allowing the memory chips to be operated at significantly faster clock speeds. The external strobe signal (XDQS) may be used to generate at least two derivative strobe signals therefrom. Instead of the XDQS signal, the derivative strobe signals are then used, in a predetermined order, to clock in or strobe the data to be written into memory cells. The last generated derivative strobe signal may be used to finally transfer the data bits into memory cells. Once the last of the derivative strobe signals is activated, and so long as there are no more data writes pending in the command pipe for the next clock cycle, the rising or falling edge of the last derivative strobe signal can be detected to turn off further generation of the strobe signals prior to any onset of postamble ringing on the XDQS signal. Thus, false data may not get “clocked in” or written into the memory chip because of postamble ringing. This prevents data corruption and preserves the integrity of the data written into a memory chip.
Micron Technology, Inc.
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Wen Christopher K. Sugato
Li Morzano Mukherjee