Circuitry and methods for improving differential signals that cross power domains

Abstract

Disclosed herein are circuitry and methods for improving differential signals that cross power domains. In an example embodiment, the power supply domain boundary along the output paths that generate the differential signal is staggered, such that the boundary occurs at an odd numbered stage in one differential output path and at an even numbered stage in the other differential output. Defining the power supply domain boundary in this manner can help ensure that the same logical state is present at the boundary in either of the differential output paths. This same logic signal should affect subsequent stages similarly from a speed perspective, and so should similarly affect the differential signals generated by each of the output paths. This means, among other things, that the differential signal as generated should tend to cross nearer to a midpoint voltage, which increases its compliance with certain integrated circuit specifications such as the Vox specification used for the differential data strobe in an SDRAM.