Method of eliminating signal skew in a synchronized dynamic

Abstract

A method is proposed for eliminating signal skew in an SDRAM (Synchronized Dynamic Random-Access Memory) device resulting from the data signal being attenuated into different input signal amplitudes at the respective input points into the memory cells in the SDRAM device. The method is intended for use on a SDRAM device having at least a first memory cell and a second memory cell which are connected to a common signal line which transmits a data signal to both the first and the second memory cells. Due to the data signal being gradually attenuated along the signal line, the input signal amplitudes at the respective input points into the first and second memory cells are different, which would otherwise cause signal skew. In accordance with this method, the trigger voltage levels of the memory cells are adjusted in such a manner as to be substantially equal to the respective input signal amplitudes at a specific trigger time, so that all the memory cells can be triggered substantially concurrently without the occurrence of signal skew. Typically, the trigger voltage levels can be adjusted by adjusting the respective threshold voltages or current gains of the NMOS transistor and PMOS transistor in an inverter used as the I/O buffer of each memory cell. By this method, the adjustment can be easily achieved without having to provide additional circuitry to the SDRAM device. This method is therefore useful in solving the problem of signal skew in the SDRAM device.