Integrated circuit memory devices having programmable latency periods

Abstract

Integrated circuit memory devices include a column select signal generator which generates a column select signal (CSL) having leading and trailing edges and a preferred timing controller. The timing controller, which is electrically coupled to the column select signal generator and is responsive to at least one latency state signal (e.g., CLy), adjusts the timing of at least one of the leading and trailing edges of the column select signal pulse as a function of the value of the at least one latency state signal. Here, the value of the latency state signal can be adjusted to cause a shift in the timing of the column select signal (CSL) and thereby reduce the likelihood of reading errors. In particular, the timing controller is responsive to a first internal clock signal (e.g., PCLK) and generates first and second control signals as CSLE and CSLD. The column select signal generator is responsive to the first and second control signals. The first control signal is preferably delayed and inverted relative to the first internal clock signal by a first delay and the second control signal is preferably delayed relative to the first internal clock signal by a second delay which is less than the first delay. The timing controller also adjusts the timing of at least one of the leading and trailing edges of the column select signal by adjusting the values of the first and second delays as a function of the value of the at least one latency state signal.