Data output buffer control circuit for a semiconductor memory device

Abstract

A data output buffer control circuit for a semiconductor memory device assures a column address setup time and a valid data setup time in EDO mode by eliminating short glitches in the data output buffer. The circuit assures the column address setup time by disabling the data output buffer for a predetermined period of time after an address transition, regardless of the state of a column address strobe signal. The circuit assures the setup time for valid data by sensing when the address is set up relative to when the column address strobe signal is activated, and then enabling the data output buffer so as to maintain invalid data in the data output buffer long enough to prevent a short glitch in the data output buffer if the column address is set up before the column address strobe signal is activated. The circuit includes a pulse generator for generating a pulse signal each time it senses a column address transition, and a latch circuit for combining the pulse signal with the column address strobe signal so as to generate a buffer control signal for enabling and disabling the data output buffer.