Data output buffer whose mode switches according to operation frequency and semiconductor memory device having the same

Abstract

A data output buffer switches it operating mode according to its operating frequency. The data output buffer includes a delay control unit, and a buffer unit. The buffer unit provides data of an internal buffer input line to an external buffer output line. The delay control unit generates a buffer enable signal corresponding to a received reference control signal. The buffer unit blocks the provision of the data to the buffer output line in response to a deactivation of the buffer enable signal. The buffer enable signal remains in an activated state when the period of the reference control signal is shorter than a reference period. The data output buffer may be included in a semiconductor memory device.