Data output control circuit of semiconductor memory device having pipeline structure

摘要

In a method of testing a semiconductor memory device having a pipeline structure, a same data is stored in a plurality of memory cells in advance. The stored data are read out from the plurality of memory cells to produce data signals and amplified as the data signals. A determining section determines whether all the data signals are same, to generate a determination result signal. In accordance with the determination result signal, one of signals associated with the amplified data signals and predetermined signals are transferred to an output section in synchronous with a synchronous signal. The output section includes a plurality of output circuits each of which provides, as an indication signal, one of a low level signal, a high level signal and a signal indicative of a high impedance state in response to each of the transferred signals. Therefore, using at least one of the indication signals, whether the plurality of memory cells are correctly operable can be tested.