Patent Number: 8,089,817

Title: Precise tRCD measurement in a semiconductor memory device

Abstract: A semiconductor memory device is operable in normal and test operation modes. At the test operation, in response to a first active command, a row address signal that is input from the outside is captured in the row decoder, and in response to a first write/read command, a column address signal input from the outside is captured in the column decoder. At this time, a word line and a bit line are not selected. Thereafter, in response to a second active command, a word line corresponding to the row address signal is selected in the row decoder, and, in response to a second write/read command, a bit line that corresponds to the column address signal is selected in the column decoder. The time period from the time at which the second read/write command is input to the time at which the second active command is input, is measured as tRCD.

Inventors: Inaba; Hideo (Tokyo, JP)

Assignee: Elpida Memory, Inc.

International Classification: G11C 7/00 (20060101); G11C 8/00 (20060101)

Expiration Date: 2020-01-03 0:00:00