Patent ID: 8120978
Filing Date: 2012-02-21
Classification: G11C

Abstract:
1. A semiconductor memory device having an auto-precharge function of automatically resetting a word line and of precharging a bit line after ending a read operation or a write operation, the semiconductor memory device comprising: first and second clock generation circuits that generate first and second internal clocks, respectively; a first counter circuit that counts at least latency indicating number of clocks since issuance of a read command until an output of read data or number of clocks since issuance of a write command until an input of write data, synchronously with the first internal clock; and a second counter circuit that counts at least a write recovery period since completion of an output of the read data or completion of an input of the write data until start of auto-precharge, synchronously with the second internal clock, wherein the second clock generation circuit activates the second internal clock when the auto-precharge is designated at time of issuance of the read command or the write command, and deactivates the second internal clock when the auto-precharge is not designated at the time of issuance of the read command or the write command.