SEMICONDUCTOR MEMORY DEVICE AND MEMORY SYSTEM USING IT

摘要

PROBLEM TO BE SOLVED: To provide a semiconductor memory device dissolving problems that power consumption due to a continuously operating clock in a synchronous DRAM, shortage of a setup time and a hold time for a high speed clock, increase in power consumption and a layout area due to use of a PLL and a DLL (delay locked loop). SOLUTION: An address (and input data) with sufficient setup and hold times such as an asynchronous system are inputted. Then, when the device becomes a data output possible state, a high speed oscillator with built-in a memory operates according to a control signalϕOSCi showing output operation to generate a reference signal DATA OUT, and the data DQ to the outside of a chip are outputted synchronized with the reference signal DATA OUT. This reference signal DATA OUT is outputted together with the data, and is used when an external system fetches the output data DQ.