DDR SGRAM

摘要

PURPOSE: A double data rate synchronous graphic RAM is provided which simultaneously performs read and write operations in synchronization with an external clock signal having two opposite phases to improve the performance of system. CONSTITUTION: A synchronous graphic RAM performs one command for two external clocks to write data in a bank and senses the data through a sense amplifier to output the sensed data to an output buffer(9). The synchronous graphic RAM includes a DLL(21) for generating a reference clock when the data are read to apply the reference clock to the output buffer, a strobe generator(22) for receiving an external control signal to generate a strobe signal and applying the strobe signal to the output buffer, and a pre-fetch(20) located between the sense amplifier and the output buffer to previously fetch data of an address corresponding to an address to be fetched in advance through the sense amplifier to store the data in a queue.