SEMICONDUCTOR MEMORY DEVICE HAVING REFRESH CHARACTERISTICS VARIABLE ACCORDING TO OPERATION MODE, IN WHICH PRECHARGE VOLTAGE IS SET LOWER THAN NORMAL OPERATION MODE AT REFRESH MODE

摘要

PURPOSE: A semiconductor memory device having refresh characteristics variable according to an operation mode is provided, which reduces current consumption during a self refresh operation and varies a bit line precharge voltage according to its operation mode. CONSTITUTION: A plurality of memory cells have word lines and bit lines arranged in a matrix. A precharge voltage generator circuit(140) receives a reference voltage and generates the first precharge voltage and the second precharge voltage lower than the first precharge voltage. A switch circuit(150) selects the first and the second precharge voltages in response to selection signals indicating operation modes. And a precharge circuit precharges the bit lines with a voltage selected by the switch circuit.