| 摘要 |
A semiconductor memory device capable of adjusting impedance of a data input/output driver is provided to set and supply termination resistance rapidly in correspondence to the variation of input-resistance according to the variation of PVT(Process, Voltage and Temperature) within a limited time. A reference range supply unit(200) provides a normal target range corresponding to a resistance value of a ZQ resistor, and outputs a fine target range in response to a fine driving signal. A termination resistance supply unit(400) provides an output resistance value corresponding to a plurality of control codes. A control code generation unit(300) generates the plurality of control codes in order for the output resistance value to be located within the normal target range, and controls the output resistance value to be located within the fine target range by controlling the plurality of code signals in response to the fine driving signal. A normal adjustment sensing unit(500) generates the fine driving signal by sensing that the output resistance value is located within the normal target range.
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