| 摘要 |
On-die termination circuit of a semiconductor memory apparatus is provided to improve performance of the semiconductor memory apparatus by performing data input and data output normally by changing a code value used for preventing a code calibration error in correspondence to PVT(Process/Voltage/Temperature) variation. A comparison part(20,50) outputs a comparison result signal by comparing a voltage corresponding to a normal code with a reference voltage. A code calibration part(200,600) changes the normal code according to the comparison result signal, and resets the normal code as a reset code or a variable fuse code according to a reset signal. The code calibration part comprises a code setting unit and a register(400,800). The code setting unit sets a fuse code and outputs a fuse code enable signal to define the usage of the fuse code. The register counts and stores the normal code according to the comparison result signal, and resets the normal code by selecting one of the reset code or the fuse code according to the reset signal and the fuse code enable signal.
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