CPC G11C 7/1051 (2013.01) [H03K 19/0005 (2013.01); G11C 2207/2254 (2013.01)] | 20 Claims |
1. An apparatus comprising:
an input/output (I/O) circuit connected to a signal pin, the I/O circuit including a strong driver circuit and a weak driver circuit, wherein the strong driver circuit is stronger than the weak driver circuit;
an impedance control (ZQ) calibration circuit connected to a ZQ pin, and configured to perform ZQ calibration using a sweep code or a fixed code, the ZQ pin being connected to a ZQ resistor, the sweep code being updated in a calibration operation related to the ZQ pin, and the fixed code being stored in a register; and
a ZQ calibration control circuit connected to the I/O circuit and the ZQ calibration circuit, and configured to:
generate a ZQ calibration code signal according to ZQ calibration conditions, based on the sweep code or the fixed code,
select a driver circuit from among the strong driver circuit and the weak driver circuit based on the ZQ calibration conditions,
adjust a termination resistance of the signal pin by providing a ZQ calibration code related to the sweep code to the selected driver circuit, and
provide a ZQ calibration code related to the fixed code to an unselected circuit from among the strong driver circuit and the weak driver circuit.
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