| 摘要 |
Provided is an output impedance circuit, which has a constant output impedance regardless of a pad voltage, and an output buffer circuit including the output impedance circuit. The output impedance circuit includes an output stage and an impedance control stage. The output stage outputs a current corresponding to a DC bias voltage via an output terminal, and the impedance control stage controls the current flowing through the output stage in response to an output signal. The output stage includes a resistance component and a first MOS transistor. A first terminal of the resistance component is connected to the output terminal. A first terminal of the first MOS transistor is connected to a second terminal of the resistance component, a second terminal of the first MOS transistor is connected to a voltage source, and an input signal is input to a gate of the first MOS transistor.
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