Semiconductor device

摘要

A device, comprising an output terminal; an output circuit coupled to the output terminal and having an adjustable impedance; and an impedance adjustment circuit adjusting stepwise the adjustable impedance so as to head toward a first reference impedance. The impedance adjustment circuit changes the adjustable impedance by a first amount when the adjustable impedance is within a first range, and changes the adjustable impedance by a second amount when the adjustable impedance is out of the first range. The first amount is smaller than the second amount.

主权项

1. A device comprising:
an output terminal; a first output circuit connected to the output terminal and being indicative of a first impedance; and an impedance adjustment circuit including:
a first terminal,a first replica circuit coupled to the first terminal and being indicative of an first replica impedance,a reference voltage generation circuit generating a plurality of reference voltages that are different in potential level from each other,a plurality of first comparator circuits each including first and second input nodes, the first input node of each of the first comparator circuits being coupled to the first terminal, the second input node of each of the first comparator circuits receiving an associated one of the reference voltages, the first comparator circuits outputting a plurality of first comparison result signals, anda first adjustment signal generation circuit receiving the first comparison result signals, generating first impedance adjustment signals and supplying the first impedance adjustment signals to the first output buffer and the first replica circuit,the first output buffer changing the first impedance in response to the first impedance adjustment signals, and the first replica circuit changing the first replica impedance in response to the first impedance adjustment signals.