摘要 |
A common bias section is composed of a first series circuit having an internal resistor and an external resistor connected in series and an operational amplifier having a first input terminal connected to a reference voltage, a second input terminal connected to a Vr1 node, and an output terminal connected to the series circuit. An impedance trimming section is composed of a series circuit having an internal resistor and an impedance dummy resistor connected in series, a comparator CMP having a first input terminal connected to the Vr1 node and a second input terminal connected to a Vto1 node, a code control circuit which uses a clock signal to latch an output signal from the comparator to generate a plurality of switching codes, and a switching circuit which switch a resistance value of the impedance dummy resistor.
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