| 摘要 |
PROBLEM TO BE SOLVED: To make the amplitude of an analog output voltage large and to improve the linearity. SOLUTION: This D/A converter is equipped with (k) positive plus-side current cells CP1 to CPk, each using a PMOS transistor(TR) MN1 for a constant current source which inputs a bias voltage VBP at its gate electrode, (k) negative-side current cells CN1 to CNk, each using an NMOS TR MN1 for the constant current source which inputs a bias voltage VBN at its gate electrode, an output operational amplifier OP1 provided with a feedback resistance R1, plus-side dummy current cells SCP1 to SCPk as positive-side current cells which are normally on, and an operational amplifier OP2 for constant current compensation which supplies the bias voltage VBN, and the operational amplifier OP2 controls the bias voltage VBN so that the constant current IP of the plus-side current cells CP and the constant current IN of the negative-side current cells CN are equal to each other.
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