| 摘要 |
PROBLEM TO BE SOLVED: To provide a D/A converter circuit with satisfactory linearity of output voltage with respect to a received digital value in spite of a comparatively low cost and to correct the span of a pressure sensor circuit by using the D/A converter circuit with high accuracy. SOLUTION: A constant current circuit is configured with operational amplifiers OP1, OP2, MOSFETs Q1, Q2, Q3, Q4, Q5 and an R-2R ladder circuit 1. Thus, a current in response to a digital value received by the R-2R ladder circuit 1 can be extracted for the constant current circuit. A drain current of the MOSFET Q5 is given to a current-voltage conversion circuit 4, which outputs a voltage in response to the digital value received.
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