| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent inversion of an output by setting a dispersion range of capacitance of a plurality of capacitors used for the D/A converter within a prescribed value. SOLUTION: The designed capacitance of a plurality of capacitors C1-C6 for the D/A converter is selected according to the equation: Coj-dCj>Σ(ij) (Coj+ dCj) (for-all-j), where Ci, Cj are capacitance of i-th and j-th capacitors, Coi, Coj are designed capacitance of i-th and j-th capacitors, dCi, dCj are dispersion in capacitcance of i-th and j-th capacitors,Σ(ij) is total sum of the capacitance of the capacitors as to all numbers i smaller than a number j, and (for-all-j) is the modification of the equation that the equation is to be satisfied with all numbers i. In this D/A converter 20, even when a capacitance ratio of a plurality of the weight capacitors is in dispersion under the worst condition, the capacitance of the j-th capacitor is larger than the sum of the capacitance sets of all the capacitors from the 1st to the (j-1)th without fail thereby avoiding inversion in the output of the D/A converter.</p> |
