| 摘要 |
PURPOSE:To improve the linearity around the middle of a D/A converter by providing a switch means connecting/disconnecting selectively a path to an input terminal of an adder circuit from an output terminal of a reference output circuit with an output of a digital input signal control circuit. CONSTITUTION:Since the linearity when a digital input signal deteriorating most the linearity of the D/A converter changes from (01111111) to (10000000) is obtained from a D/A conversion output fixed to a high-order 5-bit of a reference output circuit 600 outputting an analog value and an element D/A converter 300 corresponding to the 4-th bit from the least significant digit, the output of the reference output circuit 600 is made equal to that of the 4-th bit from the least significant digit of the element D/A converter 300 to attain the linearity around the middle of the D/A conversion, and the accuracy of the output of the circuit 600 is kept within 1/2 of the output of the least significant bit, then the linearity at the middle of the D/A converter is ensured sufficiently.
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