| 摘要 |
PROBLEM TO BE SOLVED: To reduce the area occupied by transistors(TRs) in a D/A converter circuit. SOLUTION: The D/A converter circuit is provided with 2-input circuits 50-53 that select either of two inputs in response to higher-order 1-bit complementary selection signals D2, *D2 among 3-bit selection signals and with a 4-input selection circuit 24X that selects one of four inputs in response to lower-order 2-bit complementary selection signals D1, *D1, D0 and *D0. In each of the 2-input selection circuit 50-53, the electrodes of two TRs are connected in common on one side and both TRs are laid out on the same row and adjacent to each other, and the 4-input selection circuit 24X has hour analog switch circuits each having two TRs connected in series and placed on the same row, where the analog switch circuits are connected in parallel and each is placed on the same row of the corresponding 2-input selection circuit. Optionally, the 4-input selection circuit may be provided with three 2-input selection circuits that are laid out in a tree form.
|
