| 摘要 |
PROBLEM TO BE SOLVED: To improve yield even when unexpected fluctuation exists in a process condition by providing plural constant current transistors, connecting these plural transistor in parallel and selecting a prescribed transistor from plural transistors. SOLUTION: Plural constant current transistors 2, 3, 4 are connected in parallel, and the prescribed transistor is selected from plural transistors 2, 3, 4 by selection circuits 5, 5a, 5b. When a reset signal 13 is set in L level first beforehand, a switching transistor 9 goes to the on-state, and the transistors 2, 3, 4 goes to the off-state in the selection circuits 5, 5a, 5b. When the reset signal 13 is released, and a terminal 12 of a NAND gate 15 is made to H level, the transistors 2, 3, 4 goes to the on-state. For obtaining prescribed performance, when the fuse circuit 8 of the selection circuit 5 is cut out, the transistor connected to the selection circuit is on/off controlled, and a response speed of a DRAM input circuit is adjusted.
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