| 摘要 |
PURPOSE:To trim resistance even after an integrated circuit has been assembled in a package or the like by a method wherein semiconductor switches are connected, in series or in parallel, to all the resistors in a resistance circuit network or a part of the resistors and, at the same time, a memory device to control the switching operation of these semiconductor switches is installed. CONSTITUTION:When semiconductor switches 15, 16 are set to the OFF state, the resistance value between terminals 17 and 18 becomes equal to the resistance value R11 of a resistor 11; when only the semiconductor switch 15 is set to the ON state, the resistance value between the terminals 17 and 18 becomes the parallel composite resistance value which is composed of the resistance value of a resistor 12 and the resistance value of the semiconductor switch 15 set to the ON state. Accordingly, the resistance value between the terminals 17 and 18 depends on which semiconductor switch is set to the ON or OFF state. As a result, which semiconductor switch is to be set to the ON or OFF state is decided by an instruction from a control terminal 22 of a control circuit 20. This circuit is constructed by combining the semiconductor switch with a memory device; as a result, it is easy to trim the resistance.
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