| 摘要 |
PURPOSE:To save power consumption with a reduction in the number of terminals by inputting two kinds of signals different in the voltage value from a common input terminal to set two kinds of modes. CONSTITUTION:An integrated circuit is composed of a terminal Common concurrently serving for normal input logical computation and the generation of test mode, a normal input logic terminal I2, normal input logic getes 11 and 12, a test mode generation circuit 13 and NOR gates 15 and 16. When a signal within the logic amplitude range of 0 - power source voltage (+VCC) is applied to the terminal Common, the output of the test mode generation circuit 13 moves to '0' level, at which terminals T1 and T2 of the NOR gates 15 and 16 transmit the normal input logic. Then, when a signal exceeding the power source voltage (+VCC) is applied, the output of the test mode generation circuit 13 exceeds the input logic threshold of the NOR gates 15 and 16 to enter the test mode. This enables switching between the normal input logical computation and the generation of test mode with one common terminal Common.
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