| 摘要 |
PURPOSE:To enable output of a logic input circuit to be stable by connecting the connection position of a pull-up resistor or a pull-down resistor to the input terminal side of series resistor between a logic inverter and a logic signal input terminal and then by constituting it with resistors which are less affected by fluctuation of environmental conditions. CONSTITUTION:A logic signal input terminal 11, a series resistor for solving surge R1, a pull-tip resistor R2, diodes D1 to D2 for solving latch-up, and logic inverters U1 to U3 are provided. Then, the resistors R1 and R2 consist of an oxide film and polysilicon, respectively. are not affected by environmental conditions such as temperature and supplied power supply voltage and have a stable resistance, and then the pull-up resistor R2 is connected to the input terminal side of the series resistor R1. Thus, a signal which is not divided by the resistor R1 and the series resistor R1 is fed to an input terminal 12 of the logic inverter U1. Then, as far as voltage (logic) ai the logic signal input terminal 11 does not fluctuate, voltage (logic) at the input terminal 12 of the logic inverter U1 does not fluctuate. it allows a stable logic output to be obtained in response to input logic in logic input circuit of LSI. |
