| 摘要 |
PURPOSE:To facilitate improvement in operation speed, integration density and power consumption of an integrated circuit, by forming two integrated circuit parts on a semiconductor substrate in an electrically isolated state, and differentiating the operating power-source voltages of the circuit parts. CONSTITUTION:Circuit parts 1 and 2 are electrically isolated by a p-type silicon semiconductor substrate 10 and a p-type isolating diffused layer 2 in a constitution wherein an n-type epitaxial layer 11 is surrounded. In the circuit part 2, which is operated with a high power-source voltage Vcc, CMOS transistors M1 and M2, whose withstanding voltage is high, are formed. Meanwhile, in the circuit part 1, which is operated by a lower power-source voltage Vdd (Vdd<Vcc), CMOS transistors M3 and M4, whose withstanding voltage is low but which are machined minutely, are formed at a high density. An interface 3 is formed so as to perform level exchange of signals between the two circuit parts 1 and 2. The interface is formed by using the CMOS transistors M1 and M2 on the side of the peripheral circuit part 2. The level of the logic signal, which is amplified close to the high power-source voltage Vcc, and the level of the logic signal, which is amplified at less than the low voltage Vdd, are converted. |
