| 摘要 |
PURPOSE:To eliminate an unstable state of an output voltage irrespective of an input voltage by a method wherein both a second P-channel MOSFET and a second N-channel MOSFET are constituted by a MOSFET of the buried channel type. CONSTITUTION:To take an N-MOSFET as an example, 0 V is impressed on a source wiring part 303; a drain voltage of +VDD is impressed on a drain wiring part 305; a gate voltage of +VGS is impressed on a gate electrode 304; as a result, a channel region 308 is inverted to an N-type; a drain current flows between a source 306 and a drain 309. When the gate voltage is lowered gradually, an inversion layer of the channel region 306 disappears, but a buried N-type layer 308 remains in an N-type state as it is; therefore, the drain current does not become 0. Accordingly, even when +VDD or 0 V is impressed on an input terminal of an inverter circuit for an analog value, a second P-MOSFET and a second N-MOSFET are not shut off completely; their output terminals are not shut off from a positive power supply and a negative power supply in the same manner; an output voltage of the inverter circuit for the analog value is kept stable.
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