Semiconductor integrated circuit with analogue signal processing circuit and digital signal processing circuit formed on single semiconductor substrate

摘要

A semiconductor integrated circuit device having an analogue signal processing circuit and a digital signal processing circuit formed on a single semiconductor substrate is disclosed. As an example of the analogue signal processing circuit, a voltage comparator is described. Being liable to be affected by noise, an inverter 2 is formed of an NMOS transistor 41 and a resistance R. For transistor 41 is formed in a well region having a conductivity type (p) opposite to the conductivity type of the substrate (n), it is not easily influenced by noise transmitted through the substrate. Therefore, a voltage comparator independent of the adverse effect of noise from the digital signal processing circuit is obtained.