AMPLIFICATION DEVICE

摘要

Provided is an amplification device in which an input impedance is set to several GO to several tens of 10GO and the ESD resistance is improved. An ECM is connected to an input terminal (21). The frequency characteristic is made flat up to the voice band by a high input impedance of a CMOS amplifier (20) and the input impedance is set to several GO to several tens of 10GO so as to realize a desired electric characteristic by increasing the response speed after the power supply to the ECM and after the large sound detection. By connecting a P-channel MOS transistor (27) and a N-channel MOS transistor (28) as ESD protection elements, it is possible to constitute a path for letting out a serge voltage generated outside an IC during assembling and coming from the input terminal (21) to a power supply terminal or a grounding terminal without affecting the signal (20 Hz to 20 kHz) of the sound band coming from the input terminal (21).