Semiconductor integrated circuit and noncontact information system including it

The present invention extends the reading range between a contactless type information medium (semiconductor integrated circuit) and a reader/writer, which exchanges data in contactless communications with the contactless type information medium, and enables a stable data exchange even if the power supply voltage is lowered when data is returned from the contactless type information medium to the reader/writer. Specifically, when data is returned from the contactless type information medium, the data to be returned is held in the logic circuit section 200 capable of operating at a lower voltage than the non-volatile memory circuit section 300 , and the reset detection lower limit voltage to be used by the reset generating circuit 160 during the data-returning period is set to be lower than that during periods other than the data-returning period.