Semiconductor integrated circuit, variable gain amplifier, and sensing system

A semiconductor integrated circuit comprising:

• a first pad provided on one end side of a first resistive element and one end side of a second resistive element and one end side of a fourth resistive element and one end side of a fifth resistive element externally provided;
• a second pad provided on a different end side of the first resistive element;
• a third pad provided on a different end side of the second resistive element and one end side of a third resistive element externally provided;
• a fourth pad provided on a different end side of the fourth resistive element;
• a fifth pad provided on a different end side of the fifth resistive element and one end side of a sixth resistive element externally provided;
• an operation amplifier;
• a first signal line wired between an output terminal of the operation amplifier and the first pad;
• a second signal line wired between an inverting input terminal of the operation amplifier and the second pad;
• a third signal line wired between the inverting input terminal of the operational amplifier and the third pad;
• a fifth signal line wired between the inverting input terminal of the operational amplifier and the fourth pad;
• a sixth signal line wired between the inverting input terminal of the operational amplifier and the fifth pad;
• a first ESD (Electrostatic Discharge) protection element provided to the first signal line;
• a fourth signal line, through which a voltage signal of the first pad is transmitted, the fourth signal line being connected to the first pad,
• a first switch provided on the first signal line;
• a second switch provided on the second signal line;
• a third switch provided on the third signal line;
• a fourth switch provided on the fifth signal line;
• and
• a fifth switch provided on the sixth signal line,
• wherein a reference voltage is supplied to a non-inverting input terminal of the operation amplifier.