An oscillator includes a package having a first side, a second side, a third side, and a fourth side, a resonator and an oscillation circuit disposed in the package, an output terminal arranged along the first side of the package, and outputting a clock signal generated by the oscillation circuit, and a control terminal arranged along the second side of the package, and supplied with a digital control signal adapted to update an operation state of the oscillation circuit.

An oscillator includes a package having a first side, a second side, a third side, and a fourth side, a resonator and an oscillation circuit disposed in the package, an output terminal arranged along the first side of the package, and outputting a clock signal generated by the oscillation circuit, and a control terminal arranged along the second side of the package, and supplied with a digital control signal adapted to update an operation state of the oscillation circuit.

An integrated circuit includes an input pad and a Schmitt trigger coupled to the input pad. The Schmitt trigger includes a first inverter and a second inverter. The Schmitt trigger includes a pull-up transistor coupled to an input of the second inverter and configure to supply a high reference voltage to the input of the second inverter.

A circuit device includes a DLL circuit and an adjustment circuit. The DLL circuit has a plurality of delay elements, and a first clock signal generated using a first resonator and having a first clock frequency is input to the DLL circuit. Delayed clock signals from the delay elements of the DLL circuit, and a second clock signal generated using a second resonator and having a second clock frequency lower than the first clock frequency are input to the adjustment circuit, and the adjustment circuit adjusts delay amounts of the delay elements of the DLL circuit using a frequency difference between the first clock frequency and the second clock frequency.

A Schmitt trigger circuit according to an embodiment includes a voltage dividing circuit that divides an input voltage and outputs a divided voltage, and a basic Schmitt trigger circuit that includes a transistor as a current controlling element and controls current flowing through a light emitting diode (LED) included in an external photocoupler on the basis of the output voltage of the voltage dividing circuit proportional to the input voltage. The voltage dividing circuit has a positive temperature coefficient.

An oscillator includes a package having a first side, a second side, a third side, and a fourth side, a resonator and an oscillation circuit disposed in the package, an output terminal arranged along the first side of the package, and outputting a clock signal generated by the oscillation circuit, and a control terminal arranged along the second side of the package, and supplied with a digital control signal adapted to update an operation state of the oscillation circuit.

An integrated circuit includes an input pad and a Schmitt trigger coupled to the input pad. The Schmitt trigger includes a first inverter and a second inverter. The Schmitt trigger includes a pull-up transistor coupled to an input of the second inverter and configure to supply a high reference voltage to the input of the second inverter.