Oscillator circuit and integrated circuit for oscillation

An oscillator circuit comprising:

• an amplifier portion comprising at least a first, a second, and a third CMOS inverters connected in cascade, said CMOS inverters having gate areas that decrease successively from said first to a last inverter in said amplifier portion, said amplifier portion further comprising an input terminal and an output terminal, and each of said CMOS inverters further comprising an input terminal and an output terminal;
• a filter circuit comprising a capacitive element and a resistor, said capacitive element and said resistor being connected between an input terminal and an output terminal of said first CMOS inverter, said capacitive element having one terminal connected with said input terminal of said first CMOS inverter and having another terminal acting as said input terminal of said amplifier portion;
• a piezoelectric oscillator connected between said input terminal and said output terminal of said amplifier portion;
• a feedback resistor connected between said input terminal and said output terminal of said amplifier portion;
• a first load capacitance connected between said input terminal of said amplifier portion and a terminal at a certain potential;
• and
• a second load capacitance connected between said output terminal of said amplifier portion and said terminal at said certain potential.

An integrated circuit for oscillation comprising;

• an amplifier portion comprising an input terminal, an output terminal, a plurality of CMOS inverters connected in cascade and a filter circuit;
• a feedback resistor connected between said input terminal and said output terminal of said amplifier portion;
• a first load capacitance connected between said input terminal of said amplifier portion and a terminal at a certain potential;
• a second load capacitance connected between said output terminal of said amplifier portion and said terminal at said certain potential;
• wherein said CMOS inverters have gate areas, said gate areas decreasing successively from a first CMOS inverter to a last CMOS inverter of said plurality of CMOS inverters connected in cascade, and wherein said input terminal and said output terminal of said amplifier portion are for receiving signals from an oscillator to perform an oscillation operation.

An integrated circuit for oscillation comprising:

• an amplifier portion consisting of at least a first, a second, and a third CMOS inverters connected in cascade, said CMOS inverters having gate areas that decrease successively from said first to a last inverter in said amplifier potion, said amplifier portion further comprising an input terminal and an output terminal, and each of said CMOS inverters further comprising an input terminal and an output terminal;
• a filter circuit consisting of a capacitive element and a resistor, said capacitive element and said resistor being connected between an input terminal and an output terminal of said first CMOS inverter, said capacitive element having one terminal connected with said input terminal of said first CMOS inverter and having another terminal acting as said input terminal of said amplifier portion;
• a feedback resistor connected between said input terminal and said output terminal of said amplifier portion;
• a first load capacitance connected between said input terminal of the amplifier portion and a terminal at a certain potential;
• and
• a second load capacitance connected between said output terminal of said amplifier portion and said terminal at said certain potential;
• wherein said input terminal and said output terminal of said amplifier portion are for receiving signals from an oscillator to perform an oscillation operation.