METHOD AND APPARATUS HAVING ENHANCED OSCILLATOR PHASE NOISE USING HIGH Vt MOS DEVICES

Abstract

A voltage-controlled oscillator (VCO), includes a resonator circuit connected to receive an input voltage and having a first output node and a second output node; and at least one cross-coupled switching circuit portion, each cross-coupled switching circuit portion comprising a first transistor having a drain connected to the first output node and a second transistor having a drain connected to the second output node, the first transistor having a gate connected between the drain of the second transistor and the second output node and the second transistor having a gate connected between the drain of the first transistor and the first output node, each of the first and second transistors having a threshold voltage that is determined to be the highest threshold voltage available for the process used to create the VCO.

1 . A voltage-controlled oscillator (VCO), comprising:
 a resonator circuit connected to receive an input voltage and having a first output node and a second output node; and   at least one cross-coupled switching circuit portion, each cross-coupled switching circuit portion comprising a first transistor having a drain connected to the first output node and a second transistor having a drain connected to the second output node, the first transistor having a gate connected between the drain of the second transistor and the second output node and the second transistor having a gate connected between the drain of the first transistor and the first output node, each of the first and second transistors having a gate oxide thickness of at least 55 Angstroms, wherein a magnitude of a threshold voltage for each of the first and second transistors is greater than or equal to one volt.   
     
     
         2 . The VCO as recited in  claim 1 , wherein the resonator circuit comprises at least one inductor circuit and at least one capacitor circuit, a first terminal of the at least one inductor circuit and a first terminal of the at least one capacitor circuit being connected in common to the first output node and a second terminal of the at least one inductor circuit and a second terminal of the at least one capacitor circuit being connected in common to the second output node. 
     
     
         3 . The VCO as recited in  claim 2 , wherein the resonator circuit comprises a multiport inductor. 
     
     
         4 . The VCO as recited in  claim 1 , wherein the first and second transistors are, respectively, first and second NMOS transistors, each of said first and second NMOS transistors having a source connected to a lower voltage rail. 
     
     
         5 . The VCO as recited in  claim 1 , wherein the first and second transistors are, respectively, first and second PMOS transistors, each of said first and second PMOS transistors having a source connected to an upper voltage rail. 
     
     
         6 . The VCO as recited in  claim 1 , wherein the at least one cross-coupled switching circuit portion comprises a first cross-coupled switching circuit portion comprising first and second PMOS transistors, each of said first and second PMOS transistors having a source connected to an upper voltage rail, and a second cross-coupled switching circuit portion comprising first and second NMOS transistors, each of said first and second NMOS transistors having a source connected to an lower voltage rail. 
     
     
         7 . A voltage-controlled oscillator (VCO), comprising:
 a resonator circuit connected to receive an input voltage and having a first output node and a second output node; and   at least one cross-coupled switching circuit portion, each cross-coupled switching circuit portion comprising a first transistor having a drain connected to the first output node and a second transistor having a drain connected to the second output node, the first transistor having a gate connected between the drain of the second transistor and the second output node and the second transistor having a gate connected between the drain of the first transistor and the first output node, each of the first and second transistors having a gate oxide thickness of at least 55 Angstroms.   
     
     
         8 . The VCO as recited in  claim 7 , wherein the resonator circuit comprises at least one inductor circuit and at least one capacitor circuit, a first terminal of the at least one inductor circuit and a first terminal of the at least one capacitor circuit being connected in common to the first output node and a second terminal of the at least one inductor circuit and a second terminal of the at least one capacitor circuit being connected in common to the second output node. 
     
     
         9 . The VCO as recited in  claim 8 , wherein the resonator circuit comprises a multiport inductor. 
     
     
         10 . The VCO as recited in  claim 7 , wherein the first and second transistors are, respectively, first and second NMOS transistors, each of said first and second NMOS transistors having a source connected to a lower voltage rail. 
     
     
         11 . The VCO as recited in  claim 7 , wherein the first and second transistors are, respectively, first and second PMOS transistors, each of said first and second PMOS transistors having a source connected to an upper voltage rail. 
     
     
         12 . The VCO as recited in  claim 7 , wherein the at least one cross-coupled switching circuit portion comprises a first cross-coupled switching circuit portion comprising first and second PMOS transistors, each of said first and second PMOS transistors having a source connected to an upper voltage rail, and a second cross-coupled switching circuit portion comprising first and second NMOS transistors, each of said first and second NMOS transistors having a source connected to an lower voltage rail. 
     
     
         13 . A voltage-controlled oscillator (VCO), comprising:
 a resonator circuit connected to receive an input voltage and having a first output node and a second output node; and   at least one cross-coupled switching circuit portion, each cross-coupled switching circuit portion comprising a first transistor having a drain connected to the first output node and a second transistor having a drain connected to the second output node, the first transistor having a gate connected between the drain of the second transistor and the second output node and the second transistor having a gate connected between the drain of the first transistor and the first output node, wherein a magnitude of a threshold voltage for each of the first and second transistors is greater than or equal to one volt.   
     
     
         14 . The VCO as recited in  claim 13 , wherein the resonator circuit comprises at least one inductor circuit and at least one capacitor circuit, a first terminal of the at least one inductor circuit and a first terminal of the at least one capacitor circuit being connected in common to the first output node and a second terminal of the at least one inductor circuit and a second terminal of the at least one capacitor circuit being connected in common to the second output node. 
     
     
         15 . The VCO as recited in  claim 14 , wherein the resonator circuit comprises a multiport inductor. 
     
     
         16 . The VCO as recited in  claim 13 , wherein the first and second transistors are, respectively, first and second NMOS transistors, each of said first and second NMOS transistors having a source connected to a lower voltage rail. 
     
     
         17 . The VCO as recited in  claim 13 , wherein the first and second transistors are, respectively, first and second PMOS transistors, each of said first and second PMOS transistors having a source connected to an upper voltage rail. 
     
     
         18 . The VCO as recited in  claim 13 , wherein the at least one cross-coupled switching circuit portion comprises a first cross-coupled switching circuit portion comprising first and second PMOS transistors, each of said first and second PMOS transistors having a source connected to an upper voltage rail, and a second cross-coupled switching circuit portion comprising first and second NMOS transistors, each of said first and second NMOS transistors having a source connected to an lower voltage rail.