System and method for reducing effects of switched capacitor kickback noise

1. A circuit, comprising:

a first input terminal;

a first transmission line;

a first sampling switch coupled to the first input terminal through the first transmission line;

a first sampling capacitor coupled to the sampling switch; and

a first open-circuit quarter wavelength stub coupled to the first transmission line, the first open-circuit quarter wavelength stub configured to reduce kickback noise on the first transmission line, wherein a length of the first open-circuit quarter wavelength stub is tuned to a first frequency associated with the kickback noise on the first transmission line.

2. The circuit of claim 1 , wherein the first open-circuit quarter wavelength stub is configured to filter the first frequency associated with the kickback noise on the first transmission line.

3. The circuit of claim 1 , wherein the first open-circuit quarter wavelength stub is transparent to an input signal from the first input terminal.

4. The circuit of claim 1 , further comprising one or more additional open-circuit quarter wavelength stubs coupled to the first transmission line.

5. The circuit of claim 4 , wherein a length of each of the one or more additional open-circuit quarter wavelength stubs is tuned to a respective frequency associated with the kickback noise on the first transmission line.

6. The circuit in claim 1 , wherein the circuit further comprises:

a second input terminal;

a second transmission line;

a second sampling switch coupled to the second input terminal through the second transmission line;

a second sampling capacitor coupled to the second sampling switch; and

a second open-circuit quarter wavelength stub coupled to the second transmission line.

7. The circuit in claim 6 , wherein the first and second input terminals, the first and second transmission lines, the first and second sampling switches, and the first and second sampling capacitors are parts of a differential circuit.

8. The circuit in claim 6 , wherein:

a length of the second open-circuit quarter wavelength stub is tuned to a second frequency associated with kickback noise on the second transmission line.

9. The circuit in claim 6 , wherein the first and second open-circuit quarter wavelength stubs have similar lengths.

10. The circuit in claim 6 , further comprising:

a first set of one or more additional open-circuit quarter wavelength stubs coupled to the first transmission line; and

a second set of one or more additional open-circuit quarter wavelength stubs coupled to the second transmission line.

11. The circuit in claim 10 , wherein:

a length of each of the one or more additional open-circuit quarter wavelength stubs in the first set is tuned to a respective frequency associated with the kickback noise on the first transmission line; and

a length of each of the one or more additional open-circuit quarter wavelength stubs in the second set is tuned to a respective frequency associated with kickback noise on the second transmission line.

12. A circuit, comprising:

a first input terminal;

a first transmission line;

a first sampling switch coupled to the first input terminal through the first transmission line, wherein the sampling switch comprises an NMOS gate;

a first sampling capacitor coupled to the sampling switch; and

a first open-circuit quarter wavelength stub coupled to the first transmission line, the first open-circuit quarter wavelength stub configured to reduce kickback noise on the first transmission line.

13. A method for reducing kickback noise in a circuit, comprising:

determining a frequency associated with a kickback noise on a first transmission line of the circuit, the circuit having an input terminal coupled to the first transmission line;

configuring a length of an open-circuit quarter wavelength stub to correspond to the determined frequency; and

coupling the open-circuit quarter wavelength stub to the first transmission line to filter the frequency associated with the kickback noise, wherein the kickback noise is resulted from opening a sampling switch in the circuit.

14. The method of claim 13 , wherein the open-circuit quarter wavelength stub is transparent to an input signal from the input terminal.

15. The method of claim 13 , further comprising determining an additional frequency associated with the kickback noise on the first transmission line.

16. The method of claim 15 , further comprising:

configuring a length of an additional quarter wavelength stub to correspond to the additional frequency associated with the kickback noise on the first transmission line; and

coupling the additional open-circuit quarter wavelength stub to the first transmission line to filter the additional frequency associated with the kickback noise on the first transmission line.

17. The method of claim 13 , further comprising:

determining a frequency associated with a kickback noise on a second transmission line of the circuit;

configuring a length of a first additional open-circuit quarter wavelength stub to correspond to the determined frequency associated with the kickback noise on the second transmission line; and

coupling the first additional open-circuit quarter wavelength stub to the second transmission line to filter the frequency associated with the kickback noise on the second transmission line.

18. The method of claim 17 , further comprising:

determining an additional frequency associated with the kickback noise on the first transmission line;

configuring a length of a second additional open-circuit quarter wavelength stub to correspond with the additional frequency associated with the kickback noise on the first transmission line; and

coupling the second additional open-circuit quarter wavelength stub to the first transmission line to filter the additional frequency associated with the kickback noise on the first transmission line.