SYSTEMS AND METHODS FOR ACTIVE CANCELLATION FOR IMPROVING ISOLATION OF TRANSMISSION GATES IN HIGH-FREQUENCY ANALOG TO DIGITAL CONVERTERS

摘要

An active cancellation system may provide a first and second transmission gates that are fed with an input signal and a complimentary signal, respectively. The first transmission gate may be switched on/off, and a second transmission gate may remain off at all times. When switched off, the first transmission gate may provide a leakage signal resulting from leakage in current, especially at high input frequencies, which is detrimental to performance. The complimentary signal fed to the second transmission gate is out of phase with the input signal, but identical in amplitude. Thus, second transmission gate may output a signal that can cancel out the leakage signal from the first transmission gate.

主权项

1. A method for active cancellation for an analog to digital converter (ADC), the method comprising:
receiving an input signal by the ADC and generating a differential pair, wherein the differential pair comprises the input signal and a negative signal, which is a negative copy of the input signal; providing the input signal to a first transmission gate, wherein the first transmission gate is capable of switching between on and off states; providing the negative signal to a second transmission gate, wherein the second transmission gate remains in the off state; and combining output signals from the first and second transmission gates, wherein the output signals of the first and second transmission gates cancel out when both the first and second transmission gates are in the off state to mitigate a leakage effect.