Patent ID: 6642751
Filing Date: 2003-11-04
Classification: G11C

Abstract:
A track-and-hold circuit comprising:(a) a pair of circuits each receiving first and second input signals and providing half of a differential output signal, wherein the first and second input signals received by each respective circuit are reversed relative to each other, and wherein each circuit comprises: (i) an amplifier; (ii) a configurable switch circuit coupled to a selected one of a plurality of selectable reference voltages based on a predetermined input signal type; (iii) a first switched capacitor circuit to sample its respective first input signal relative to an external common mode voltage in response to a first clock phase, and to couple the sampled first input signal in a feedback configuration between an output and a negative input of the amplifier in response to a second clock phase; and (iv) a second switched capacitor circuit to sample its respective second input signal relative to the external common mode voltage in response to the first clock phase, and to couple the sampled second input signal to a positive input of the amplifier relative to the selected one of the selectable reference voltages in response to the second clock phase; (b) wherein the amplifiers of the circuit pair collectively provide the differential output signal as a differential version of the difference between the sampled first and second input signals as shifted by the selected one of the selectable reference voltages.