Thermal Noise in Track-and-Hold Circuits: Analysis and Simulation Techniques

As a vehicle that lets us explore the main ideas of this article, we will utilize the commonly used charge-redistribution track-and-hold amplifier (THA) circuit (shown in Figure 1) and evaluate this circuit in terms of its thermal noise performance. Of course, it is well know that the thermal noise of this circuit is somehow related to “kT/C.” What we accomplish in this article is to precisely track down the proper proportionally constants so that we can validate the results of a circuit simulation with good precision. After all, as you have learned from your experienced analog guru, you will never trust a circuit simulation blindly, right?