TIMING-MISMATCH ANALYSIS IN HIGH-SPEED ANALOG FRONT-END WITH NONUNIFORMLY HOLDING OUTPUT

This paper will present a practical and complete analysis of timing-mismatch effects for high-speed Analog Front-End (AFE) systems with the inherent nonuniformly holding outputs. The analysis reveals first the relationship with traditional impulsesampled timing-mismatch effects and then its closed-form expressions of the signal-to-noise-ratio (SNR), in terms of the number of channels, signal frequency, and jitter errors. Both timing errors imposed by random clock-jitter and fixed periodic clockskew will be analyzed. Practical analysis examples for a very highspeed data-converter as well as a AFE filtering will be addressed to illustrate the effectiveness of the derived formula. 1

Review and Selection Strategy for High-Accuracy Modeling of PWM Converters in DCM

Among various modeling methods for DC-DC converters introduced in the past two decades, the state-space averaging (SSA) and the circuit averaging (CA) are the most general and popular exhibiting high accuracy. However, their deduction approaches are not entirely equivalent since they incorporate different averaging processes, thus yielding different small signal transfer functions even under identical operating conditions. Some research studies claimed that the improved SSA can obtain the highest accuracy among all the modeling methods, but this paper discovers and clearly verifies that this is not the case. In this paper, we first review and study these two modeling methods for various DC-DC converters operating in the discontinuous conduction mode (DCM). We also streamline the general model-deriving processes for DC-DC converters, and test and compare the accuracy of these two methods under various conditions. Finally, we provide a selection strategy for a high-accuracy modeling method for different DC-DC converters operating in DCM and verified by simulations, which revealed necessary and beneficial for designing a more accurate DCM closed-loop controller for DC-DC converters, thus achieving better stability and transient response