Noise Coupling Effects on CMOS Analog-to-Digital Converter in Magnetic Field Wireless Power Transfer System Using Chip-PCB Comodeling and Simulation

Abstract

Analog-to-digital converter (ADC) is becoming of utmost importance in an automotive environment. With the increased number of magnetic field sources near the ADC that can alter its behaviors significantly, we need to model how magnetic field affects the performance of the ADC. Therefore, in order to accurately evaluate the practical performance of the ADC and the considerable off-chip and on-chip effects that are highly complex, the chip-printed circuit board (PCB) comodeling, cosimulation, and coanalysis are required. In this study, a comodel of the magnetic field effects on an ADC is proposed. The proposed comodel includes three separate submodels: a model of the magnetic field coupling from the wireless power transfer (WPT) system input to the PCB integrated with ADC, a model of the noise coupling from the PCB to the ADC input, and a model of the ADC behavior from the ADC input to the ADC outputs. Considering the magnetic field coupling from the magnetic field source to the PCB, a new inductive transmission line model (I-TLM) method is developed. This method achieves fast, precise, and broadband estimation of the magnetic field effects in comparison to previous estimation methods. To validate the proposed comodel, an ADC is fabricated using a 0.13-μm complementary metal-oxide semiconductor process and is wire-bonded to the designed PCB for ADC. A PCB-level WPT system is designed and built as the magnetic field source. The performance factor of the ADC is measured by sweeping the WPT system input frequency from 100 kHz to 1 GHz to find out the critical WPT system frequency for the designed ADC with the chip-PCB hierarchical structure. The results estimated by the proposed model correlate well with the full 3-D electromagnetic field simulation and measurement. The proposed modeling procedure reduces the time and computation resource in the design of the chip, package, and PCB to achieve high-quality analog devices or mixed-mode systems, while also providing an intuitive understanding of the radiated noise effect.