In this book, various metal-insulator-metal (MIM) capacitor-based differential Voltage-to-Time Converters (VTCs) including 2 novel proposed designs, which achieve a high performance at higher sampling frequency for a Software-Defined Radio (SDR) receiver at 65-nm CMOS technology, are presented and compared to their single-ended design. A study on tolerating the process-voltage-temperature (PVT) variations for the first proposed design with proposing a dynamic calibration technique based on a set of large-sized capacitor-based voltage dividers circuits is presented. Post-layout simulation results are provided for both designs at 130-nm CMOS technology for low-frequency low-power implantable biomedical systems.