8-bit 250 MSPS Two-Step Flash ADC ASIC Design

Low power consumption and a high data rate are requirements for modern wireless communication devices. Analog-to-digital converters are the essential parts of the portable device that serve as an interface between the analog and digital domains. Low-power approaches for high-speed applications are becoming more and more important as the market for portable devices grows. Small feature-size processes can help cut down on power consumption. However, process variances and other factors impact the device’s performance as power consumption decreases. The three main needs for portable devices are low power consumption, medium resolution, and high speed. The design of an 8-bit 250 MSPS ADC is the project’s objective. This ADC ASIC is a mixed signal. This ADC ASIC is mixed signal. This design uses a subranging type 2-step flash ADC architecture. The 4-bit flash type ADC is designed in two stages. Sample and hold block, comparator block, op-amp, bias circuit, and TGB encoder make up the ADC design. A versatile operational amplifier (op-amp) is developed that can be employed in three distinct ADC modules: S/H amplifier, Subtractor, and Residual amplifier. Upon thorough examination of various op-amp topologies in relation to the provided specifications, the Two Stage Folded Cascade topology was chosen. The Cadence Virtuoso 6.1.5 spiced simulator was utilized for the design, implementation, and analysis of the ADC in 180nm technology.