Design of High-esolution Comparator Applied in 14 bit SAR ADC

Based on preamplifier-latch theory, a high-resolution comparator with three pre-amplifiers and a latch is presented.In order to achieve high-resolution, both IOS and OOS offset cancellation technique is used, which successfully decreases the input offset voltage.The traditional dynamic offset test method is time consuming, so a new dynamic offset test bench containing a negative feedback loop is adopted, which efficiently speeds up the design and simulation.The simulation results show that comparator can distinguish 33.2 μV under hhnec CZ6H (0.35 μm) process.It is suitable for the 14 bit SAR ADC.