A fast convergent and energy efficient offset calibration technique for dynamic comparators

A novel offset calibration technique with fast convergence rate for high-speed dynamic comparators is presented. The circuit utilizes a multi-rate charge pump circuitry to speed up the calibration process while maintaining the precision which leads to better energy efficiency. The circuit is designed in a 0.13μm CMOS process. Based on Monte-Carlo simulation results the comparator achieves 183.1μV residual offset within an average convergence time of 82 ns. Based on measurement results the comparator dissipates 5.1 μW from a 1 V power supply at 250 MHz clock frequency, achieving a FOM of 10.2 fJ/conv.