Switching Schemes for Reducing Capacitor Mismatch Sensitivity of Quasi-Passive Cyclic DAC

An alternately complementary switching is proposed to reduce the quasi-passive cyclic DAC error caused by capacitor mismatch, and a hybrid switching is adopted to further enhance its accuracy. With 1.1% moderate capacitor mismatch, the achievable effective number of bits is as high as 15. It is shown that a three-fold improvement in accuracy can be fulfilled by the proposed hybrid switching. Since the DAC owns better immunity to process variations, smaller capacitors can be utilized to diminish both chip cost and power consumption.