The invention provides a successive approximation type analog-to-
digital converter and a calibration method. The successive approximation type analog-to-
digital converter comprises a sampling / holdingcircuit, a digital-to-analog converter, a 
comparator, a successive approximation logic circuit, a 
clock generation circuit and a digital pseudo-random 
signal generator. An analog input 
signal is connected to the sampling / holding circuit. Positive and negative input ends of the 
comparator are connected with the digital-analog converter and the sampling / holding circuit respectively, and the output end of the 
comparator is connected with the successive approximation logic circuit; the successive approximation logic circuit and the digital pseudo-random 
signal generator are connected to the inputof the 
adder, and the output of the 
adder is connected with the digital-to-analog converter; the successive approximation logic circuit and the digital pseudo-random 
signal generator are connected tothe input of a subtracter, and the output of the subtracter is a final output result; and the 
clock generation circuit is respectively connected with the comparator and the successive approximation logic circuit. 
Harmonic energy is reduced, the spurious-free 
dynamic range of the ADC is improved, and the 
linearity of the core ADC is effectively improved.