The Design of High Linear Bootstrapped S/H Switch

Sometimes, the input-port of A/D converter always needs a S/H switch. In Sample state, the S/H switch should always be opening, now voltages between input-port and output-port in S/H switch are always the same. In Hold state, the S/H switch should always be closing, now the voltage of output-port in S/H switch will keep a fixed value, and it will not be changed with the voltage of input-port in S/H switch. For A/D converter, the conversion linearity is the most important parameter. For getting the best performance of conversion linearity, it is very important to design a high linear S/H switch. In sample stage, the voltage of output-port in S/H switch should be always changed with the voltage of input-port at any time. It is very easy to S/H switch design under the normal condition. Next for getting the higher linear performance in A/D converter, the fixed value in Hold state should be keeping linear performance of input voltage at the most, it is very hard in high resolution A/D converter. Through this paper's design, it makes the distortion leading by Sample switch become linear distortion. So it can get a high performance S/H bootstrapped switch, which can apply to 16-bit or much higher resolution ADC.