In order to keep the analog to digital converter's speed and precision

a sample-and-hold(S/H) circuit for a 12-bit 40-MS/s pipeline ADC is designed and fabricated using a 0.18 micrometer process.The proposed amplifier can simplify the design and occupies smaller area.The substrate bias effect of the switch transistor used in the bootstrapped switch can be eliminated with the silicon-on-insulator (SOI) process

which can increase the linearity of bootstrapped switch and improve the performance of the S/H circuit.The S/H circuit occupies an area of 0.023 square millimeter.Measurement results show that the S/H circuit operates at a 1.5 V supply and consumes 3.5mW

and the spurious free dynamic range is 76.85 dB for a 1 MHz input signal with 40 MS/s sampling rate.The S/H circuit meets the requirement of the 12-bit 40-MS/s pipeline analog to digital converter.