应用于10bit 10MSPS SAR ADC的自举采样开关的设计

Design of a Bootstrapped Sampling Switch Applied for 10 Bit 10MSPS SAR ADC

摘要: 基于Global Foundries 0.18μm CMOS工艺,设计了一种用于10bit 10MSPS SAR ADC的栅压自举采样开关电路.讨论了互补型CMOS采样开关和传统的栅压自举采样开关的不足,提出了一种新型的栅压自举采样开关电路结构,有效地提高了该电路的可靠性.仿真结果表明:当输入信号频率接近奈奎斯特频率时,该栅压自举采样开关电路的信噪比可以达到72dB,可以适用于10bit 10MSPS SAR ADC的应用需求.

Abstract: A bootstrapped sampling switch applied for 10 bits 10MSPS SAR ADC is designed based on the Global Foundries 0.18μm CMOS process.The disadvantages of complemented CMOS sampling switch and conventional bootstrapped sampling switch are discussed.A new bootstrapped sampling circuit topology is presented to efficiently achieve high reliability.Simulation result shows that the SNDR of the proposed circuit can reach 72 dB when input signal frequency closes to Nyquist frequency,which satisfies the requirement of 10 bits 10MSPS SAR ADC.