A 0.5 V 1.1 MS/sec 6.3 fJ/Conversion-Step SAR-ADC With Tri-Level Comparator in 40 nm CMOS

作者：Shikata Akira^*; Sekimoto Ryota; Kuroda Tadahiro; Ishikuro Hiroki

来源：IEEE Journal of Solid-State Circuits, 2012, 47(4): 1022-1030.

DOI：10.1109/JSSC.2012.2185352

• ADC
• CMOS
• low-voltage
• meta-stable
• reconfigurable DAC
• successive approximation
• tri-level comparator

This paper presents an extremely low-voltage operation and power efficient successive-approximation-register (SAR) analog-to-digital converter (ADC). Tri-level comparator is proposed to relax the speed requirement of the comparator and decrease the resolution of internal Digital-to-Analog Converter (DAC) by 1-bit. The internal charge redistribution DAC employs unit capacitance of 0.5 fF and ADC operates at nearly thermal noise limitation. To deal with the problem of capacitor mismatch, reconfigurable capacitor array and calibration procedure were developed. The prototype ADC fabricated using 40 nm CMOS process achieves 46.8 dB SNDR and 58.2 dB SFDR with 1.1 MS/sec at 0.5 V power supply. The FoM is 6.3-fJ/conversion step and the chip die area is only 160 mu m x 70 mu m.

• 出版日期2012-4