A 8-bit 500-KS/s low power SAR ADC for bio-medical applications

This paper presents a successive approximation register analog-to-digital converter (SAR ADC) design for bio-medical applications. An energy-saving switching sequence technique is proposed to achieve low power consumption. The average switching energy of the capacitor array can be reduced by 56% compared to a conventional switching method. The measured signal-to-noise-anddistortion ratios of the ADC is 46.92 dB at 500KS/s sampling rate with an ultra-low power consumption of only 7.75-μW from a 1-V supply voltage. The ADC is fabricated in a 0.18- μm CMOS technology.