In this work, design technique and analysis of low energy consumption successive approximation register (SAR) analogue-to-digital converter (ADC) are presented. Despite the presence of parasitics, the dual capacitor array (CA) generates digital-to-analog (DAC) reference voltage with increased accuracy. The CA supports multiple parallel operations to enhance conversion speed. Unit sized capacitors in CAs are few in number and present good capacitance density, thereby providing area efficiency and ease of routing. A 9-bit SAR ADC using the proposed dual CA, implemented in a 90nm CMOS process, has a small core area footprint of 0.00371 mm^2 . At a 1 V supply and 100 KS/s, the ADC achieves an SNDR of 53.55 dB and consumes 0.47 µW, resulting in a figure of merit (FoM) of 14.5 fJ/conversion-step. #IETCircuitsDevices&Systems2018