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<span>Differential successive approximation register (SAR) of analog to digital converter (ADC) requires two balancing input signals that have same amplitude with 180⁰ out of phase. Otherwise, it performs inaccurately and degrades the performance during ADC testing procedure. Therefore, an implementation of AD8139 chip single to differential amplifier was chosen as an ADC driver to generate sufficient differential output for the ADC. The chip was placed on a printed circuit board (PCB) to test the functionality as well as the performance of static and dynamic SAR ADC. The result shows that the single-ended input transform into differential voltage outputs. The amplitudes for the amplifier remain equal and is 180° out of phase for DC and AC voltage input signal. Besides, the fabricated 0.18µm CMOS technology of differential 10-bit SAR ADC is capable of digitising full code digital output and perform 9.5-bit effective number of bit (ENOB) from analog input driving by the ADC driver.</span>

Power consumption and speed are the main criteria in designing comparator for analog-to-digital converter (ADC). This paper presents an optimized low voltage low power dynamic comparator which is robust to process, voltage and temperature (PVT) variations with adequate speed. The comparator circuit was designed using 0.18µm CMOS technology with low voltage supply of 0.8V. The method used to verify the robustness of the comparator circuit across 45 PVT is presented. The circuit is simulated with 10% voltage supply variation, five process corners and temperature variation from 0°C to 100°C. The simulation result show that the proposed comparator circuit achieved significant reduction of power consumption and delay during worst case condition compared to dynamic comparator proposed from previous researchers.

Imbalance and out-of-range input signals can cause inaccuracy in fully differential successive approximation (SAR) analog to digital converter (ADC). Therefore, implementation of an ADC driver can solve the problem since the input can be properly adjusted to suit with an ADC input. AD8139 single to differential amplifier was chosen as an ADC driver in this design and placed on a printed circuit board (PCB) to drive differential input signal of SAR ADC. The result shows each of output amplitude of the amplifier remains equal and is 180° out of phase for DC and AC input signal. The fabricated 10 bit SAR ADC is capable to digitize full code from analog input produced by the ADC driver.

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