Analog-to-Digital Converter (ADC) design plays an important role for accurate and efficient interfacing of real-world signals for IoT platforms embedded with multiple sensors. In this paper, a Flash or direct conversion 4-bit and 5-bit ADCs are designed and implemented in 90nm CMOS. The performance of the flash ADC is evaluated against important performance metrices. The proposed 4-bit ADC achieve a power consumption of 1.41mW, SNR of 26.184dB, 3.71 ENOB and 16.19 pJ/step of FoM and 5-bit ADC achieve a power consumption of 2.921mW, SNR of 31.149dB, 4.51 ENOB and 19.12 pJ/step of FoM.