A 500-MS/s 3-Bit Flash ADC with 238.5 fJ/conv.-step in 65-nm CMOS Technology

This paper presents the design and implementation of a high-speed 3-bit flash analog-to-digital converter (ADC) for the rapid conversion of analog signals into digital representations. The designed ADC, implemented in a 65 nm CMOS process, utilizes seven comparators and a resistor ladder network for reference voltage generation. Operating at a supply voltage of 1.2 V, the ADC achieves a conversion time of just a few nanoseconds, making it highly suitable for high-speed signal processing applications. With a sampling rate of $500 \mathrm{MS} / \mathrm{s}$, the ADC consumes $842.2 \mu \mathrm{~W}$ and demonstrates a signal-to-noise and distortion ratio (SNDR) of 18.72 dB, corresponding to an effective number of bits (ENOB) of 2.82. The figure of merit (FoM) of the design is calculated at 238.53 fJ/conversion, indicating an optimal balance between speed and power efficiency. These performance metrics highlight the ADC’s suitability for high-frequency applications that require fast response times and low power consumption.