A 1-V 1.25-GS/S 8-bit self-calibrated flash ADC in 90-nm digital CMOS

We present an 8-bit 1.25-GS/s flash analog-to-digital converter (ADC) in 90-nm digital CMOS with wide analog input bandwidth and low power dissipation. The ADC employs two key techniques: a self-biased track-and-hold amplifier which enhances the ADC full-scale voltage and enables the converter operating under a single 1-V supply; and an improved calibration scheme based on reference pre-distortion to enhance the ADC linearity without sacrificing its sampling speed. The prototype converter thus achieves 7-, 6.9-, 6.5-bit ENOB at 1.25 GS/s for input signal frequencies of 10 MHz, 600 MHz, and 1.3 GHz, respectively, and better than 52-dB SFDR across the full Nyquist-band, while dissipating 207 mW from a single 1-V supply.