A novel low power 11-bit hybrid ADC using flash and delay line architectures

This paper presents a novel low power 11-bit hybrid ADC using flash and delay line architectures, where a 4-bit flash ADC is followed by a 7-bit delay-line ADC. This hybrid ADC inherits accuracy and power efficiency from flash ADCs and delay-line ADCs, respectively. Also, in order to reduce the power of the first stage flash ADC, a power-saving technique is adopted by biasing the DC tail current of the preamplifiers at 5μA instead of the operational current, 47μA in stand-by mode. The hybrid ADC was designed and simulated in a commercial 65nm process. With 1.1 V supply and 100 MS/s, the ADC achieves an SNDR of 60 dB and consumes 1.6 mW, which results in a figure of merit (FOM) of 19.4 fJ/conversion-step without any calibration technique. Also, Monte Carlo simulations are performed with a 3σ device mismatch for the SNDR estimation, and the SNDR is observed to be better than 58.5 dB.