A comparison of totally digital ADCs for SOCs

Presently, most system on chip (SoC) applications are mainly composed of digital devices. However, since SoCs also need to acquire data from the physical world, there is an increasing demand for ADCs designed on digital substracts. The core concept is to substitute the complexity of analog circuitry and not so advanced technology for easily available digital computation. This work compares two of the recently proposed totally digital analog conversion design strategies. The first approach is an ADC based on a voltage-to-delay conversion, and the second one is based on statistical sampling with a low-cost one bit comparator. The main characteristics of the designs are analyzed, and both systems were implemented, with measured data validating the theoretical results.