Time-Domain Versus Voltage-Domain Data Conversion: Principles, opportunities, and challenges

Exponentially growing demand for data bandwidth has created a persistent need for high-speed, low-cost, and power-efficient data converters. In many applications, tight integration of converters with digital processing is essential to minimize interface costs. While analog circuits have historically relied on voltage-domain encoding and signaling, time-domain circuits, where signals are encoded in the phase of digital signal transitions, are gaining popularity for their ability to achieve high-speed area-efficient operation in digital-optimized process nodes. This article explores the principles of time-domain ADCs in comparison to their voltage-domain counterparts, using the SAR algorithm as a central example. It highlights the advantages and limitations of each approach and concludes with an overview of hybrid architectures that combine the strengths of both domains.