While data converters have been around for nearly nighty years, mm-wave data converters are still in their infancy. Only recently the 40-GHz sampling barrier was broken with the introduction of the next generation high-speed sampling oscilloscopes. Meanwhile, data communication is the main driving force behind mm-wave data converter development. As with any mm-wave circuit, designers must go beyond simply relying on technology advancement to archives acceptable performance. Careful device and passive modeling is critical and systematic design methodology may offer repeatable and scalable mm-wave designs. In this book the design methodology and architectural challenges of mm-wave ADCs are explored. Some of the fundamental mm-wave ADC building blocks such as track and hold amplifiers, data distribution networks and flip-flops are implemented in SiGe BiCMOS and CMOS technologies and characterized. Several record breaking circuits are presented along with systematic design methodology. The impact of these circuit blocks on the performance of the next generation ADCs is studied and experimentally verified using a 35-GS/s, 4-bit ADC-DAC chain implemented in a SiGe BiCMOS technology.