1) A 1.2V, 52mW, 210MS/s 10-bit two-step ADC in 130nm CMOS occupying 0.38mm . Using offset canceling comparators and capacitor networks implemented with small value interconnect capacitors to replace resistor ladder/multiplexer in conventional sub-ranging ADCs, it achieves 74dB SFDR for 10MHz and 71dB SFDR for 100MHz input. 2) A 32mW, 1.25GS/s 6-bit ADC with 2.5GHz internal clock in 130nm CMOS. A new type of architecture that combines flash and SAR enables the lowest power consumption, 6-bit >1GS/s ADC reported to date. This design can be a drop-in replacement for existing flash ADCs since it does require any post-processing or calibration step and has the same latency as flash. 3) A 0.4ps-rms-jitter (integrated from 3kHz to 300MHz offset for >2.5GHz) 1-3GHz tunable, phase-noise programmable clock-multiplier PLL for generating sampling clock to the SAR ADC. A new loop filter structure enables phase error preamplification to lower PLL in-band noise without increasing loop filter capacitor size.