Low-jitter differential clock driver circuits for high-performance high-resolution ADCs

Abstract

High-performance analog to digital converters (ADCs) require low-jitter clocks in order to obtain high resolutions (above 12 effective bits) at high-speed operation frequencies (input frequency higher than 80MHz). In these ultra-low-jitter applications, clock driver circuits consider multi-stage architectures usually comprised by a front-end differential amplifier, and a differential-to-single (D2S) conversion in voltage mode, followed by an output digital buffer. This paper proposes an alternative to perform the D2S operation in current mode as a way to optimize the trade-offs between power consumption and output jitter. Different clock driver circuit topologies with ultra-low-jitter specifications (<; 200fs) are introduced and compared in a 0.18μm commercial CMOS process.