A broadband 10-GHz track-and-hold in Si/SiGe HBT technology

High-performance multistage data converters and sub-sampling frequency down converters typically require track and hold amplifiers (THAs) with high sam pling rates and high linearity. This paper presents a THA for sub-sampling communications applications based on a diode bridge design with high-speed Schottky diodes and an improved current source approach for enhanced linear ity, Implemented in a 45-GHz BiCMOS Si/SiGe process, this IC has an input b andwidth in excess of 10 GHz, consumes approximately 550 mW, and can accomm odate input voltages up to 600 mV, With an input frequency of 8.05 GHz and a sampling frequency of 4 GHz,the THA has an IIP3 of 26 dBm and a spurious free dynamic range of 30 dB.