A bipolar 2-GSample/s track-and-hold amplifier (THA) in 0.35 /spl mu/m SiGe technology

This paper describes the design and experimental implementation of a bipolar track-and-hold amplifier (THA) for use in an analog-to-digital converter suitable for wideband communication systems. A fully differential open-loop configuration was chosen in order to meet the required specifications. The THA was realized in a 0.35 /spl mu/m SiGe HBT process with an f/sub T/ of 65 GHz. The die size is 1.2 mm /spl times/ 1.2 mm, including pads. The THA features nine bit resolution up to input frequencies of 500 MHz at a sampling frequency of 2 GSample/s. From 500 MHz to 900 MHz, at the same sampling frequency, eight bit performance is observed. The power dissipation, including buffers, is 550 mW from a single 3.3 V power supply.