A 5-bit, 18 GS/sec SiGe HBT track-and-hold amplifier

An ultra-high-speed track-and-hold amplifier (THA) using a switched-emitter-follower (SEF) configuration is presented. Implemented in a commercially-available 0.18 /spl mu/m 120 GHz SiGe HBT BiCMOS technology, the THA core occupies a compact area of only 120 /spl times/ 200 /spl mu/m/sup 2/. The THA can operate at a sampling rate of 18 GS/sec with a total harmonic distortion (THD) of -32.3 dBc, and dissipates 128 mW, significantly smaller than other THAs in the literature operating at similar sampling rates.