Very high-speed BJT buffer for track-and-hold amplifiers with enhanced linearity

This paper presents new design techniques to enhance low and high frequency track mode linearity of the switched emitter follower structure used in very high-speed track-and-hold amplifiers. Simulations using a 0.8 /spl mu/m 5 V SiGe BICMOS process and symbolic harmonic distortion analysis verify the performance of the proposed techniques. Analysis results show a third harmonic better than -105 dB with 1.5 V/sub pp/, at 100 MHz for a 1.6 pF hold capacitor.