A low propagation delay dispersion comparator for a level-crossing AD converter
ABSTRACT This paper presents the design of a continuous time voltage comparator with low propagation delay dispersion. The comparator
is intended to be used as a building block for a level-crossing AD converter: a type of AD converter where the sampling moments
are triggered when an input signal crosses predetermined threshold levels. This type of system sets very high demands on the
time measurement and the comparator to achieve the desired performance. The comparator design is based on several techniques
to minimize the comparator propagation delay dispersion. The comparator has been implemented in a 0.35μm BiCMOS process.
Measured results show good agreement with simulations. The slew rate related propagation delay dispersion is measured to 90ps
for an input frequency range from 3to 10MHz and amplitudes from 200mV to 1.65V. The comparator static power consumption