Doris Schmitt-Landsiedel

Speeding up CMOS cameras and optical receivers by improved column multiplexer

A new method to compensate for the column multiplexer (MUS) in photo detector arrays is described and analyzed. It is based on a transimpedance amplifier with improved feedback structure. The focus is on arrays where the photo current is directly used as signal. If this current is transferred to the global transimpedance amplifier by a multiplexer, the resistance of te MUX transistor causes a significant speed degradation. Measurements of a test chip in 0.19micrometers CMOS are presented. It turns out that using the proposed circuit it is possible to almost fully compensate for the MUX in terms of speed and signal amplitude with only little layout area penalty.

From Roadmaps to Reality: The Challenges of Designing Tomorrow's Chips

Ever smaller structures and ever greater numbers of semiconductor elements on a single chip call for a growing level of interdisciplinary creativity among chip and system developers. Also required are measures designed to significantly reduce the power dissipation associated with each function, even as clock rates accelerate. As integration increases, another requirement is to integrate combinations of analog and digital circuits on a single chip.