[Paper] 3D Stacked Imager featuring Inductive Coupling Channels for High Speed/Low-Noise Image Transfer

Abstract

This paper proposes 3D stacked module consisting of image sensor and digital logic dies connected through inductive coupling channels. Evaluation of a prototype module revealed radiation noise from the inductive coils to the image sensor is less than 0.4-LSB range along with ADC code, i.e., negligible. Aiming at high frame rate image sensor/processing module exploiting this attractive off-die interface, we also worked on resolving another throughput-limiter, namely power consuming Time to Digital Converter (TDC) used in column parallel ADCs. Novel intermittent TDC operation scheme presented in this paper can reduce its power dissipation 57% from conventional ones.