Research :: ECE :: UD


Computer Systems

Design of 2D Read-out Integrated Circuit for 3-D Laser-radar Imaging Systems

Fouad Kiamilev

Design of read-out circuits for infrared systems is increasingly challenging due to larger format photodetector arrays with smaller pixels, coupled with requirements for higher sensitivity and lower power dissipation. Traditional read-out techniques involve photocurrent-to-voltage conversion at the cell level by means of an integrating capacitor. Our previous work in this domain demonstrated an alternative read-out scheme that uses orthogonal carriers to modulate the photo-currents so that the signals from an entire row can be read simultaneously without loss of optical power. In order to improve the system sensitivity and to minimize the effects of electronic offset and power supply noise, a fully differential architecture has been implemented. Thus, at the end of each row, the differential busses are fed to fully differential capacitive transimpedance amplifiers (CTIA's) that take care of the current-to-voltage conversion. Their outputs are driven externally for digitization and post processing. Different generations of the read-out integrated circuit have been designed, fabricated, and tested featuring increasingly smaller feature technologies such as 0.35 μm, 0.18 μm, and 90 nm. The 2-D read-out integrated circuit is designed to function as a front-end module for an amplitude modulated/continuous time AM/CW 3-D Ladar imager under development at the Army Research Laboratory.

Recent publications

J. Helou, J. Garcia, M. Sarmiento, F. Kiamilev, and W. Lawler, "0.18 μm CMOS fully differential CTIA for a 32x16 ROIC for 3D ladar imaging systems," Proceedings of SPIE, vol. 6294, Infrared and Photoelectronic Imagers and Detector Devices II, Randolph E. Longshore, Ashok Sood, Editors, 629409 (Sep. 7, 2006)

J. Garcia, W. Lawler, N. Waite, and F. Kiamilev, "0.5 μm CMOS orthogonal encoding readout cell of active imaging systems," IEEE Journal of Selected Topics in Quantum Electronics, vol. 10, pp. 803-810, 2004.

J. Garcia, F. Kiamilev,, "Electronically Code-Multiplexed Readout of Photo-Detector Arrays," US Patent Application No. 11/104,918 (Filed on April 14, 2005).

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