<title>A High Resolution CCD Multiplexer</title>

Abstract

This paper describes a high resolution CCD multiplexer for focal plane imaging systems. The multiplexer incorporates quadrilinear readout registers to achieve two times the resolution of conventional bilinear structure while using the same design rules. Complete parallel charge transfer are ensured by a novel buried channel poly gate isolation scheme. A monolithic silicon photodiode array of 8µm pitch, 3533 elements was designed with the multiplexer.Video preprocessing circuits of high speed four to one channel stitching, compensated sample and hold and bad pixel deletion were integrated on chip for improved performance. The modulation transfer functions due to the geometry and the transfer inefficiency are discussed. The theoretically calculated total MTF agrees with the experimental result. At Nyquist frequency of 62.5 c/mm the total MTF is better than 0.6 in the absence of the diffusion MTF degradation. The noise spectrum of the CCD and the output amplifier are presented. The RMS noise of the CCD in dark is approximately 0.35 my over 1 MHz bandwidth. The CCD noise increases with light input attributed primarily to the shot noise. The low noise nature of the multiplexer makes it ideal for the high resolution low light level detection applications.