A CMOS binary position-sensitive photodetector (PSD) array

Implementation and test results of a 16 by 16 binary CMOS photodetector array for position sensing applications is presented. Unlike conventional position sensitive detectors (PSDs), it is capable of simultaneous multiple spot detection with high accuracy. To decrease signal processing overhead characteristic of this kind of area arrays, binary detection with on-site thresholding and random access readout is used. The fill factor and pitch of the array are 30% and 50 /spl mu/m, respectively. Quantization limited position sensing accuracy of 4.3 /spl mu/m is achieved using spot of a 280 /spl mu/m in diameter, total signal power of about 8 nW and pulse width of 8 ms. The sensitivity is limited by the spatial noise caused by the mismatch of threshold setting current mirrors operating in weak inversion.