64×64-element photocurrent multiplexer for infrared staring array application

The design and operation of a 64×64 two-dimensional photocurrent multiplexer are described. The array is arranged on a 60-μm pitch. Direct-injection input is used from an IR photodiode array bump-bonded directly onto the top of the chip. Multiplexing is achieved using a MOSFET/CCD architecture with no column-transfer CCDs. The serial output is synchronized by means of line-sync and frame-sync pulses. Sixty-four rows of 64 pixels are transferred to a CCD and clocked out serially. Output is in the form of a continuous analog signal and a double-correlated clamp sample-and-hold output stage has been used to reduce 1/f and partition noise. A means has been incorporated for electrically introducing charge to the storage sites for test purposes. The devices have been successfully bonded to the diode arrays with a high yield and test results agree closely with performance predictions.