A generic low-noise CMOS readout interface for 64 × 64 imaging array with on-chip ADC

Abstract

This paper presents a low-noise and high dynamic-range CMOS readout-IC (ROIC) for a 64 × 64 array of opto-electrical sensors. The readout chain comprises a pixel preamplifier array, correlated-double-sampling based switched-capacitor gain blocks, class-AB output buffer for driving off-chip loads and a 12-bit pipeline ADC for on-chip digitization. The pixel preamplifiers array, occupying an area of 30 μm × 30 μm per pixel, can either be hybridized to a separate IR or UV sensor or can be used as monolithic visible-light active CMOS pixel-array after exposing (by etching the pad) the embedded photodiode under the bonding pads. The ROIC is designed and fabricated in 0.25 μm 1P/5 M CMOS technology with 5 mm × 5 mm of total dimensions. The integrated readout chain, in integrate-then-read mode, demonstrates a dynamic range of 72 dB for electrically emulated sensor currents from 25 pA to 100 nA. It can support a frame rate of 700 fps, with single fully-differential analog as well as 12-bit digital output, at 10 MHz while consuming 17 mW with on-chip biases.