A 80x60 Micro-Bolometer CMOS Thermal Imager Integrated with a Low-Noise 12-Bit DAC

Abstract

A low-cost 80x60 micro-bolometer CMOS thermal imager is presented. The imager system integrated with a proposed 12-bit biasing digital-to-analog converter (DAC) has 100 ms start-up time, which is 300x faster than commercial products, while ensuring comparable 100 mK noise-equivalent temperature difference (NETD). The low-noise biasing DAC adopts a current-mode divider- stacking structure and a bit-inversion technique, leading to mismatch-insensitive operation. The 12-bit biasing DAC in a 0.18 m CMOS imager IC has a low noise of 1.89 Vrms and INL/DNL of 0.14/0.09 LSB, respectively.