A 12-bit cryogenic and radiation-tolerant digital-to-analog converter for aerospace extreme environment applications

This paper presents an 80-MHz 12-bit cryogenic low-power digital-to-analog converter (DAC) implemented in a 0.5-mu m SiGe BiCMOS technology. The cryogenic DAC is capable of operating over an ultrawide temperature (UWT) ranging from -180 degrees C to +120 degrees C and under the high-energy particle radiation environment on the lunar surface. A bandgap voltage reference for the UWT applications is designed using SiGe heterojunction bipolar transistors, and the current-steering DAC is implemented using a segmented current source array. The design considerations for both extreme temperature and radiation environments are discussed. The cryogenic and radiation-tolerant DAC chip occupies a die area of 3.5 x 1.8 mm(2) and consumes only 39.6 mW from a3.3-V supply voltage. The maximum DAC sampling rate was measured at 80 MS/s at -180 degrees C using a 40-pin dual in-line package.