A 9-bit successive approximation ADC in SOI CMOS operating up to 300 degrees C

Abstract

Industrial electronics are in great demand for oil and gas exploration, well drilling, and automotive applications where the operating temperature goes beyond 200 degrees C. Circuit designs using conventional complementary metal-oxide semiconductor (CMOS) technology are mostly rated at maximum of 125 degrees C, which is not suitable for harsh environment. In this paper, a high-temperature (HT) 9-bit successive approximation register analog-to-digital converter (SAR ADC) designed in silicon-on-insolation CMOS technology with a sampling rate of 50kS/s is presented. The design considerations of the HT SAR ADC are discussed from process selection, temperature-aware circuit design, and measurement perspectives. The ADC achieves an effective number of bit (ENOB) of 8.35bits and a figure of merit of 93pJ/step at room temperature. Under HT test, ENOBs of 7.3bits at 225 degrees C and 6.9 bits at 300 degrees C are obtained. The power consumption is 1.52mW from a 5-V supply at room temperature and only 2.17mW at 300 degrees C. Copyright (c) 2015 John Wiley Sons, Ltd.