Some applications require electronic systems to operate at extremely high temperature. Extending the operating temperature range of automotive-grade CMOS processes -- through the use of dedicated design techniques -- can provide an important cost-effective advantage. We present a second-order discrete-time delta-sigma analog-to-digital converter operating at a temperature of up to 250 $^\circ$C, well beyond the 175 $^\circ$C qualification temperature of the automotive-grade CMOS process used for its fabrication (XFAB XT018). The analog-to-digital converter incorporates design techniques that are effective in mitigating the adverse effects of the high temperature, such as increased leakage currents and electromigration. We use configurations of dummy transistors for leakage compensation, clock-boosting methods to limit pass-gate cross-talk, and we optimized the circuit architecture to ensure stability and accuracy at high temperature. Comprehensive measurements demonstrate that the analog-to-digital converter achieves a signal-to-noise ratio exceeding 93 dB at 250 $^\circ$C, with an effective number of bits of 12, and a power consumption of only 44~mW. The die area of the converter is only 0.065~mm$^2$ and the area overhead of the high-temperature mitigation circuits is only 13.7%. The Schreier Figure of Merit is 140~dB at the maximum temperature of 250 $^\circ$C, proving the potential of the circuit for reliable operation in challenging applications such as gas and oil extraction and aeronautics.

翻译：某些应用要求电子系统在极高温度下工作。通过采用专门的设计技术，扩展车规级CMOS工艺的工作温度范围，可以提供重要的成本效益优势。本文提出了一种工作温度高达250°C的二阶离散时间Delta-Sigma模数转换器，该温度远超其制造所用车规级CMOS工艺（XFAB XT018）的175°C认证温度。该模数转换器采用了能有效缓解高温不利影响（如泄漏电流增加和电迁移）的设计技术。我们使用虚拟晶体管配置进行泄漏补偿，采用时钟提升方法来限制传输门串扰，并优化了电路架构以确保高温下的稳定性和精度。全面的测量结果表明，该模数转换器在250°C下实现了超过93 dB的信噪比，有效位数达到12位，功耗仅为44 mW。转换器的芯片面积仅为0.065 mm²，高温缓解电路的面积开销仅为13.7%。在最高温度250°C下，其Schreier品质因数达到140 dB，证明了该电路在石油天然气开采和航空等具有挑战性的应用中实现可靠运行的潜力。