A 0.0016 mm² 0.64 nJ leakage-based CMOS temperature sensor

Area of Science:

• Electrical Engineering
• Materials Science
• Semiconductor Physics

Background:

• Accurate temperature sensing is critical for integrated circuit (IC) performance and reliability.
• Traditional temperature sensors face challenges with process variations and energy consumption in advanced nodes.
• Leakage currents in Metal-Oxide-Semiconductor (CMOS) technology offer a basis for temperature-dependent sensing.

Purpose of the Study:

• To develop a highly accurate and robust CMOS temperature sensor for the 65 nm node.
• To mitigate the impact of process fluctuations on sensor performance.
• To propose a novel charging mechanism for enhanced fabrication variability tolerance.

Main Methods:

• Utilizing the thermal dependencies of leakage currents in CMOS transistors operating in the subthreshold regime.
• Implementing a ratio of two capacitor discharge time measurements to compensate for process variations.
• Introducing a novel capacitor charging mechanism for improved robustness.

Main Results:

• Achieved a sensor resolution of 0.28 °C.
• Demonstrated a 3σ inaccuracy of 1.17 °C over the 40-110 °C temperature range.
• The sensor occupies a small area (0.0016 mm²) with low energy consumption (47.7-633 pJ/sample).

Conclusions:

• The proposed CMOS temperature sensor offers a robust and accurate solution for integrated circuit applications.
• The novel design effectively compensates for process variations, enhancing reliability.
• The sensor's small footprint and low power consumption make it ideal for miniaturized electronic systems.