5.9 An 18.75µW dynamic-distributing-bias temperature sensor with 0.87°C(3σ) untrimmed inaccuracy and 0.00946mm2 area

The temperature sensing of a chip becomes more critical with the increment of the process and circuit complexity. In advanced processes, the heating effect becomes more severe due to the thermal accumulation within the small chip dimension. In order to provide precise and on-chip local thermal sensing, some structures have been demonstrated [1–7]. The paper presents an ultra-low-power, compact and accurate temperature sensor without trimming for the local heat monitors of SOCs. The approach of the dynamic-distributing-bias temperature sensor efficiently reduces the power consumption and chip area simultaneously with accurate digital outputs. The overall area of the circuit is 0.00946mm2, which shows larger than 2× area reduction compared with the prior art [1–3]. The prototype performs state-of-the-art power consumption of 18.75µW and untrimmed relative 3σ inaccuracy [8] achieving 1.64% among the previous compact temperature sensors with process scales smaller than 40nm [3–7].