A Compact Inverter‐Based Temperature Compensation for a Subthreshold Analogue Front‐End in Noise‐Shaping SAR ADC

ABSTRACT This letter presents an adaptive temperature compensation technique for a subthreshold analogue front‐end (AFE) in low‐power application. The conventional subthreshold AFE suffers from significant temperature dependency, compromising performance over a wide operating range. To overcome this critical issue, the proposed technique provides adaptive performance compensation, driven by a compact inverter‐based sensor that identifies the current operating zone. This work was fabricated in a CMOS process, where the core compensation blocks occupy a compact area of only . To demonstrate its advantages, the proposed circuit was integrated with an AFE‐embedded noise‐shaping SAR ADC. Measurement results confirm robust performance for the entire system across a −40 to range, with the proposed technique improving the average SNDR by at low temperatures and achieving a power reduction of at high temperatures. Notably, the compensation unit consumes less than of the total system power.