Temperature‐Insensitive On‐Chip Resistors for Linear Voltage‐To‐Current Conversion in Low‐Power Voltage and Current References

ABSTRACT

On‐chip resistors are susceptible to temperature variations, affecting the performance of linear voltage‐to‐current (VI) conversion and vice versa. This paper introduces an approach to implement resistive networks that are highly immune to temperature variations across a wide range by combining complementary‐to‐absolute‐temperature (CTAT) and proportional‐to‐absolute‐temperature (PTAT) resistors existing in standard CMOS technology. The proposed resistive networks, aiming for linear VI conversion in voltage and current references (VCRs), yield ultra‐low temperature coefficient (TC). Optimization is carried out using a multi‐objective heuristic algorithm to find the optimal placement, TC and sizes of the elements within the final configuration. Post‐layout simulation results in a standard 0.18‐μm CMOS process demonstrate the possibility of implementing sub‐3 ppm/°C resistors across −40 ~ 120°C temperature range, improving the prior art by more than 5×. A modern VCR configuration is implemented based on the proposed methodology, and simulation results verify the effectiveness of the modified approach in improving the accuracy of VI conversion.