A Test Structure for Analyzing Self-Heating Induced Distortion in On-Chip Current Sensing Resistors

This paper presents a test structure for a 27 mΩ diffusion current sensing resistor, designed to analyze distortion caused by self-heating in audio power amplifiers. A parallel Kelvin connection minimizes parasitic effects, reducing resistance error to 0.4% and temperature coefficient error to 0.7%. A diode-based temperature sensor array enables accurate measurement of temperature variations, allowing the characterization of HD3 with an inaccuracy of <1.4 dB. Eventually, the HD3 is compensated by at least 15 dB through the sensed average temperature.