An all CMOS temperature sensor for thermal monitoring of VLSI circuits

Power and thermal considerations are becoming limiting factors for submicron circuits as technology scales down. In order to detect abnormal temperature changes so as to detect defects on chip, and increase reliability and service life of devices, an all CMOS temperature sensor for submicron circuits' test is proposed. A current proportion to absolute temperature is generated for achieving linear temperature-dependent voltage and zero temperature coefficient voltage. A voltage-to-pulse generator instead of voltage or current analog-to-digital converter is utilized for translating voltage into a pulse with width proportional to the measured temperature. The SMIC 0.18um model was chosen for design. The proposed smart sensor was measured to have an error of -1.0 similar to 1.0 degrees C at most after two point calibration over the full rang of -50 similar to 150 degrees C for thermal testing or self-heat monitoring. The power consumption is 135.9uw at a sampling rate of 100 samples per second. This temperature sensor increases the system reliability by detecting heat points and predicting eventual faults caused by excessive chip temperature.