A high-linear low-power temperature-to-frequency converter with high robustness

A low-power temperature sensor circuit, consisting of a proportional-to-absolute-temperature (PTAT) current generator and a slew-rate controlled relaxation oscillator, is implemented in 65nm CMOS for on-chip temperature measurement. The PTAT current and triangular relaxation oscillator, both based on matched switched-capacitor (SC) modules, conduct a high-linear temperature-to-frequency conversion (TFC). The triangular clamping voltages are generated by a differential bandgap reference (BGR), which employs low-threshold and regular-threshold diodes simultaneously, suppressing process deviations and ensuring TFC robust. The proposed design achieves a temperature inaccuracy of -1 ~ +0.2°C across 0°C to 80°C under ±10% supply and 3σ process variations, after one-point calibration. The average power dissipation of 900nW is observed from a 0.8V supply.