A 5800-μm² Resistor-Based Temperature Sensor With a One-Point Trimmed Inaccuracy of ±1.2 °C (3σ) From −50 °C to 105 °C in 65-nm CMOS

Abstract

This paper describes a compact resistor-based temperature sensor intended for the thermal monitoring of microprocessors and DRAMs. It consists of an RC poly-phase filter (PPF) that is read out by a frequency-locked loop (FLL) based on a dual zero-crossing (ZC) detection scheme. The sensor, fabricated in 65 nm CMOS, occupies 5800 μm 2 and achieves moderate accuracy (±1.2 °C (3σ) inaccuracy) over a wide temperature range (−50 to 105 °C) after a one-point trim. This is 2 better than previous compact resistor-based sensors. Operating from 0.85 to 1.3 V supplies, it consumes 32.5 μA and achieves 2.8 mK resolution in a 1-ms conversion time, which corresponds to a resolution FoM of 0.26 pJ·K 2 . Index Terms-CMOS temperature sensor, resistor-based temperature sensor, RC poly phase filter, frequency-locked loop (FLL), dual zero-crossing (ZC) detection, one-point trim.

Ultra Miniature 1850 μm 2 Ring Oscillator Based Temperature Sensor

“…The curvature of the sensor is apparent from this figure. This curvature can be nulled by applying a 2nd order polynomial fix as is done in the prior-art [9], [10]. In a production environment, the curvature would be measured across several hundred units and then applied to the rest of the lot (millions).…”

“…The CTAT or PTAT nodes are then compared to Vref using an analog-to-digital converter. Resistors are also a good alternative to PNP-based sensors, although the sensing elements tend to be larger [9], [10]. MOS based sensors, which utilize the temperature dependence of the threshold voltage, Vth, have also been reported and these can be both small and very fast [11]- [14].…”

A Digital Improvement—Trimming a Digital Temperature Sensor with EEPROM Reprogrammable Fuses

“…The performances of the trimmed thermal sensor ( Figure 3 ) are compared with recently reported digital temperature sensors [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ] in Table 2 . The experimental results of 25 measured DTS samples are in good agreement with the majority of referred data [ 4 , 5 , 6 , 11 , 12 , 13 , 14 , 15 , 18 , 19 , 21 , 24 ], providing low inaccuracy in a wide temperature range.…”

“…A calibration procedure provides information about the accuracy of a thermal sensor [ 22 , 23 , 24 , 25 , 26 ]. Most circuits are calibrated to two well-defined temperature points, after which the circuit is adjusted to minimize the temperature error by trimming techniques [ 23 ].…”

“…Most circuits are calibrated to two well-defined temperature points, after which the circuit is adjusted to minimize the temperature error by trimming techniques [ 23 ]. A one-point calibration has the advantage of lower production costs [ 25 ].…”