This paper describes a compact, energy efficient, resistor-based temperature sensor that can operate over a wide temperature range (-55 °C-125 °C). The sensor is based on a Wheatstone bridge (WhB) made from silicided poly-silicon and non-silicided poly-silicon resistors. To achieve both area and energy efficiencies, the current output of the WhB is digitized by a continuous-time zoom analog-to-digital converter (ADC). Implemented in a standard 180-nm CMOS technology, the sensor consumes 52 μA from a 1.8-V supply and achieves a resolution of 280 μKrms in a 5-ms conversion time. This corresponds to a state-of-the-art resolution figure-of-merit (FoM) of 40 fJ · K². After a first-order fit, the sensor achieves an inaccuracy of ±,0.12 °C (3σ) from -55 °C to 125 °C.
- Continuous-time delta–sigma modulator ( CTΔ Σ M)
- energy efficiency
- non-linearity correction
- smart sensors
- temperature sensor