A 0.53pJK27000μm2resistor-based temperature sensor with an inaccuracy of ±0.35°C (3σ) in 65nm CMOS
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Abstract
In microprocessors and DRAMs, on-chip temperature sensors are essential
components, ensuring reliability by monitoring thermal gradients and hot
spots. Such sensors must be as small as possible, since multiple
sensors are required for dense thermal monitoring. However, conventional
BJT-based temperature sensors are not compatible with the sub-1V supply
of advanced processes. Subthreshold MOSFETs can operate from lower
supplies, but at high temperatures their performance is limited by
leakage [1,2]. Thermal diffusivity (TD) sensors achieve sub-1V operation
and small area with moderate accuracy, but require milliwatts of power
[3]. Recently, resistor-based sensors based on RC WienBridge (WB)
filters have realized high resolution and energy efficiency [4,5].
Fundamentally, they are robust to process and supply-voltage scaling.
However, their readout circuitry has been based on continuous-time (CT)
ΔΣ ADCs or frequency-locked loops (FLLs), which require precision analog
circuits and occupy considerable area (>0.7mm
2
).