16.4 0.6-to-1.0V 279μm2, 0.92μW temperature sensor with less than +3.2/-3.4°C error for on-chip dense thermal monitoring

On-chip temperature sensors are key building blocks for the thermal management of multi-core microprocessors. The sensors are embedded at multiple locations in a microprocessor and monitor temperatures that are used to manage the operation of the microprocessor under local and global thermal constraints. While existing sensors achieve impressive area and accuracy, emerging technology trends such as multi-core architectures, 3D integration, tri-gate devices, and low-voltage operation demand even better sensors with difficult-to-meet requirements. Those requirements are three-fold: 1) Sensors need to be area efficient. By increasing the number of cores and hot spots, there are more locations that require thermal monitoring. To reduce the overhead, the sensor footprint needs to be minimized. A compact footprint is further critical for design flexibility, as the exact sensor locations (e.g. near hot spots) are often only identified in later stages of the design process [1]. 2) Sensors need to have low calibration cost, while achieving sufficient accuracy. The requirements of <;8°C in absolute inaccuracy and <;3°C in relative inaccuracy have been outlined in [2]. 3) Finally, the sensors need better supply voltage (V_DD) scalability. Sub-1V operation for digital systems is being explored to reduce power. The conventional sensors often cannot operate below 1V, necessitating additional power distribution or regulation. Sub-1V scalability eliminates such overhead.