A Sub-50 µm2, Voltage-Scalable, Digital-Standard-Cell-Compatible Thermal Sensor Frontend for On-Chip Thermal Monitoring

This paper presents an on-chip temperature sensor circuit for dynamic thermal management in VLSI systems. The sensor directly senses the threshold voltage that contains temperature information using a single PMOS device. This simple structure enables the sensor to achieve an ultra-compact footprint. The sensor also exhibits high accuracy and voltage-scalability down to 0.4 V, allowing the sensor to be used in dynamic voltage frequency scaling systems without requiring extra power distribution or regulation. The compact footprint and voltage scalability enables our proposed sensor to be implemented in a digital standard-cell format, allowing aggressive sensor placement very close to target hotspots in digital blocks. The proposed sensor frontend prototyped in a 65 nm CMOS technology has a footprint of 30.1 µm2, 3σ-error of ±1.1 °C across 0 to 100 °C after one temperature point calibration, marking a significant improvement over existing sensors designed for dynamic thermal management in VLSI systems.