Design and Integration of Digital Thermal Sensors

In this paper, the design and integration of a digital thermal sensor (DTS) is presented inside a System On Chip (SOC). This work proposes a bandgapbased voltage reference with Analog-to-Digital-Converter (ADC) to realize a DTS with improved accuracy and fast temperature readouts. The DTS has a temperature readout accuracy of $+1.5 \mathrm{C}-3 \mathrm{C}$ across a wide range of temperatures. We present the analog integration challenges that SOCs having multiple supply domains face in integrating the DTS and the techniques used to overcome them. Furthermore, we showcase how we minimize the noise coupling and improve the speed on the sensitive routes used to read temperatures. We believe our work is valuable to the SOC design community and will help address the issue of steep thermal gradients present in the latest process nodes and also drive down the thermal cooling costs by using proactive measures.