An annotated guide to utilize ring-oscillators as thermal sensor in FPGA technology

Abstract

Ring Oscillators (ROs) are established as practical thermal sensors in Field Programmable Gate Array (FPGA) devices. Despite its proven technical usefulness in low-power design and thermal aspects of integrated circuit, a detailed standard procedure is not found in the literature. In this paper we present an optimized scheme including a detailed description of all elements and considerations, so those interested can quickly incorporate these ideas. Also, we show implementation, calibration and resources performing a characterization of a Xilinx Spartan 6 device.