Implementation of a Built-in Temperature Sensor Using 65 nm 1.2 V Complementary Metal Oxide Semiconductor

This chapter proposes a built-in temperature sensor designed, and implemented, in deep submicron technologies for online thermal testing and monitoring of the Very Large Scale Integrated (VLSI) circuits. The temperature sensor utilizes the temperature coefficient for the threshold voltage of a metal oxide semiconductor (MOS) transistor. To minimize the influence of the operating point of an MOS transistor, it exploits “diode-connected” devices and very small aspect ratio device to detect the temperature variation. The sensor also delivers an extremely concise digital signal output based on a voltage-controlled relaxation oscillator. The simulation results show that the predicted temperature variation of the sensor is within 1 °C between −7 and +125 °C. The power dissipation is about 180 μW. And the number of the transistors needed is quite small. This sensor covering a small area of 135.8 × 65.15 μm² has been implemented in 65 nm complementary metal oxide semiconductor (CMOS) process. The function of the sensor has been proved functioning well between +30 and +100 °C with a 1.2 V supply voltage.