Development of a Highly Linear Temperature Sensor and Voltage Reference

摘要

Voltage reference is an essential part in many mixed-signal and analog applications. The requirements are stable over process, power supply voltage, and temperature variations. Particularly, in the system-on-a-chip (SoC) era, a chip often contains millions of transistors. Its power dissipation increases and consequently the temperature raises. This issue is especially emphasized in circuits operating at high frequency. A chip with built-in temperature sensor assures the system reliability by preventing deadly faults due to excessive chip temperature. Based on the CMOS PTAT (proportional to absolute temperature) principle, a voltage reference integrated with temperature sensor is implemented in a fully digital process. In the temperature range from 20 ℃ to 120 ℃, the experimental results show that the voltage reference can provide temperature-stable voltage around 0.717 V and its associated temperature sensor has the sensitivity 2.3 mV/℃ with above 95% linearity, almost independent of the variation of supply voltage.