A Temperature- and Aging-Compensated RC Oscillator With ±1030-ppm Inaccuracy From40 °C to 85 °C After Accelerated Aging for 500 h at 125 °C

Abstract

This article presents a temperature-and agingcompensated RC oscillator (TACO) in which the long-term drift of the main oscillator is compensated by periodically locking its frequency to that of the less-aged reference oscillator. To improve the long-term stability of the TACO, it employs techniques, such as the use of higher activation energy (E a ) resistors, switched dual RC branches to mitigate stress from dc-current-induced electromigration (EM), and duty cycling to slow down the aging rate of the reference oscillator. Using the proposed techniques, a prototype 100-MHz RC oscillator fabricated in a 65-nm CMOS process achieves an inaccuracy of ±1030 ppm from −40 • C to 85 • C after 500 h of accelerated aging at 125 • C, with 5.1-ps rms period jitter and a power efficiency of 1.4 µW/MHz.