A Single-Trim Frequency Reference Achieving ±120 ppm Accuracy From −50 °C to 170 °C

Abstract

A single-trim, highly accurate Colpitts-based frequency reference is presented. Our analysis shows that the Colpitts-topology outperforms the cross-coupled <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> -topology in terms of temperature stability. Measurements on prototypes in a 0.13- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> high-voltage CMOS silicon on insulator (SOI) process were carried out from −50 °C to 170 °C. Based on sample-specific single room temperature trim and batch calibration, our frequency reference achieves an accuracy of ±120 ppm for 16 samples from a single wafer utilized for extracting the batch-calibration polynomial and ±300 ppm for 48 samples across three wafers from the same batch. This is a 4 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> improvement over related single-trim state-of-the-art solutions. Frequency drift due to aging, tested after a six-day 175 °C storage, is below 100 ppm. The oscillator core dissipates 3.5 mW from a 2.5-V supply and has 220-ppm/V supply sensitivity without supply regulation.