A single-trim, highly accurate Colpitts-based frequency reference is presented. Our analysis shows that the Colpitts-topology outperforms the cross-coupled LC-topology in terms of temperature stability. Measurements on prototypes in a 0.13 µm high voltage CMOS SOI process were carried out from −50 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 3 wafers from the same batch. This is a 4x improvement over related single-trim stateof-the-art solutions. Frequency drift due to ageing, tested after a 6-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.

A single-trim, high accuracy frequency reference is presented. The Colpitts LC-oscillator topology reduces the temperature dependencies of the LC-tank quality factor on the oscillation frequency. With a fractional divider for frequency compensation it can serve as crystal-replacement. Measurements of the prototype (16 samples) in a 0.13µm high-voltage CMOS SOI process show ±120ppm accuracy from-50 to 170°C. The oscillator dissipates 3.5mW from a 2.5V supply and has 220ppm/V supply-sensitivity without supply regulation.

This paper presents a frequency reference system that combines high frequency accuracy and low power consumption using a single-point temperature trim and batch calibration. The system is intended as a low-cost fully integrated crystal oscillator replacement. In this system, the oscillation frequency of a power-efficient, but Process, Voltage, Temperature (PVT) and Lifetime (L) sensitive current-controlled ring oscillator (CCO) is periodically (re)calibrated by the well-behaved frequency stability of an untuned LC-based Colpitts oscillator (LCO), which is optimized for stability over PVTL. During the single-point room temperature factory trim, the frequency of the LCO is determined and the result is digitally stored. An on-chip calibration engine tunes the ring oscillator to the target frequency based on the LCO frequency, temperature sensor information and digitally stored trimming information, thus effectively improving the frequency stability of the ring oscillator. The relatively high-power LCO is heavily duty-cycled to minimize the overall power consumption. A prototype fabricated in a 0.13 µm highvoltage (HV) CMOS SOI process and assembled in a plastic package demonstrates an inaccuracy lower than ±93 ppm over a temperature range from −63 to 165 °C across 18 samples. The presented frequency reference system, including on-chip voltage regulators and a temperature sensor, occupies a chip area of 0.69 mm 2 and consumes about 64 µA from a single 3.3 V supply. The frequency error due to supply variation is roughly 92 ppm/V. The mean frequency shift due to aging, measured before and after a six-day storage bake at 175 °C, is only 52 ppm.