A Temperature Compensation Voltage Controlled Oscillator Using a Complementary to Absolute Temperature Voltage Reference

Abstract

T his paper presents a temperature compensation voltage controlled oscillator (VCO) based on Cross-Coupled pair and Colpitts structures which is suitable for military fields. Also, two inductors have been used for increasing the negative conductance. By using this method, start-up condition has been improved. Two varactors and a simple capacitor bank are applied for covering a wide tunning range. T he VCO has been designed and simulated in T SMC 0.18 µm CMOS technology.To compensate the frequency drift over a temperature range, MOS varactors are used and biased with a complementary to absolute temperature (CTAT) voltage reference. This CT AT voltage reference has been applied to two varactors and decreased the frequncy drift over temperature range. By using this technique, the proposed VCO can achieve a very stable frequency of 11.5 PPM/°C at 24.35 GHz over a temperature range of-40~120 °C. Simulation results also show the VCO covers the frequency range of 23.75~24.8 GHz. T he simulated phase noise of center frequency is-102.6 dBc/Hz at 1 MHz offset frequency. T he VCO consumes 10.4 mW DC power under 1.8 V supply voltage. The figure of merit of the VCO is-179.8 after compensating.

Ultra Low Power Temperature Compensated Complementary Metal Oxide Semiconductor Ring Oscillator in Subthreshold

“…Considering the type of application that oscillator is designed for, the appropriate compensation technique is developed. For example, as reported by Katebi et al [10] the main challenges in the military fields are the precision of the oscillation frequency as well as its thermal stability. To combat these challenges a hybrid cross-coupled Colpitts VCO is presented by Katebi et al [10], in which the varactors are driven by CTAT voltages.…”

“…For example, as reported by Katebi et al [10] the main challenges in the military fields are the precision of the oscillation frequency as well as its thermal stability. To combat these challenges a hybrid cross-coupled Colpitts VCO is presented by Katebi et al [10], in which the varactors are driven by CTAT voltages. Although the temperature coefficient (TC) of the VCO and its phase noise are acceptable, its high-power consumption and chip area (due to use of inductors) are not appropriate for biomedical devices.…”

“…So, in order to achieve desirable frequency stability, using compensation techniques [4,5] is mandatory. Thus, several researches have been devoted to effective compensation of the CMOS oscillators [4,[6][7][8][9][10][11][12][13]. Considering the type of application that oscillator is designed for, the appropriate compensation technique is developed.…”