Low-power oscillator with memory reduction tail transistors for 2.4 GHz ISM band applications

This paper presents a fully integrated low-power CMOS LC voltage-controlled oscillator (VCO) by using complementary cross-coupled pair and the memory reduction of the tail current source. The idea of the tail current source memory reduction is applied for the VCO. The flicker noise of the metal oxide semiconductor field effect transistors (MOSFETs) can be further suppressed by such switched design of the tail currents, thus improving the phase noise of the VCO. Meanwhile, the current driving capability is sufficiently achieved under low overall power consumption by using NMOS for the tail current source. This integrated circuit is fabricated by using the TSMC T18 1P6M process. Compared with other VCOs with use of the tail current framework, our proposed performance reached figure of merit (FOM) of 185.96 dB after optimization, the measured phase noise are -123.26 and -144.17 dBc/Hz, at 1 MHz and 10 MHz frequency offset, respectively, and the power consumption of the VCO core is 3.096 mW.