Broadband VCO based on source damping resistor

Abstract

The invention discloses a broadband VCO based on a source damping resistor. The broadband VCO belongs to the field of radio frequency integrated circuits and comprises LC-VCO cores of N working frequency bands, and N is an integer greater than or equal to 2; each LC-VCO core comprises an NMOS pair and a PMOS pair of which grid electrodes and drain electrodes are in cross coupling connection, a resonance network formed by connecting a switched capacitor array C-Tank, a variable capacitor and an L-C resonance network in parallel, and a source electrode damping resistor which is independently orsimultaneously connected with the source ends of the NMOS pair / PMOS pair, wherein drain electrodes of the NMOS pair and the PMOS pair are connected and then are connected with the resonance network; the L-C resonance network is used for carrying out frequency selection on an output signal and selecting a concerned fundamental frequency, the L-C resonance network comprises an inductor L and a capacitor C, and different LC-VCO cores have different inductors L and capacitors C. The source damping resistor is used for realizing loop gain reduction, designing an 8-shaped customized inductor, increasing the Q value of a resonant cavity, inhibiting harmonic components generated by a nonlinear effect, reducing flicker noise transmission and optimizing the phase noise performance of a VCO output signal.

Description

technical field [0001] The invention belongs to the field of radio frequency integrated circuits, and more specifically relates to a wideband VCO based on source damping resistance. Background technique [0002] VCO (Voltage Controlled Oscillator, Voltage Controlled Oscillator) is a general term for a type of oscillator whose output frequency is adjusted within a certain range by the input voltage. As an important module of frequency synthesizer, phase-locked loop and other clock generation circuits, VCO's phase noise directly affects the phase noise and jitter performance of the output clock. In the deep submicron process, with the progress of the process, the channel length of the MOS tube is continuously reduced, and the corner frequency of the flicker noise is continuously increased. The transistor flicker noise component in the phase noise has become the main factor affecting the VCO phase noise. [0003] There are many application scenarios for wideband VCOs, mainly i...

AI Technical Summary

Problems solved by technology

However, due to the introduction of drain damping resistors to the drains of the PMOS cross-coupling pair and the NMOS cross-coupling pair at the same time, it is difficult to start the oscillation of the VCO and the amplitude of the oscillation signal is too small.

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