Voltage-controlled oscillator

About: Voltage-controlled oscillator is a research topic. Over the lifetime, 23896 publications have been published within this topic receiving 231875 citations. The topic is also known as: VCO.

A millimeter-wave intra-connect solution

Abstract: A novel millimeter-wave Intra-Connect solution for short range, high speed, internal I/O connections in low-power logic 40 nm CMOS process is demonstrated. The system consists of a transmitter and a receiver that uses binary amplitude shift keying (ASK) modulation for a compact and power efficient design. The receiver realizes coherent demodulation using injection locking without a PLL or an external reference clock utilizing a path to inject the received signal into the VCO. The demonstrator achieves 11 Gb/s ASK data transmission over 14 mm using bond-wire antennas with a bit error rate (BER) of less than 10-11. The active footprint of the transmitter is 0.06 mm2 and the power consumption is 29 mW with an energy usage of 6.4 pj/bit per channel. The receiver occupies the active footprint of 0.07 mm2 and consumes 41 mW. The work shows the feasibility of the millimeter-wave Intra-Connect for high speed internal I/O connections.

Digital fractional phase detector

Abstract: A digital fractional phase detector is provided to realize a frequency synthesizer architecture that naturally combines transmitter modulation capability with a wideband all-digital PLL modulation scheme to maximize a digitally-intensive implementation by operating in a synchronous phase domain. Synchronous logic is provided across a digitally controlled VCO and is synchronous to the VCO output clock by implementing a timing adjustment in association with a reference calculation to allow a frequency control word to contain both channel information and transmit modulation information. The digital fractional phase detector is capable of accommodating a quantization scheme to measure fractional delay differences between the significant edge of the VCO output clock and a reference clock by using a time-to-digital converter to express the time difference as a digital word for use by the frequency synthesizer.

Design of Wide Tuning-Range CMOS VCOs Using Switched Coupled-Inductors

Abstract: Two designs of voltage-controlled oscillators (VCOs) with mutually coupled and switched inductors are presented in this paper to demonstrate that the tuning range of an LC VCO can be improved with only a small increase in phase noise and die area in a standard digital CMOS process. Particular attention is given to the layout of the inductors to maintain Q across the tuning range. In addition, different capacitive coarse-tuning methods are compared based on simulated and measured data obtained from test structures. Implemented in a 90 nm digital CMOS process, a VCO with two extra coupled inductors achieves a 61.9% tuning range with an 11.75 GHz center frequency while dissipating 7.7 mW from a 1.2 V supply. This VCO has a measured phase noise of -106 dBc/Hz at 1 MHz offset from the center frequency resulting in a higher figure-of-merit than other recently published VCOs with similar operating frequencies. In addition, the area overhead is only 30% compared to a conventional LC VCO with a single inductor.

The effect of varactor nonlinearity on the phase noise of completely integrated VCOs

Abstract: This work discusses variations in phase noise over the tuning range of a completely integrated 1.9-GHz differential voltage-controlled oscillator (VCO) fabricated in a 0.5-/spl mu/m bipolar process with 25-GHz f/sub t/. The design had a phase noise of -103 dBc/Hz at 100 kHz offset at the top of the tuning range, but the noise performance degraded to -96 dBc/Hz at 100 kHz at the bottom of the tuning range. It was determined that nonlinearities of the on-chip varactors, which led to excessively high VCO gain at the bottom of the tuning range, were primarily responsible for this degradation in performance. The VCO has a power output of -5 dBm per side. Calculations predict phase noise with only a small error and provide design insight for minimizing this effect. The oscillator core drew 6.4 mA and the output buffer circuitry drew 6 mA, both from a 3.3-V supply.

A dual-band coupled vco

Abstract: In a dual band capable voltage controlled oscillator VCO circuit comprising two voltage controlled oscillator units VCOl, VCO2, the voltage controlled oscillator units VCOl, VCO2 are synchronized and connected via at least two coupled transmission lines TLl, TL2, the transmission lines [TLl, TL2) are arranged to operate according to one of two modes to enable varying a combined inductance of the synchronized oscillator units VCOl, VCO2 and the oscillation frequency for the voltage controlled oscillator circuit VCO.