1,720,979 research outputs found
System and method for a voltage controlled oscillator
No full textIn accordance with an embodiment, an oscillator includes a tank circuit and an oscillator core circuit having a plurality of cross-coupled compound transistors coupled to the tank circuit. Each of the plurality of compound transistors includes a bipolar transistor and a field effect transistor (FET) having a source coupled to a base of the bipolar transistor
Fast hopping frequency synthesizer
No full textApparatus and systems for synthesizing frequencies for use in a fast hopping wireless communications system. A frequency synthesizer comprises a plurality of oscillators with each oscillator having a first input coupled to a reference clock frequency signal, and a signal selector having a control signal input and a plurality of reference clock inputs with each reference clock input coupled to an output from an oscillator. Each oscillator produces a reference frequency that is a harmonic of a reference clock frequency of the reference clock frequency signal, and the signal selector couples a reference clock input to an output based on a control signal provided by the control signal input
A 17 GHz All-npn Push-Pull Class-C VCO
No full textA SiGe BiCMOS push-pull class-C VCO operating at 17 GHz and making use of only npn transistors is presented. A magnetic transformer is used to set positive feedback around a common-collector differential pair and implement the push-pull operation. This allows to halve the bias current for a given amplitude of oscillation, while using just one type of active devices. The oscillator features a phase noise as low as -116 dBc/Hz at 1 MHz offset, while drawing 13.7 mA from the 3.3 V supply. The tuning range is 15%
Analysis and Design of a 17-GHz All-npn Push-Pull Class-C VCO
No full textA push-pull oscillator topology that uses only one type of active device is proposed in this article. A magnetic transformer is leveraged to set positive feedback around a common-collector differential npn transistor pair, implementing the push-pull operation. This results in half the bias current for a given amplitude of oscillation, compared to more standard oscillator topologies. A thorough phase noise analysis of the circuit is carried out, emphasizing the crucial role of the magnetic transformer in the circuit operation and noise optimization. Proof-of-concept prototypes implemented in a 130-nm SiGe BiCMOS technology operate at 17 GHz and show a phase noise as low as -116 dBc/Hz at 1-MHz offset, while drawing 13.7 mA from the 3.3-V supply. The tuning range is 15%. While the circuit is demonstrated in SiGe BiCMOS technology, it lends itself equally well to implementations in other technologies where only one fast device is available, such as SiGe HBT, InP HBT, and GaN HEMT
A 15.5–39GHz BiCMOS VGA with phase shift compensation for 5G mobile communication transceivers
No full textA BiCMOS VGA for the emerging 5G mobile communication systems operates from 15.5 to 39GHz with a maximum 17 dB gain, features 43 dB gain variation, and, due to the use of compensation circuits, it shows a reduced phase shift variation, namely 3◦ up to 30GHz for a gain variation of 23 dB. The VGA NF is 3.6-9 dB, its IIP3 is -1 dBm, while the power consumption is 104mW
A 12GHz 22dB-gain-control SiGe bipolar VGA with 2° phase shift variation
No full textA 12 GHz VGA is presented that shows a gain control from -9 dB to 13 dB in a linear-in-dB fashion. As the gain is changed, the phase shift over the entire 10 to 14.4GHz bandwidth varies as little as <= 2 degrees due to a compensation circuitry that reduces the input-output phase shift sensitivity to gain variations. The VGA prototypes, implemented in a SiGe bipolar technology, show a noise figure of 5.1 dB, an IIP3 of -3dBm, and a power consumption of 83mW
Class-J SiGe X-Band Power Amplifier Using a Ladder Filter-Based AM-PM Distortion Reduction Technique
No full textIn this paper, a class-J power amplifier for operation in the X-band realized in SiGe bipolar technology is presented. The proposed design combines the high efficiency of class-J operation with solutions to mitigate AM-PM distortion down to a level compatible with high spectral efficiency modulation schemes like 64-QAM. The design of a transformer-based output matching network and the trade-off between efficiency and pure class-J operation related to a non-ideal second harmonic termination are discussed. The main sources of AM-PM distortion are identified in the base-emitter and collector-based bipolar junction transistor capacitance variation with power level and solutions that make the design less sensitive to these impairments are proposed. Linear MIM capacitors are used at the power amplifier (PA) core output to realize the proper class-J second harmonic termination, while an input matching network based on a Bessel ladder filter is adopted to make the signal phase at the PA core input less sensitive to base-emitter capacitance variation. A class-J PA previously designed for maximum power-added efficiency (PAE) is used as a reference throughout the paper to highlight the trade-off's entailed by AM-PM distortion reduction. The designed PA features a peak gain of 15 dB at 10 GHz and 8-to-12 GHz -3 dB bandwidth. The saturated power is 22 dBm with a 33% PAE, while the output p1dB is 19 dBm. The AM-PM distortion at p1dB is 5 degrees
SiGe BiCMOS VCO with 27% tuning range for 5G communications
No full textA SiGe BiCMOS VCO with a transformer-coupled varactor operating from 12 to 15.9GHz is presented. The oscillator core features a phase noise as low as -117 dBc/Hz at 1MHz offset from the 14.2GHz carrier while drawing 8mA from the 3.3V supply. The VCO shows a state-of-the-art FoMT of -190 dBc/Hz. The trade-off for the technology selection is described in the introduction. The oscillator is tailored to the communication systems for the upcoming 5G applications. New radios that will operate from 6GHz to as high as 100 GHz may be needed
A quad-core 15GHz BiCMOS VCO with -124dBc/Hz phase noise at 1MHz offset, -189dBc/Hz FOM, and robust to multimode concurrent oscillations
No full textThe relentless development of next-generation communication and radar systems sets increasingly stringent requirements on the spectral purity of local oscillators. Decreasing phase noise is crucial to support efficient modulation formats with large symbol constellations, as well as to enable innovative radar applications, e.g., anti-collision, gesture recognition, and medical imaging. To minimize phase noise, bipolar transistors offer some advantages over ultra-scaled CMOS: higher supply voltage (thus larger oscillation amplitudes), lower 1/f noise, higher-Q passives (due to higher resistivity substrate and, possibly, thicker metals), and higher f T , f max for a given technology node, which results in a cost advantage for a variety of medium-volume applications (e.g., infrastructure transceivers). For a given supply voltage, a tank showing a smaller resistance at resonance yields lower phase noise. As a result, the minimum phase noise achievable by a single voltage-controlled oscillator (VCO) is ultimately bounded by the smaller realizable inductor displaying the highest Q. To achieve significantly lower phase noise levels, bilaterally coupling N oscillators [1-3] is a viable option. However, to fully preserve the 10log(N) phase-noise advantage, while avoiding undesired multi-tone concurrent oscillations, the coupling network must be carefully designed. This work presents a quad-core bipolar VCO achieving phase noise as low as -124dBc/Hz at 1MHz offset from the 15GHz carrier, -189dBc/Hz figure-of-merit (FOM), and 16% tuning range. Insights are given into the design of the resistive network employed to couple the four oscillators, a key element in achieving the reported performance
A 21GHz 20.5%-tuning range Colpitts VCO with −119 dBc/Hz phase noise at 1MHz offset
No full textA SiGe BiCMOS Colpitts VCO with a transformer-coupled varactor operating from 18.8 to 23.1 GHz is presented. The Colpitts topology is leveraged to trade a slight degradation in the oscillator figure-of-merit for very low phase noise. The oscillator features a state-of-the-art phase noise of -119.4 dBc/Hz at 1 MHz offset from the carrier, while drawing 17.5 mA from the 4 V supply. The oscillator FoM is -188 dBc/Hz. The VCO also shows a wide 20.5% tuning range, which results in a FoMT = -194 dBc/Hz
- …
