摘要:
A capacitive-degeneration double cross-coupled voltage-controlled oscillator is provided. The capacitive-degeneration double cross-coupled voltage-controlled oscillator includes a main cross-coupled oscillating unit including an oscillation transistor pair cross-coupled to first and second output nodes of a resonating unit to perform an oscillation operation; and an auxiliary cross-coupled oscillating unit including a positive-feedback transistor pair cross-coupled to the first and second output nodes and the transistor pair of the main cross-coupled oscillating unit and a degeneration capacitance connected between emitters of the positive-feedback transistor pair so as to increase a negative resistance of the main cross-coupled oscillating unit. Accordingly, it is possible to increase a maximum attainable oscillation frequency and to decrease an input capacitance.
摘要:
Provided is a colpitts quadrature voltage controlled oscillator capable of obtaining quadrature orthogonal signals using a quadrature combination between a base and a collector of each transistor, without using an additional circuit such as a coupled transistor, a coupled transformer, a multiphase RC filter, etc. Accordingly, since nonlinearity, increased phase noise, a decrease in the Q-factor of an LC resonator, and increased power consumption can be avoided, a colpitts quadrature voltage controlled oscillator that has low phase noise, low electric power consumption, and a compact size can be implemented.
摘要:
Provided is a colpitts quadrature voltage controlled oscillator capable of obtaining quadrature orthogonal signals using a quadrature combination between a base and a collector of each transistor, without using an additional circuit such as a coupled transistor, a coupled transformer, a multiphase RC filter, etc. Accordingly, since nonlinearity, increased phase noise, a decrease in the Q-factor of an LC resonator, and increased power consumption can be avoided, a colpitts quadrature voltage controlled oscillator that has low phase noise, low electric power consumption, and a compact size can be implemented.
摘要:
A capacitive-degeneration double cross-coupled voltage-controlled oscillator is provided. The capacitive-degeneration double cross-coupled voltage-controlled oscillator includes a main cross-coupled oscillating unit including an oscillation transistor pair cross-coupled to first and second output nodes of a resonating unit to perform an oscillation operation; and an auxiliary cross-coupled oscillating unit including a positive-feedback transistor pair cross-coupled to the first and second output nodes and the transistor pair of the main cross-coupled oscillating unit and a degeneration capacitance connected between emitters of the positive-feedback transistor pair so as to increase a negative resistance of the main cross-coupled oscillating unit. Accordingly, it is possible to increase a maximum attainable oscillation frequency and to decrease an input capacitance.
摘要:
A wide-band multimode frequency synthesizer using a Phase Locked Loop (PLL) is provided. The multiband frequency synthesizer includes a multimode prescaler, a phase detector/a charge pump, a swallow type frequency divider, and a switching bank LC tuning voltage-controlled oscillator having wide-band and low phase noise characteristics. The multimode prescaler operates in five modes and divides a signal up to 12 GHz. The wide-band frequency synthesizer can be used in various fields such as WLAN/HYPERLAN/DSRC/UWB systems that operate in the frequency range from 2 GHz to 9 GHz. The wide-band multimode frequency synthesizer includes a frequency/phase detector for comparing a frequency and phase of a reference high-frequency signal with a frequency and phase of a feedback high-frequency signal; a charge pump for producing an output current corresponding to the result of the comparison performed by the frequency/phase detector; a loop filter for producing an output voltage corresponding to an accumulated value of the output current of the charge pump; a voltage-controlled oscillator for generating an oscillation signal having a frequency corresponding to the output voltage of the loop filter; and a variable frequency divider for dividing an output signal of the voltage-controlled oscillator by a designated integer value, and outputting the result as a feedback signal, wherein at lease two of an amount of unit pumping charges of the charge pump, an RLC value of the loop filter, an RLC value of the voltage-controlled oscillator, and a divisor value of the variable frequency divider are controlled according to a band.
摘要:
Provided is an LC resonance voltage-controlled oscillator (VCO) used for a multi-band multi-mode wireless transceiver. In order to generate a multi-band frequency, a capacitor bank and a switchable inductor are included in the LC resonance voltage-controlled oscillator. The LC resonance voltage-controlled oscillator employs an adjustable emitter-degeneration negative resistance cell in place of tail current sources in order to compensate for non-uniform oscillation amplitude caused by the capacitor bank and prevent the degradation of a phase noise due to the tail current sources. The LC resonance voltage-controlled oscillator includes an inductor providing an inductance element partially determining the frequency of an oscillation wave; a discrete capacitor bank providing a capacitance element partially determining the frequency of the oscillation wave and being discretely determined by a control bit signal; and a discrete negative resistance cell providing a negative resistance element that is discretely determined by the control bit signal, to keep the amplitude of the oscillation wave constant.
摘要:
A differential voltage controlled oscillator (VCO) employed in a frequency synthesizer used as a local oscillator of a wireless communication on-chip transmitter/receiver is provided. More particularly, a differential current negative feedback VCO equipped with a current-current negative feedback circuit that suppresses low- and high-frequency noise is provided.A differential current negative feedback VCO includes a resonator determining oscillation frequency, and an oscillator generating negative resistance. In the oscillator of the differential current negative feedback VCO, transistors Q1 and Q2 form a cross-coupled pair, and negative resistance is generated by positive feedback of the cross-coupled pair. And, transistors Q1 and Q3 together with an emitter resistor and a capacitor form a current negative feedback part, and transistors Q2 and Q4 together with an emitter resistor and a capacitor form another current negative feedback part which is disposed opposite to a resonator. Thus, the VCO operates differentially.In the oscillator of the differential current negative feedback VCO, emitter noise currents generated by base noise voltages of Q1 and Q2 induced by low- and high-frequency noise sources in the bases of Q1 and Q2 are sampled by emitter resistors, amplified through bases of Q3 and Q4, and thus return to the bases of the Q1 and Q2 and suppress the base noise voltages. Measurement of the phase noise of the differential current negative feedback VCO reveals a phase noise reduction of approximately 25 dB compared to a conventional differential VCO.
摘要:
Provided is a voltage-controlled oscillator (VCO) using a current feedback network for use in a wireless communication terminal. The voltage-controlled oscillator has high input impedance and low output impedance, so that a degree of isolation from the external load is excellent, thereby preventing degradation of the Q-factor by the load in overall oscillation circuit. In the voltage-controlled oscillator of the present invention, an LC resonator is provided to generate positive feedback, and negative resistance may be obtained at a wider frequency range by tuning a varactor of the LC resonator. And a boosting inductor is inserted into the positive feedback loop to have a greater negative resistance, therefore it is possible to prevent a problem in which the oscillation does not occur due to the parasitic resistance components generated during circuit fabrication.
摘要:
A germanium semiconductor device and a method of manufacturing the same are provided. The method includes the steps of: forming an isolation layer on a substrate using a shallow trench; forming a silicon-nitride layer on the substrate, and selectively etching the silicon nitride layer to expose source and drain regions; injecting impurities onto a surface of the substrate over the exposed source and drain regions using delta-doping to form a delta-doping layer; selectively growing a silicon germanium layer containing impurities on the delta-doping layer; rapidly annealing the substrate and forming source and drain regions by diffusion of the impurities; depositing an insulating layer on the entire surface of the substrate; etching the insulating layer and forming source and drain contact parts to be in contact with source and drain terminals; depositing metal over the insulating layer having the source and drain contact parts thereon and forming a metal silicide layer; and after forming the silicide layer, forming the source and drain terminals to be in contact with the silicide layer. Accordingly, the source and drain regions having a shallow junction depth may be ensured by forming the source and drain regions through annealing after delta-doping and selectively growing the silicon germanium layer containing high-concentration impurities. Also, the germanium silicide layer is stably formed by the silicon germanium layer grown in the source and drain regions, and thus contact resistance is lowered and driving current of the device is improved.
摘要:
Provided are a high-quality CMOS image sensor and a photo diode, which can be fabricated in sub-90 nm regime using nanoscale CMOS technology. The photo diode includes: a p-type well; an internal n-type region formed under a surface of the p-type well; and a surface p-type region including a highly doped p-type SiGeC epitaxial layer or a polysilicon layer deposited on a top surface of the p-type well over the internal n-type region. The image sensor includes: a photo diode including an internal n-type region and a surface p-type region; a transfer transistor for transmitting photo-charges generated in the photo diode to a floating diffusion node; and a driving transistor for amplifying a variation in an electric potential of the floating diffusion node due to the photo-charges. The image sensor further includes a floating metal layer for functioning as the floating diffusion node and applying an electric potential from a drain of the transfer transistor to a gate of the driving transistor.