Also, a new digitally controlled oscillator dco structure for low power, small area is presented and its frequency range is from 200 mhz to 750 mhz with a supply voltage 1. One digital controlled oscillator dco with rctype characteristics one crystal oscillator used for lowfrequency crystals watch crystals, e. Dcos were designed to overcome the tuning stability limitations of early vco designs. The measured pkpk jitter and rms jitter are 14ns and 2. Digitally controlled oscillator wiley online library. An ultralowpower 15bit digitally controlled oscillator. Highresolution mmwave digitally controlled oscillator in. The output of the dco is usually a high frequency signal, noted osc in the. A study on digitally controlled oscillators for all.
Submicron cmos process fully digital control of oscillating frequency lc tank oscillator core open. It is the responsible for most of the power consumption and it is extremely susceptible to process, supply voltage and temperature pvt. The dco is composed of four differential delay cells and can achieve linear tuning over a wide frequency range. Frequency tuning is achieved through digital control of an ir. Pdf a first rf digitallycontrolled oscillator for mobile phones. Design of low power 6bit digitallycontrolled oscillator dco mohammad anisur rahman, habibah binti mohamed, mamun bin ibne reaz, sawal hamid md ali, and wan mimi diyana wan zaki department of electrical, electronic and systems engineering faculty of engineering and built environment. However analog pll are sensitive to process parameters variations and must be redesigned with changing technology 2. Dds is a technique used for generating an analog waveform, generally of a sinusoidal wave shape, from a time varying signal in its digital form and a dac. The msp430 is a popular microcontroller, and on board is a neat little clock source, a digitally controlled oscillator, or dco. Since the power consumption of truesinglephaseclock tspc dividers is. Pdf here, two new designs of cmos digitally controlled oscillators dco for low power application have been proposed. This oscillator can be used for everything from setting baud rates. In this paper, an ultra low power 15bit digitally controlled oscillator is proposed. The devices default startup frequency is specified in the ordering code.
The dco achieves frequency quantization step of 300 hz without any dithering. Design of a 8bits digitally controlled oscillator with low power. It was a challenge to achieve a low voltage, low power, and high resolution simultaneously. Pdf a novel digitally controlled oscillator dcobased architecture for frequency synthesis in wireless rf applications is proposed and demonstrated find. Design of low power 6bit digitallycontrolled oscillator. A digitally controlled oscillator dco includes a current generator which generates an electric current having a magnitude corresponding to an input signal, and a digitally controlled oscillating unit which generates an oscillating frequency based on an inductance which varies according to the magnitude of the electric current generated by the current generator. A lowpower digitally controlled oscillator for all. This programmable device supports any frequency, 1220 mhz, along with any combination of voltage 1. A low power digitally controlled oscillator using 0. Design of low power 6bit digitallycontrolled oscillator dco. The name is analogous with voltagecontrolled oscillator. It is reliable, uses standard components, gives a good sine wave, and is fairly immune to the type of op amp around which it is designed. Digitally controlled oscillator for wimax in 40 nm author.
W digitally controlled oscillator based on hysteresis delay cell topologies for wban applications. This isin this paper, a new differential delay cell has been proposed and 16bit digital controlled oscillator is designed. In analog pll, the oscillation frequency is controlled by a voltage input which is in analog form. Digitally controlled clock generators are less sensitive and easier to implement.
Design of high frequency, low phase noise lc digitally. The evolution of technology into deep submicron domains leads to increasingly complex timing closure problems to design multiprocessor systems. Index termsalldigital phaselocked loop adpll, cellbased hardware description language, digitally controlled oscillator. Robert bogdan zyxwvu zyx a first rf digitallycontrolled oscillator for mobile phones staszewski, chihming hung, nathen barton, mengchang lee, and. Optimization of digitally controlled oscillator with low power. A tunable oscillator suitable for use in a frequency synthesizer of a transceiver is controlled by varying one or more parameters associated with the oscillator.
The proposed circuit has a simple structure, and the power consumption of this. Besides, three di erent oscillator topologies are compared, and an optimized oscillator structure is used to improve dco gure of merit. This paper presents the design, simulation, and measurements of a low power, low phase noise 10. Utilizing a new capacitive load, the new dco is capable of producing much higher output frequencies than existing dcos. Us5739725a digitally controlled oscillator circuit. The proposed dco is designed based on a segmental coarsetuning stage and employs hysteresis delay cell hdc and digitally controlled varactor dcv in the finetuning stage. Digitally controlled oscillator for alldigital frequency. A novel digitally controlled oscillator dcobased architecture for frequency synthesis in wireless rf applications is proposed and demonstrated. A portable highfrequency digitally controlled oscillator. Index termscmos digital integrated circuits ics, digital control, digitally controlled oscillator dco, mos varactor, voltagecontrolled oscillators vcos. Other imperfections of analog circuits are compensated through digital means. Robert bogdan zyxwvu zyx a first rf digitallycontrolled oscillator for. Index termsalldigital phaselocked loop adpll, cellbased hardwaredescription language, digitally controlled oscillator. Sit3521 preliminary 1 to 340 mhz elite platform i cspi.
Ring oscillator, digitallycontrolled oscillator, digitaltoanalog. It deliberately avoids any use of an analog tuning voltage control line. To implement a wide frequency range adpll, the dco must have a wide oscillation frequency. Performance of the dco is verified through a novel all digital phaselocked loop adpll designed with a. Many thanks to ken maggio, manager of the rfcmos group in texas instruments for his feedback and daytoday activities to make this testchip a success. Digitally controlled oscillator dcobased architecture for rf frequency synthesis in a deepsubmicrometer cmos process. A digitally controlled oscillator or dco is used in synthesizers, microcontrollers, and softwaredefined radios. Cmos digitally controlled oscillator dco design is presented.
The main goal of this work was to design the lc dco using a mature. Voltage controlled oscillators tuning a voltage controlled oscillator vco is an oscillator whose frequency can be varied by a voltage or current. Design of gigahertz tuning range 5 ghz lc digitally. This form of oscillators is called voltage controlled oscillator vco. The digitally controlled oscillator dco is the block that dominates the overall performance of the adpll. Dcos can achieve a high resolution at the cost of high power consumption. Digitally controlled oscillator for mmwave frequencies. Digitally controlled oscillator for adflls 5 to use a voltage controlled ring oscillator and a digitaltoanalog converter this implementation is depicted in the. One implementation of the dco uses variable delay ring oscillators which require a large number of delay elements in order to obtain desirable frequency. A digitally controlled oscillator in a 90 nm digital cmos process for mobile phones, ieee journal of solidstate circuits 4011.
In particular, a digital control signal affects one or more of the capacitances of the oscillator, the bias voltage of the oscillator, the supply voltage, or the bias current of the oscillator. Analysis of a digitally controlled wienbridge oscillator abstract. Digital controlled oscillator dco is most critical block in. One natural alternative is to resort to the globally asynchronous, locally synchronous paradigm gals. The dco is promoted with an effective fine tuning bank based on a binary. Dcos with metal oxide semiconductor mos varactors consume low power, but their resolution is limited. Digitally controlled crystal oscillator mis2007927 the 2 digitally con7 trolled crystal oscillator dcxo combines the frequency stability of a crystal oscillator source with the flexibility of direct digital synthesis dds in a temperature controlled housing to provide a highly accurate output signal. Thus cmos digitally controlled oscillator was designed and analyzed for 416 bits,where 4bits dco with width of 3. Frequency tx or rx range voltage tuning range linear tuning nonlinear tuning fig. A digitally controlled oscillator for adpll application. The digitally controlled oscillator of 8bit pic microcontrollers offers a wide range of selectable frequencies for the system and peripheral clock sources. Design of low noise 16bit cmos digitally controlled. Of all the lowfrequency oscillator configurations, the wien bridge is the easiest to use. Pdf digitally controlled oscillator dcobased architecture for.
User programming of the device is achieved via i2c or spi. A digitally controlled oscillator dco is an implementation of a variable frequency oscillator where the output frequency of the oscillator is controlled by one or more digital input signals. A digitally controlled oscillator dco based on capacitive degeneration in lctank is also implemented. A low jitter digitally controlled oscillator with differential outputs and good linearity is presented. The phase of the osc signal should be compared with a precise phase of the signal. The lowpower cmos dco is designed based on the ring oscillator implemented with schmitt trigger inverters. Digitally controlled oscillator dcobased architecture for rf frequency synthesis in a deepsubmicrometer cmos process robert bogdan staszewski, member, ieee, dirk leipold, khurram muhammad, and poras t. In this work it is studied and presented a new dco implementation technique with the purpose.
A low jitter digitally controlled oscillator semantic. A lowpower and lowjitter 12bit cmos digitally controlled oscillator dco design is presented. Digitally controlled oscillator with clock switching on 8. Abstractin this paper, a low power consumption 8bits. Overview of the numerically controlled oscillator nco the nco uses the direct digital synthesis dds technique to generate waveforms. All other components are fully digital and modular, allowing portability to any cmos process and customization for. In local oscillator applications, the vco frequency must be able to be varied over the rx or tx range quickly. Tb31 numerically controlled oscillator on pic mcus. Fine frequency resolution is achieved through highspeed spl sigmaspl delta dithering. Portability 2 an ultralowpower and portable digitally controlled oscillator for soc applications. Design of monotonic digitally controlled oscillator dco.
The 26 digitally controlled crystal oscillator dcxo combines the frequency stability of a crystal oscillator source with the flexibility of direct digital synthesis dds in a temperature controlled housing to provide a highly accurate output signal. Pdf a digitally controlled oscillator for finegrained. Analysis of a digitally controlled wienbridge oscillator. A 5 ghz 90 nm cmos all digital phaselocked loop, analog integrated circuits and signal processing 66 no. Design 16bit cmos digitally controlled oscillator ijert. Digitally controlled oscillator for mmwave frequencies rikard gannedahl, johan holmstedt department of electrical and information technology lund university supervisor. A novel digitally controlled oscillator dco based architecture for frequency synthesis in wireless rf applications is proposed and demonstrated.
A dividerby2 is an essential block to avoid local oscillator lo pulling 9. The proposed dco circuit uses control codes of thermometer type to reduce jitters. The oscillator module provides an easy and smooth process for switching operating frequencies. A novel digitallycontrolled oscillator dco is reported. Digitally controlled oscillator dcobased architecture.