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Delay locked loop is a critical building block of high speed synchronous circuits. An improved architecture of amixed signaldelay locked loop (DLL) is presented here. In this DLL, delay cell based on single ended differential pair configuration is used for voltage controlled delay line (VCDL) implementation. This delay cell provides a high locking range with less phase noise and jitter due to differential pair configuration.For increasing the acquisition range and locking speed of the DLL, modified true single phase clock (TSPC) based phase frequency detector is used. [5]. Locking time, lock range and jitter performance, static phase error, low power consumption and immunity against process voltage temperature loading (PVTL) variations are the most important metrics of a DLL. A DLL can be realized by a number of architectures; analog and digital DLLs are the two most important types among them [6]. Analog DLLs have better performance in terms of jitter, layout area, power supply rejection ratio, power consumption and clock skew. This paper introduces a mixed mode DLL in which single ended differential pair based VCDL is used which provides high stability against temperature and power supply variations. The proposed circuit depicts superior performance in terms of speed, power consumption, and locking range. The organization of remaning four sections are starting with architecture of basic DLL followed by analysis of different blocks, simulation results and conclusion.

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This article mainly emphases on the performance study and characterization of CMOS voltage control ring oscillator (VCRO). The performance analysis is based on high frequency, low area, and low phase noise for different kind of techniques of VCRO at various supply voltages. The results shows higher frequency and less phase noise which can be suitable for different domain applications. Further advantage is as go on reducing the supply voltage the frequency of the VCRO is increasing rapidly. This paper helps the designers in order to choose the most suitable voltage control ring oscillator (VCRO) for their specific applications.

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