Therefore, the charge pump will switch on and off, and current spikes will appear on the charge pump output at the reference frequency. A typical wide-tuning-range LC-VCO employs the use of a switched capacitor network for coarse tuning and a varactor for fine tuning, such as in [17,18]. The implemented design of the CML stage is shown in Figure 3. Therefore, it is expected that the circuit design and layout will have a detrimental influence on the resulting quality factor . The measured phase noise for Designs A and B are shown in Figure 5.
Cambridge University Press, Finally, this chapter discusses some future work that could improve the current work. Finally, the loop filter is the component most commonly used to control system-level loop dynamics . This section introduces the loop filter and discusses how we designed two loop filters, one for loop bandwidth 1 MHz and the other for loop bandwidth kHz. Both PMOS- and NMOS-only topologies can provide an output voltage swing greater than the voltage supply with the help of a high tail- 8 current feed-through.
The derivation of the closed loop transfer function is shown below: Electrical and Computer Engineering.
Low power low phase noise CMOS LC quadrature voltage-controlled oscillators
A typical wide-tuning-range LC-VCO employs the use of a switched capacitor network for coarse tuning and a varactor for fine tuning, such as in [17,18]. Another reason the CML stage is ideal for this design is because it is a high-speed logic circuit.
Methods of resolving them will be discussed in Section 7.
Both PMOS- and NMOS-only topologies can provide an output voltage swing greater than the voltage supply with the help of a high tail- 8 current feed-through. The design consists of one VCO core with a switched-capacitor which can be switched on or off, creating overlapping tuning tuesis. It was noted that the measured amplitude of Design A was smaller than that for Design B.
Their stabilized frequency and their differential peak-to-peak amplitudes at various stages are summarized in Table 4. Based on the control voltage, the VCO oscillates at a higher or lower frequency, which affects the phase and frequency of the quadratuee clock.
The first PLL was introduced in and today, decades later, there are still many people researching this circuit . The purpose of the inclusion of this section is so sufficient comparison can be made to the post-layout simulation results.
Several MOSFET oscillator architectures have been analyzed and the start-up times compared using this analysis with applications to start-up time reduction of LC oscillators. The aspect ratio of M1 and M2 was designed to guarantee that the VCO would work well, at the desired frequency. A symbolic TVRL analysis is capable of computing the system roots during an oscillation with the help of Muller algorithm.
The operation of the CML buffer is based on the differential pair circuit. The fourth state, where thwsis current sources are active, never occurs theoretically .
Holistic Design In High-Speed Optical Interconnects – CaltechTHESIS
Abstract Integrated circuit scaling has enabled a huge growth in processing capability, which necessitates a corresponding increase in inter-chip communication bandwidth.
One switched-capacitor is used here to have two modes, for a fair comparison with the two-core Design A. Sufficient adjustments are made based on simulation results. Measured results show A third state occurs when none of the signals is active.
Electrical engineeringTelecommunications engineering Keywords: The corresponding results are then analyzed to detect the failure mechanism which is responsible for relaxation oscillations. First, the design of the VCO core with the switched capacitor is described.
In the context of phase noise, one should pay special attention to the quality factor of the tank as any deterioration in the quality factor would adversely 69 affect the phase noise performance. When using a bias-T tbesis part of the equipment setup, the phase noise improved by approximately 2 dB. thezis
Holistic Design In High-Speed Optical Interconnects
However, if the transistor size is big, its parasitic capacitor is big as well when the switched-capacitor is off, so considering the trade-off we must debug carefully. In particular, wide tuning range, low phase noise, and low power are desirable attributes for multi-standard and multi-band communication systems. University of British Columbia Library.
Kenneth, “A fully integrated 5. The two designs were fabricated in a nm CMOS technology. This will be further discussed in Chapter 3. At very small offset frequencies the spectrum becomes flat again . Comparison of these results to simulation results is made, indicating that overall the results match approximately and show the same trend.
In what follows the first-order PLL is first discussed. De Muer and M.