CMOS Power Amplifier Design Techniques for UWB Communication: A Review

This paper reviews CMOS power amplifier (PA) design techniques in favour of ultra-wideband (UWB) application. The PA circuit design is amongst the most difficult delegation in developing the UWB transmitter due to conditions that must be achieved, including high gain, good input and output matching, efficiency, linearity, low group delay and low power consumption. In order to meet these requirements, many researchers came up with different techniques. Among the techniques used are distributed amplifiers, resistive shunt feedback, RLC matching, shuntshunt feedback, inductive source degeneration, current reuse, shunt peaking, and stagger tuning. Therefore, problems and limitation of UWB CMOS PA and circuit topology are reviewed. A number of works on the UWB CMOS PA from the year 2004 to 2016 are reviewed in this paper. In recent developments, UWB CMOS PA are analysed, hence imparting a comparison of performance criteria based on several different topologies

Wideband integrated circuits for optical communication systems

The exponential growth of internet traffic drives datacenters to constantly improvetheir capacity. Several research and industrial organizations are aiming towardsTbps Ethernet and beyond, which brings new challenges to the field of high-speedbroadband electronic circuit design. With datacenters rapidly becoming significantenergy consumers on the global scale, the energy efficiency of the optical interconnecttransceivers takes a primary role in the development of novel systems. Furthermore,wideband optical links are finding application inside very high throughput satellite(V/HTS) payloads used in the ever-expanding cloud of telecommunication satellites,enabled by the maturity of the existing fiber based optical links and the hightechnology readiness level of radiation hardened integrated circuit processes. Thereare several additional challenges unique in the design of a wideband optical system.The overall system noise must be optimized for the specific application, modulationscheme, PD and laser characteristics. Most state-of-the-art wideband circuits are builton high-end semiconductor SiGe and InP technologies. However, each technologydemands specific design decisions to be made in order to get low noise, high energyefficiency and adequate bandwidth. In order to overcome the frequency limitationsof the optoelectronic components, bandwidth enhancement and channel equalizationtechniques are used. In this work various blocks of optical communication systems aredesigned attempting to tackle some of the aforementioned challenges. Two TIA front-end topologies with 133 GHz bandwidth, a CB and a CE with shunt-shunt feedback,are designed and measured, utilizing a state-of-the-art 130 nm InP DHBT technology.A modular equalizer block built in 130 nm SiGe HBT technology is presented. Threeultra-wideband traveling wave amplifiers, a 4-cell, a single cell and a matrix single-stage, are designed in a 250 nm InP DHBT process to test the limits of distributedamplification. A differential VCSEL driver circuit is designed and integrated in a4x 28 Gbps transceiver system for intra-satellite optical communications based in arad-hard 130nm SiGe process

Design and Simulation of Two Stage Wideband CMOS Amplifier in 90 NM Technology

Design and simulation of 7 GHz CMOS wideband amplifier(CMOSWA) using a modified cascode circuit realized in  90-nm CMOS technology is presented here. The proposed system consists of two stages, namely a modified folded cascode and an inductively degenerated common source amplifier. The circuit is experimented with and without a feedback network. This work discusses the performance variation as a function of reactive components, and the initial stage results in 22 dB gain,2.6 GHz bandwidth, and 40GHz unity gain-bandwidth. The circuit without the feedback network exhibits 30.7dB gain,4.8GHz bandwidth(BW), and 10GHz unity-gain bandwidth(UGB). The reactive feedback network's inclusion helped to achieve 38.7 dB gain, 6.95GHz BW, 30GHz UGB, and 55o phase margin. The circuit consumes 1.4mW power from a 1.8V power supply. Simulation results of the proposed circuit are comparable and better than the reported wideband designs in the literature. Realization of our proposed circuit would add value to the area of wideband amplifier design

High Efficiency, Good phase linearity 0.18 µm CMOS Power Amplifier for MBAN-UWB Applications

This paper presents the design of 3.1-10.6 GHz class AB power amplifier (PA) suitable for medical body area network (MBAN) Ultra-Wide Band (UWB) applications in TSMC 0.18 µm technology. An optimization technique to simultaneously maximize power added efficiency(PAE) and minimize group delay variation is employed. Source and Load-pull contours are used to design inter and output stage matching circuits. The post-layout simulation results indicated that the designed PA has a maximum PAE of 32 % and an output 1-dB compression of 11 dBm at 4 GHz. In addition, a small group delay variation of ± 50 ps was realized over the whole required frequency band . Moreover, the proposed PA has small signal power gain (S21) of 12.5 dB with ripple less than 1.5 dB over the frequency range between 3.1 GHz to 10.6 GHz, while consuming 36 mW

Analysis and Design of Wideband CMOS Transimpedance Amplifiers Using Inductive Feedback

Optical receivers have an important role in high data rate wireline data communication systems. Nowadays, these receivers have data rates of multi Gb/s. To achieve such high data rate in the design of optical receivers, all the amplifiers in the signal path need to be wideband and at the same time have minimum gain variations in the passband. As a rule of thumb, the bandwidth of amplifiers in the optical receivers should be 70% of the data rate. The first component of the optical receiver is photodiode which converts photons received from optical fiber to current signals. The small current received from the photodiode is amplified using the transimpedance amplifier (TIA) which is one of the main building blocks in the receiver frontend. Due to high data rate of fiber optic communication systems the bandwidth of TIAs should be high and it should satisfy gain requirements. It has been shown that inductive feedback technique is capable of extending the bandwidth of CMOS TIAs amplifiers effectively. However, no mathematical analysis is available in the literature explaining this phenomenon. The main focus of this thesis is to explain mathematically the mechanism of bandwidth extension of CMOS TIAs with inductive feedback. In this thesis, it is shown mathematically that the bandwidth extension of inverter based CMOS TIAs with inductive feedback is due to either zero-pole cancellation or change in the characteristics of complex conjugate poles. It is shown that for large photodiode capacitance for example 150fF the phenomenon for the bandwidth extension is zero pole cancellation. In the case of small photodiode capacitance for example 50fF, the bandwidth extension happens due to change in the characteristics of complex conjugate poles. Finally, the zero pole cancellation using inductive feedback method for common source based transimpednace amplifier with resistive load using different values of photodiode capacitances has been analyzed. In addition to that a new 3-stage common source based transimpedance amplifier using inductive feedback technique is designed. The process of bandwidth extension is shown analytically and is confirmed with simulation results using well-known tools and technologies. To show the system level motivation, an eye diagram simulation is performed for all topologies and it is verified that bandwidth extension does not disturb the performance. Moreover, the concept is verified based on a frequency scaled down discrete implementation. In this thesis, for inverter based CMOS TIA using photodiode capacitances of 150fF and 50fF bandwidths of 16.7GHz and 29.7GHz are achieved. In the case of common source based TIAs, considering 50fF, 100fF, 150fF photodiode capacitances, -3dB bandwidths of 32.1GHz, 21.8GHz, and 15.8GHz are achieved. A new three-stage TIA is proposed which achieves bandwidths of 42.8GHz, 35.5GHz, and 28.5GHz for 50fF, 100fF, 150fF photodiode capacitances. Based on comparative analysis, it is shown that, inductive feedback is the most effective method to extend the bandwidth of TIAs in terms of number of inductors