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Seamless package-level integration of multiple dies for high-performance computing and networking requires broadband dense die-to-die interconnect. Organic packaging substrates offer lower cost and lower loss interconnect, whereas silicon interposers offer higher density interconnect. In this work, a silicon interposer is fabricated in a relatively inexpensive 0.35 μm CMOS technology as an alternative...
In this work we report on the performance of a MISFET device realized by exploiting the peculiarities of Vanadium Pentoxide (V2O5) as insulating material between the gate metal and the hydrogenated single crystal diamond surface. As opposed to the typical oxide materials (such as Al2O3), the high electron affinity of the proposed oxide allows for the p-type charge transfer doping of the underlying...
We report the first generation of GaN MMIC circuits that are based on the latest generation of (ft > 320 GHz and fmax > 580 GHz) [1] GaN Transistors. The reported broadband Ka-band (27 GHz - 40 GHz) GaN LNA MMIC's have Noise Figure (NF) as low as 1 dB measured at a frequency of 37 GHz, NF < 2 dB with >24dB of gain across 28 GHz- 39.2 GHz frequency range, and a very broad range of usable...
Clock and Data Recovery (CDR) circuits perform the function of recovering clock and re-timing received data in optical links. These CDRs must be capable of tolerating large input jitter (high JTOL), filter input jitter (low JTRAN with no jitter peaking) and in burst-mode applications be capable of phase locking in a very short time. In this paper, we elucidate these design tradeoffs and present various...
This paper presents a highly integrated, high performance four channel linear transimpedance amplifier (TIA) RFIC with a footprint of 2mmx3.5mm towards next generation 100G/400G miniaturized coherent receivers. A TIA of such form may become indispensable as the size, complexity and cost of receivers continue to reduce. The design has been realized in a 130nm SiGe BiCMOS process for a low cost, high...
This paper describes the design and measured performance of two high efficiency Ka-band 32 - 38 GHz power amplifier MMICs fabricated with an advanced 0.15μm Gallium Nitride (GaN) HEMT technology process. The process features a 50μm thin Silicon Carbide (SiC) substrate and compact transistor layouts with individual source via (ISV) grounding. The designs utilize an optimum transistor arrangement with...
For the first step of evaluation of the effect of difference frequency distortion in intermodulation distortion and memory effects, we have derived distortion characteristics at the difference frequency as well as third-order intermodulation. In practical calculation of Volterra kernel in frequency domain, we used measured I-V characteristics, and S-parameters in both fundamental (around 2 GHz) and...
A dual-mode NRZ/PAM4 SerDes seamlessly supports both modulations with a 1-FIR- and 2-IIR-tap DFE receiver and a 4/2-tap FFE transmitter in NRZ/PAM4 modes, respectively. A source-series-terminated (SST) transmitter employs lookup-table (LUT) control of a 31-segment output DAC to implement FFE equalization in NRZ and PAM4 modes with 1.2Vpp output swing and utilizes low-overhead analog impedance control...
We report on an 850nm VCSEL based link operating error free to 71 Gb/s using an NRZ modulation format. This optical link uses custom transmitter and receiver ICs with 2-tap Feed Forward Equalization implemented in 130nm BiCMOS and GaAs based VCSELs and photodiodes. This paper covers new aspects of the circuits and packaging.
Millimeter wave (mmWave) is coming to fifth generation (5G) cellular, wireless local area networks (WLANs), and wireless personal area networks (WPANs). The benefits of using millimeter wave carriers arise from the potential for larger bandwidths (hundreds of megahertz to gigahertz) compared to lower carrier frequencies. Differences in the propagation, challenges introduced by hardware constraints,...
Strategies aimed at improving the near junction heat removal of Gallium Nitride (GaN) High Electron Mobility Transistors (HEMTs) are presently limiting GaN device technology from realization of its true capability [1]. Approximately ten years ago, Cree demonstrated AlGaN/GaN HEMTs with power densities exceeding 40 W/mm [2]. Control of the GaN junction temperature requires integration of thermal transport...
We report MMIC traveling-wave amplifiers (TWAs) fabricated using a 40 nm GaN double heterostructure FET (DHFET) technology. By varying the gate periphery within cascode gain stages, we produced a family of TWA designs with a range of gain and bandwidth and approximately 300 GHz gain- bandwidth product. The TWA with the widest bandwidth had >120 GHz of 3-dB bandwidth, with 7.3 dB gain, 6 dB noise...
This paper reports on a novel 0.1-44 GHz linear common-drain-Cascode (CD-Cascode) GaN distributed amplifier architecture with improved IP3-BW performance. The CD-Cascode DA MMIC is based on a 0.15μm GaN-HEMT wafer process technology. By exploiting the common-drain-Cascode as a transconductance device cell, an improvement in IP3 of 9 dB at mid-band (20GHz) and > 3 dB from 30-44 GHz were achieved...
A stacked-FET power amplifier (PA) with harmonic- tuned output matching network is demonstrated using a 0.15-µm Gallium Arsenide (GaAs) technology. The fabricated PA exhibits 28.5 dBm output power, 12 dB gain and 38.4% power added efficiency (PAE). To the best of our knowledge, this is for the first time stacked-FET technique is used in combining with harmonic-tuned output network to achieve high...
The transmission capacity of Ethernet has grown rapidly. Advanced multilevel modulation schemes, such as a 4-level pulse amplitude modulation (PAM4), are being investigated as to their suitability for next-generation 400GbE. The demand is now high for a transmitter front-end with a low-power laser diode (LD) driver that is applicable to such multilevel modulations. To meet this demand, we devised...
This paper investigates a novel AlGaN/GaN HEMT-based high power amplifier for continuous wave operation in industrial power applications. A GaN HEMT device with a power density of 50 W/mm² was developed to counter specific challenges in these applications. Based on RF load-pull measurements of the developed transistors an inverse class-F power amplifier with an output power of 300 W and an efficiency...
This paper reviews recent work aimed at a comprehensive assessment of the potential of SiGe technology to support emerging millimeter-wave (mm-wave) and sub-mm-wave integrated circuit applications. Scaling limits, reliability constraints, and the limits of CMOS for mm-wave are addressed, followed by a diverse variety of mm-wave and sub-mm-wave SiGe circuits that are offered as examples of the many...
We describe packaging challenges for the development of practical THz imagers based on InP transistor circuits. Very high aspect ratio (>20:1) die singulation and additive manufacturing for waveguide housings are shown to help in addressing these challenges.
The purpose of our work was to carry out a direct measurement of a GaN's surface condition under a voltage stress, and to identify a cause of a current collapse. Using pulsed S-parameters measurements immediately after the voltage stress was applied for the GaN HEMT, equivalent circuit parameters were extracted, and we estimated the virtual gate length which induced the current collapse. And we carried...
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