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Item type:Publication, Access status: without files , Bayesian optimization of first-order continuous-time linear equalization in high-speed links including crosstalkIn this work, the Bayesian optimization algorithm is utilized to find optimal coefficients for a first-order Continuous-Time Linear Equalizer (CTLE). The goal function for the optimization is derived from the single-bit response in the time domain. The performance of the optimized CTLE is compared to a frequency domain-based method for predicting the CTLE coefficients and a grid search over all possible combinations. The analysis is presented for two different PCB-based high-speed channels and with a 32 Gbps data rate. As a novel contribution, far-end crosstalk is included in the optimization. The resulting noisy behavior of the single-bit response is learned during the optimization as part of the Gaussian process model.Publicationtype: Conference Paper46 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Hardware Verification of Via Crosstalk Cancellation for Differential BGA-to-BGA LinksCoupling in dense via pinfields is known as a major contributor to crosstalk. In this work we present and verify a novel wiring strategy for links with a symmetrical pinfield-to-pinfield topology that reduces crosstalk significantly and requires no extra shielding vias. By twisting the orientation of the p and n wires of the differential stripline pair, a cancellation of the crosstalk between the differential via pairs is achieved. It can be implemented without any additional space requirements. The proposed design is fabricated and the crosstalk is measured with a vector network analyzer. It is shown that small changes in the orientation of the wiring in the pinfield region can reduce far-end crosstalk significantly.Publicationtype: Conference Paper34 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , 59 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , ANN performance for the prediction of high-speed digital interconnects over multiple PCBsIn this paper the performance and the accuracy of artificial neural networks for the prediction of high-speed digital interconnects up to 100 GHz on printed circuit boards are analyzed and evaluated. The prediction accuracy is evaluated both for scattering parameters in frequency domain as well as weighted power sums thereof. The interconnects considered all contain a backplane connected to a daughtercard, showing two via arrays each. Several parameter variations of the basic setup lead to a wide range of possible transmission and crosstalk parameters. Training data sets are obtained using physics-based via modeling up to 100 GHz. Approximately 7000 data sets were made available in total for this study. Neural networks are able to predict the overall link behavior.Publicationtype: Conference Paper111 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Bayesian Optimization for Signal Transmission including Crosstalk in a Via Array(2020-09-23); ; ; ; Signal integrity is becoming an important aspect of EMC engineering of digital systems. The signal integrity performance of printed circuit board links is influenced by a large number of design choices. Bayesian Optimization is a method that can optimize a large number of parameters in a reasonable amount of time. In this work it is shown that Bayesian Optimization can be used for the optimization of interconnect models with respect to their transmission and crosstalk performance. The first example is the optimization of the transmission of a single via. The second example is a 10 by 10 via array where the optimization includes transmission and crosstalk. The results obtained with the Bayesian Optimization are compared with the results of a Genetic Algorithm and with design guidelines derived from a physical perspective.Publicationtype: Conference Paper74 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Efficient Crosstalk Analysis of Differential Links on Printed Circuit Boards Up to 100 GHzWith bitrates increasing beyond 50 Gb/s, new challenges arise for the electrical modeling and evaluation of printed circuit boards (PCBs). In this work, an efficient modeling technique for the analysis of differential far-end crosstalk in a typical PCB link up to 100 GHz is proposed. The crosstalk of an interconnect is analyzed by separating the link into different subcomponents that include two via arrays and the striplines connecting them. By validating with full-wave simulations, it is shown for this frequency range that the physics-based via modeling approach in conjunction with a quasistatic two-dimensional transmission line model is an accurate and fast modeling approach, thus enabling a quick design analysis of PCB links. Based on a simultaneous variation of all the relevant geometrical parameters, with a total of about 59 000 model variations, the dependencies of differential far-end crosstalk on the link geometry are explored. Among other conclusions, it is found that the large variance in crosstalk is not dominated exclusively by a single parameter.Publicationtype: Journal Article147 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Evaluation of Neural Networks to Predict Target Impedance Violations of Power Delivery Networks(2019-10-06); ; Publicationtype: Research Report192 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Performance Metrics for Crosstalk on Printed Circuit Boards in Frequency DomainCrosstalk is an important factor that determines the performance of a digital link on printed circuit boards. An evaluation of the overall performance in frequency domain could eliminate the need for elaborate time domain simulations. The weighted power sum of crosstalk and the weighted power sum of transmission are introduced as simple figures of merit that allow a comparison of transmission and crosstalk in frequency domain. It will be shown that these figures of merit can be used for the evaluation of the impact of parameter variations of a typical printed circuit board link. The equivalence with the integrated crosstalk noise is studied. Both metrics are compared with eye diagrams.Publicationtype: Conference Paper163 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Via Transition Optimization Using a Domain Decomposition ApproachA method to minimize the return loss for via interconnects on printed circuit boards (PCB), based on the domain decomposition of traces, via barrels, and trace-to-via transitions is presented. This decomposition allows to optimize different via lengths, by separating the via barrel as an independent domain. The method is demonstrated by full-wave simulations. It starts by optimizing the via impedance, matching the traces by an appropriate size of the via environment followed by a subsequent compensation of trace-to-via transition discontinuities. Equivalent circuits of each domain are used to corroborate the performance improvement. Three pad geometries are proposed to compensate the discontinuities of a trace-to-via transition. For a long via on a PCB with eleven metal layers, using four ground vias, it was possible to achieve a wide-band low-reflection response below -30 dB from DC up to 32 GHz for microstrip traces and -37 dB from DC up to 20 GHz for stripline traces.Publicationtype: Conference Paper138 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Mode Conversion Due to Residual Via Stubs in Differential SignalingMode conversion is an important source of degradation in differential links, which can be induced by a trace length mismatch or asymmetric ground via configurations. This paper explores another source of mode conversion caused by asymmetric residual via stubs. These remnant via stubs can be present because of multiple reasons, such as residual stubs due to process tolerances or errors during back-drilling. Different via configurations have been analyzed through full-wave simulations. Results show a large impact on mode conversion with an increment of around -35 and -15 dB when the residual stub difference changes from 2 to 14 mil at the fundamental frequency of 17.5 GHz. Furthermore, an estimation approach of mode conversion as a function of via stub asymmetry is proposed.Publicationtype: Conference Paper641