Kyuwoon Hwang

A comprehensive compact-modeling methodology for spiral inductors in silicon-based RFICs

A new comprehensive wide-band compact-modeling methodology for on-chip spiral inductors is presented. The new modeling methodology creates an equivalent-circuit model consisting of frequency-independent circuit elements. A fast automated extraction procedure is developed for determining the circuit element values from two-port S-parameter measurement data. The methodology is extremely flexible in allowing for accurate modeling of general classes of spiral inductors on high- or low-resistivity substrate and for large spirals exhibiting distributed trends. The new modeling methodology is applied to general classes of spirals with various sizes and substrate parameters. The extracted models show excellent agreement with the measured data sets over the frequency range of 0.1-10 GHz.

A new wideband compact model for spiral inductors in RFICs

A new wide-band compact model for planar spiral inductors on lossy silicon substrate is presented. Transformer loops are used in the series branch of the equivalent circuit model to include the effects of the frequency-dependent losses, in particular eddy-current loss in the silicon substrate. The new compact model and the standard 9-element model are extracted from measurement data of a typical 1.5-nH spiral fabricated on a low-resistivity CMOS substrate over a frequency range of 0.1 to 10 GHz. The frequency-dependent series resistance and inductance as well as the quality factor obtained with the new model are in excellent agreement with the measured results.

A new compact model for monolithic transformers in silicon-based RFICs

A new compact model for monolithic transformers on silicon substrates is presented. The new lumped-element equivalent circuit model employs transformer loops to represent skin and proximity effects including eddy current loss in the windings of the transformer. In addition to the self-resistances and self-inductances of the windings, the effects of the frequency-dependent mutual resistance and mutual inductance are included in the model. The new compact model has been applied to a stacked transformer on a 10-/spl Omega//spl middot/cm CMOS substrate. The extracted circuit model shows very good agreement with data obtained by full-wave electromagnetic simulation and measurement over the frequency range of 0.1-10GHz.

Wide-band compact modeling of spiral inductors in RFICs

A new wide-band compact modeling methodology for planar spiral inductors on lossy silicon substrate is presented. The new ideal lumped-element equivalent circuit model employs transformer loops in the series branch to include the effects of the frequency-dependent losses, in particular eddy-current loss in the bulk silicon substrate. A robust automated extraction procedure is employed to extract the element values of the new compact model. The new automated modeling methodology has been applied to a typical 1.5 nH spiral fabricated on a low-resistivity CMOS substrate. The frequency-dependent series resistance and inductance as well as the quality factor obtained with the new wideband model are in excellent agreement with the measured results over a 10 GHz bandwidth.

Wide-band distributed modeling of spiral inductors in RFICs

A new wide-band model for planar spiral inductors on silicon substrate consisting of ideal lumped elements is presented. The equivalent circuit model captures the distributed behavior of the spiral for electrically large devices in particular with low self-resonant frequency. A fast, automated extraction procedure is developed for determining the circuit element values from two-port S-parameter data. The new modeling methodology is applied to extract a distributed model from the measured S-parameters of an electrically large 1.5-nH spiral. The extracted model shows excellent agreement with the measured data over a frequency range of 0.1 to 10 GHz.

Ultra-Compact Power Conversion Based on a CMOS-Compatible Microfabricated Power Inductor with Minimized Core Losses

A CMOS-compatible microfabricated inductor is presented. The inductor consists of a planar spiral coil optionally sandwiched between upper and lower magnetic core layers. Core materials investigated include ferrite-filled polymer and electrodeposited nickel-iron permalloy (Ni0.80Fe0.20).Four core constructions were investigated: air-core (i.e., no magnetic material); lower permalloy core with upper air core; lower permalloy core with upper ferrite polymer core; and lower and upper permalloy core. In all cases with magnetic cores, a nominal magnetic air gap of 2 microns was utilized. As expected, the all-permalloy construction yielded the highest inductance. Inductors were characterized both by impedance analysis as well as in a prototype buck DC-DC conversion circuit. When the converter was operated at 5 MHz, peak efficiency of 82% and an efficiency of 80% at a load current of 2.5 A and output voltage of 2 V was obtained.

Compact modeling of differential spiral inductors in Si-based RFICs

A new modeling methodology for on-chip differential spiral inductors is presented. The presented model consists entirely of frequency-independent circuit elements. An automated extraction technique is presented for determining the circuit elements from two two-port S-parameter measurement data sets. The new method allows for a single model to accurately capture the single-ended and differential operations of the device. The modeling methodology is applied to a sample differential spiral inductor. The extracted model shows excellent accuracy in comparison with device measurements over the frequency range 0.2 to 10.2 GHz.