Design and modeling of high-Q variable width and spacing, planar and 3-D stacked spiral inductors
- 1 July 2014
- conference paper
- Published by Institute of Electrical and Electronics Engineers (IEEE)
- p. 1-6
Abstract
Layout optimized planar spiral inductors using variable width (W) and spacing (S) across their turns are known to exhibit higher quality factors (Q). In this paper, we explore the performance improvement of 3-dimensional, series-stacked, parallel-stacked, single ended, and symmetric inductor configurations with variable W&S across their turns. Parameterized cells for the aforementioned complex variable W&S inductor structures are developed in cadence using SKILL scripts for automatic generation of optimized inductor layouts with improved quality factors. The analyzed standard (constant W&S) and layout optimized (variable W&S) inductors are fabricated in a 0.18 μm silicon on insulator process. Measurement results show more than 20% improvement in quality factor for the 3-D stacked variable W&S inductor topologies. Furthermore, an accurate, scalable, and broadband compact inductor model was developed and is shown to capture the improved Q characteristics across the analyzed inductor topologies. A complementary LC-tank voltage controlled oscillator with layout optimized inductors, operating over 2.4-2.5 GHz frequency range was simulated using these developed compact models and is shown to exhibit an improved phase noise characteristics with better figure of merit.Keywords
This publication has 19 references indexed in Scilit:
- On‐chip spiral inductor with novel gradually changed structureMicrowave and Optical Technology Letters, 2008
- Frequency-independent equivalent-circuit model for on-chip spiral inductorsIEEE Journal of Solid-State Circuits, 2003
- Stacked inductors and transformers in CMOS technologyIEEE Journal of Solid-State Circuits, 2001
- Analysis of current crowding effects in multiturn spiral inductorsIEEE Transactions on Microwave Theory and Techniques, 2001
- Improvement of the quality factor of RF integrated inductors by layout optimizationIEEE Transactions on Microwave Theory and Techniques, 2000
- Simple accurate expressions for planar spiral inductancesIEEE Journal of Solid-State Circuits, 1999
- Improved quality factor spiral inductors on GaAs substratesIEEE Microwave and Guided Wave Letters, 1999
- Analysis, design, and optimization of spiral inductors and transformers for Si RF ICsIEEE Journal of Solid-State Circuits, 1998
- A 1.8-GHz low-phase-noise CMOS VCO using optimized hollow spiral inductorsIEEE Journal of Solid-State Circuits, 1997
- A three-step method for the de-embedding of high-frequency S-parameter measurementsIEEE Transactions on Electron Devices, 1991