On-Chip Bondwire Magnetics with Ferrite-Epoxy Glob Coating for Power Systems on Chip

Abstract

A novel concept of on-chip bondwire inductors and transformers with ferrite epoxy glob coating is proposed to offer a cost effective approach realizing power systems on chip (SOC). We have investigated the concept both experimentally and with finite element modeling. A <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>Q</mml:mi></mml:math> factor of 30–40 is experimentally demonstrated for the bondwire inductors which represents an improvement by a factor of 3–30 over the state-of-the-art MEMS micromachined inductors. Transformer parameters including self- and mutual inductance and coupling factors are extracted from both modeled and measured <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>S</mml:mi></mml:math>-parameters. More importantly, the bondwire magnetic components can be easily integrated into SOC manufacturing processes with minimal changes and open enormous possibilities for realizing cost-effective, high-current, high-efficiency power SOCs.