In this article, the design and characterization of package-embedded solenoid inductors for a high-efficiency, four-phase system-in-package (SIP) buck-type integrated voltage regulator (IVR) switching at 100 MHz is discussed. The IVR enables three conversion ratios (5, 3, and 1.7–1 V) with a minimum inductance of 25 nH/phase and a load current of 10 A (2.5 A/phase). Two inductor designs (one with a rectangular core made of an epoxy dielectric/NiZn ferrite composite magnetic material/epoxy dielectric stack and one with an elliptical core of NiZn ferrite composite magnetic material only) were optimized and compared based on the highest achievable IVR efficiency. At high-load conditions (>5 A), the elliptical core inductor showed higher efficiency than the rectangular core inductor over the frequency range investigated (10–100 MHz). The elliptical core inductors were fabricated using a novel fabrication process combining core printing, noncontact photolithography, and copper electroplating. Two simple deembedding techniques which use a single thru structure and its equivalent circuit model as well as a cascade-based two-port analysis were introduced for the characterizations of the fabricated inductors. The accuracy of these deemebedding techniques was assessed using commercial, fixed-air core inductors and standard THRU and thru–reflect–line (TRL) deembedding for comparison purpose. Less than 5% difference was observed between the TRL and the introduced deembedding techniques for the inductance and ac resistance for both the fixed air core and package-embedded magnetic core inductors. The extracted electrical parameters of the fabricated inductors were compared with the modeling results and a good correlation was observed at 100 MHz.

中文翻译：

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高频，高效SIP集成稳压器的嵌入式电磁线圈电感的设计与表征

在本文中，讨论了用于100MHz高效开关的四相系统级封装（SIP）降压型集成稳压器（IVR）的封装嵌入式螺线管电感器的设计和特性。IVR支持三种转换比（5、3和1.7-1 V），最小电感为25 nH /相，负载电流为10 A（2.5 A /相）。基于可获得的最高IVR效率，对两种电感器设计（一种具有由环氧电介质/ NiZn铁氧体复合磁性材料/环氧树脂电介质叠层制成的矩形芯，以及一种仅具有NiZn铁氧体复合磁材料的椭圆形芯）进行了优化和比较。在高负载条件下（> 5 A），在研究的频率范围（10-100 MHz）中，椭圆形铁芯电感器的效率高于矩形铁芯电感器。椭圆形铁芯电感器是使用结合铁芯印刷，非接触光刻和电镀铜的新颖制造工艺制造的。引入了两种简单的去嵌入技术，这些技术使用单个直通结构及其等效电路模型以及基于级联的两端口分析来表征所制造的电感器。为比较起见，使用商用的固定空芯电感器和标准的THRU和直通反射线（TRL）去嵌入技术评估了这些去磁技术的准确性。对于固定空芯和封装嵌入式磁芯电感器，TRL与引入的去嵌入技术的电感和交流电阻之间的差异小于5％。