Chih-Pin Hung

Modeling of lead-frame plastic CSPs for accurate prediction of their low-pass filter effects on RFICs

This paper presents a direct extraction method to construct the electrical models of lead-frame plastic chip scale packages for RF integrated circuits (RFICs) from the measured S-parameters. To evaluate the package effects on the reciprocal passive components, the insertion and return losses for an on-chip 50-/spl Omega/ microstrip line housed in a 32-pin bump chip carrier (BCC) package were analyzed based on the established package model. Excellent agreement with measurement has been found up to 15 GHz. When applied to the nonreciprocal active components, the gain variations for a heterojunction-bipolar-transistor array housed in an 8-pin BCC package have also been successfully predicted up to 22 GHz. Both cases have demonstrated that the package acts as a low-pass filter to cause a sharp cutoff for the RFIC components above a certain frequency.

Electrical performance improvements on RFICs using bump chip carrier packages as compared to standard thin shrink small outline packages

The electrical models of bump chip carrier (BCC) packages have been established based on the S-parameter measurement. When compared to the standard thin shrink small outline packages (TSSOPs), BCC packages show much smaller parasitics in the equivalent model. In the simulation, the insertion and return losses for a packaged 50-/spl Omega/ microstrip line are calculated against frequency. BCC packages are also less lossy than TSSOPs over a wide frequency range. By setting a random variable with Gaussian distribution varied within a certain range for each equivalent circuit element of the packages, the Monte Carlo analysis has been performed to study the package effects on a GaAs heterojunction bipolar transistor (HBT). Again, BCC packages cause less decrement of HBT unity-gain bandwidth than TSSOPs.

Electrical performance improvements on RFICs using bump chip carrier packages as compared to standard small outline packages

The electrical models of Bump Chip Carrier (BCC) packages have been established based on the S-parameter measurement. When compared to the standard Thin Shrink Small Outline Packages (TSSOP), BCCs exhibit much smaller parasitics in the equivalent circuits. In the simulation, the insertion and return losses for an arbitrary pair of package leads connected through an on-die 50-ohm line are calculated against frequency. BCCs also show better loss characteristics than TSSOPs over a wide frequency range. By setting a random variable with Gaussian distribution varied within a certain range for each equivalent circuit element of the packages, the Monte Carlo analysis has been performed to study the package effects on a GaAs Heterojunction Bipolar Transistor (HBT). Again, BCCs cause less decrement of HBTs unity-gain bandwidth than TSSOPs.

Optimum Design of Transformer-Type Marchand Balun Using Scalable Integrated Passive Device Technology

A simple and effective technique for designing transformer-type Marchand baluns is presented in this paper. The coupled-line sections required in a Marchand balun design are realized using planar transformers with a scalable model. The proposed design technique enables the prediction and optimization of Marchand balun performance over a wide range of layout and process parameters. To demonstrate the optimization process, Marchand baluns are designed for implementation using silicon and glass integrated passive device (IPD) technologies. Finally, experimental verification shows very good agreement between the modeled and measured results, thereby validating the IPD design optimization.

Vertical interconnect measurement techniques based on double-sided probing system and short-open-load-reciprocal calibration

This work develops a double-sided probing system and calibration method for measuring the S-parameters of vertical interconnects at the wafer, package and socket level. The applicable device under test (DUTs) include through silicon vias (TSVs), plated through holes (PTHs), pogo pins and pressure sensitive conductive rubbers (PCRs). The effects of solder bumps and balls can also be taken into account. A short-open-load-reciprocal (SOLR) calibration method is used with a reciprocal thru to instead of the conventional short-open-load-thru (SOLT) which uses a standard thru. The S-parameters can be measured up to 40 GHz with a repeatable S21 parameter accuracy of better than 0.2 dB and 1 degree in magnitude and phase, respectively. Additionally, the eye diagrams are measured at a maximum data rate of 40 Gb/s and a minimum rise time of 10 ps with the help of Agilent physical layer test system (PLTS).

Super broadband lumped models for embedded passives

This paper presents novel equivalent lumped circuits to model three-dimensional inductors and capacitors embedded in a multilayer organic or LTCC substrate with extremely large bandwidth. The developed models combine a core circuit, a five-element modified-T section, to include up to half-wavelength long transmission-line effects, and parallel and series feedback resonators to account for non-conductive and common-ground coupling phenomena. It is emphasized that all the circuit elements in such equivalent models can be extracted mathematically from the measured S parameters. In our establishment of an embedded passives library, the modeled S parameters can agree quite well with measured results over the entire measurement frequency range of 20 GHz. The effective modeling bandwidth is estimated at least several times larger than in the conventional PI-section models.

Development of high-Q embedded passive library for RF-SOP module applications

Scalable broadband modeling techniques have been developed for the high-Q passive components buried into the organic laminate package substrate. Based on modified-T equivalent circuits, the developed models can achieve an effective bandwidth several times larger than the conventional PI models. For scalability, the fundamental reactive elements in a modified-T model can be converted directly from those in an existing scalable PI model. Curve-fitting techniques are particularly applied for the peak Q factors and the resonant frequencies that can be further converted into the resistive elements and the higher-order reactive elements, respectively, to form a complete modified-T model. In this paper, the proposed scalable modeling techniques have accomplished the automatic generation of broadband lumped models for designing the embedded passives in a 4-layer BT (Bismaleimide Triazine) laminate, one of todays most popular package substrate, quite successfully.

Design and modeling of planar transformer-based integrated passive devices for wireless applications

This paper presents design and modeling techniques of integrated passive devices (IPDs) that can be stacked with RF chips in a highly integrated and miniaturized 3D system-in-package (SiP) for wireless applications. The research starts to study winding and modeling techniques for high efficiency planar transformers. Based upon the proposed and modeled planar transformers, the research explores novel planar transformer-based structures for various kinds of wireless passive components including baluns, bandpass filters and power combiners to achieve miniature size as well as high performance. The IPDs presented in this study are manufactured in an Above-IC (AIC) process that is ready for mass production in semiconductor industry.

Very Compact Stacked LC Resonator-Based Bandpass Filters With a Novel Approach to Tune the Transmission Zeros

This letter presents very compact stacked LC resonator structures and their coupling and excitation techniques for designing the bandpass filters operating in the 3.5 GHz WiMAX band. Using a coupled stacked LC-resonator structure not only greatly reduces the overall size but also can create multiple transmission zeros to enhance roll-off rate or desired stopband rejection for the designed bandpass filters. Furthermore, this letter develops a simple technique of etching a rectangular C-shaped slot in the bottom ground plane to flexibly adjust the transmission-zero frequencies without changing the size and shape of the filter.

Design of super-miniature bandpass filters embedded in the organic substrate without using large-value capacitors

Very small-size bandpass filters embedded in the organic substrate for wireless front-end applications are presented. Due to the lack of fabrication process for large-value capacitors in the organic substrate, a filter prototype using an inductive coupling of series resonators is proposed to achieve high performance within a stringent size constraint. In implementation, the organic bandpass filters are composed of the spiral inductors and parallel-plate capacitors that are embedded in a 4-layer BT laminate, one of todays most popular package substrate. The final realized performance and size are competitive to the LTCC filters but with a much lower cost