Electromagnetic interference suppression and simultaneous switching noise mitigation in system on package using a lowpass filter structure with embedded capacitor

Abstract

System on package (SOP) is an emerging technology, and provides an implementation options for system with small size, especially for mixed-signal systems. However, in such a compact package, noise generated by the digital chip can be easily coupled to the RF IC, and degrade the sensitivity of RF signal. In this paper, a simple and efficient multi-order lowpass filter for EMI and SSN suppression in system on package is implemented with embedded capacitor material. It has good performance in noise isolation with a small size of 10mm*mm. The lowpass filter is designed and simulated by electromagnetic analysis software, HFSS. The insertion loss is below -70dB from1.5GHz to 10GHz. Then, the lowpass filter is serial with a surface mounted 47nH inductor, and can achieve noise suppression below-50dB from 50MHz to 10GHz, below -60dB from 140MHz to 10GHz, and below80dB from 600MHz to 10GHz. That is very promising for system on package application in mixed-signal systems. The structure can also be used in large scale backplanes or motherboards. IntroductionConsumer electronics market demands for smaller size, lower cost, and higher level of integration have continued to drive the electronic systems to be convergent, and system on package (SOP) become an encouraging solution to improve circuit performance and reduce the system real estate [1]. SOP is more than an IC package containing multiple die, and seeks to integrate multiple system functions into one compact, lightweight, thin-profile, low cost, high performance packaged system [2]. The system design may include RF and wireless devices (such as power amplifiers, switch/filter modules, GPS modules, Bluetooth modules), digital baseband solutions and controllers. In such a compact SOP approach, digital IC are placed extremely close to RF IC to reduce the package size, and then electromagnetic interference (EMI) and simultaneous switching noise from the digital IC will certainly interfere with the RF operation [3]. How to suppress the noise propagation is becoming one of major challenges for SOP design.Prior to this work, power delivery network (PDN) with electromagnetic band gap (EBG) was considered to be a promising noise suppression technology [4][5][6][7]. To reduce the physical size and improve the performance of EBG structure, high dielectric constant embedded capacitor thin film material had also been employed [8][9][10]. But Most EBG structures had been developed for large scale backplane or motherboard applications [11][12][13][14][15]. Of course, some researchers had presented a few EBG solutions for packages. E. Song et al. had presented a spiral-patch EBG for < 5GHz SSN suppression in mixed-signal SIP [16]. J. Park had utilized a double-stacked EBG structure for 11.4 GHz noise stop bandwidth with -30dB suppression in SIP applications [17].But all of these EBG structures have severe disadvantages that limit their applications in productions. For example, the EBG structures are usually very complicated for fabrication, and the performances are sensitive to the siz...

A State-of-the-Art Review on Conducted Electromagnetic Interference in Non-Isolated DC to DC Converters

“…EMI is an undesirable disturbance that occurs due to switching and affects an electrical circuit [15]. EMI is categorized into radiated and conducted EMI.…”

“…Chenbin Tao et al [13] and Wu et al [14] introduced solution to reduce CM EMI in SMPS with hybrid filter (HEF). Li et al [15] used the system on package (SOP) Multi-order low pass filter for EMI and simultaneous switching noise suppression. It is concluded that the performance of noise isolation is achieved at a higher level with a smaller size.…”