Print Email Facebook Twitter Toward Solving Multichannel RF-SoC Integration Issues Through Digital Fractional Division Title Toward Solving Multichannel RF-SoC Integration Issues Through Digital Fractional Division Author Ahmadi Mehr, S.A.R. Tohidian, M. Staszeski, R.B. Faculty Electrical Engineering, Mathematics and Computer Science Department Microelectronics Date 2015-06-12 Abstract In modern RF system on chips (SoCs), the digital content consumes up to 85% of the IC chip area. The recent push to integrate multiple RF-SoC cores is met with heavy resistance by the remaining RF/analog circuitry, which creates numerous strong aggressors and weak victims leading to RF performance degradation. A key such mechanism is injection pulling through parasitic coupling between various LC-tank oscillators as well as between them and strong transmitter (TX) outputs. Any static or dynamic frequency proximity between aggressors (i.e., oscillators and TX outputs) and victims (i.e., oscillators) that share the same die causes injection pulling, which produces unwanted spurs and/or modulation distortion. In this paper, we propose and demonstrate a new frequency planning technique of a multicore TX where each LC-tank oscillator is separated from other aggressors beyond its pulling range. This is done by breaking the integer harmonic frequency relationship of victims/aggressors within and between the RF transmission channels using digital fractional divider based on a phase rotation. Each oscillator’s center frequency can be fractionally separated by ~28% but, at the same time, both producing closely spaced frequencies at the phase rotator outputs. The injection-pulling spurs are so far away that they are insignificantly small (?80 dBc) and coincide with the second harmonic of the carrier. This method is experimentally verified in a two-channel system in 65-nm digital CMOS, each channel comprising a high-swing class-C oscillator, frequency divider, and phase rotator. Subject digital fractional dividerdigitally controlled oscillator (DCO)frequency pullinginjection lockingmulti-core radioRF-SoCsystem on chip (SoC) To reference this document use: http://resolver.tudelft.nl/uuid:892a0f57-d8a8-405f-a75c-d619e9474a59 Publisher IEEE ISSN 1063-8210 Source https://doi.org/10.1109/TVLSI.2015.2436979 Source IEEE Transactions on Very Large Scale Integration (VLSI) Systems, 24 (3), 2015 Part of collection Institutional Repository Document type journal article Rights © 2015 IEEE Files PDF Ahmadi_Mehr_2015.pdf 3.67 MB Close viewer /islandora/object/uuid:892a0f57-d8a8-405f-a75c-d619e9474a59/datastream/OBJ/view