3.2 multi-standard 185fsrms 0.3-to-28Gb/s 40dB backplane signal conditioner with adaptive pattern-match 36-Tap DFE and data-rate-adjustment PLL in 28nm CMOS
T. Kawamoto, T. Norimatsu, K. Kogo, F. Yuki, N. Nakajima, M. Tsuge, T. Usugi, Tomofumi Hokari, H. Koba, Takemasa Komori, Junya Nasu, Tsuneo Kawamata, Yuichi Ito, Seiichi Umai, J. Kumazawa, Hiroaki Kurahashi, T. Muto, T. Yamashita, M. Hasegawa, K. Higeta
{"title":"3.2 multi-standard 185fsrms 0.3-to-28Gb/s 40dB backplane signal conditioner with adaptive pattern-match 36-Tap DFE and data-rate-adjustment PLL in 28nm CMOS","authors":"T. Kawamoto, T. Norimatsu, K. Kogo, F. Yuki, N. Nakajima, M. Tsuge, T. Usugi, Tomofumi Hokari, H. Koba, Takemasa Komori, Junya Nasu, Tsuneo Kawamata, Yuichi Ito, Seiichi Umai, J. Kumazawa, Hiroaki Kurahashi, T. Muto, T. Yamashita, M. Hasegawa, K. Higeta","doi":"10.1109/ISSCC.2015.7062922","DOIUrl":null,"url":null,"abstract":"As processing and network speeds are accelerated to support data-rich services, the bandwidth of backplane interconnects needs to be increased while maintaining the channel length and multi-rate links. However, channel losses and impedance discontinuities increase at high data-rates, making it difficult to compensate the channel. In this work, we target serial links from auto-negotiation in 100G-KR4 of 0.3Gb/s to 32GFC of 28.05Gb/s in 40dB backplane architecture. To achieve this challenge, there are two key techniques. First, we introduce a 36-tap decision-feedback equalizer (DFE) to cancel reflections due to connectors because these reflections close the eye. To operate the 36-tap DFE, we need to fix a CDR lock-point and calculate 36-tap coefficients accurately. Thus, we develop a pattern-captured CDR with a 4b pattern filter to fix the lock-point, and a 3b pattern-matched adaptive equalizer (AEQ) to optimize 36 tap coefficients. These techniques enable our chip to compensate 40dB channel loss. Second, we target 100G-KR4/40G-KR4/10G-KR/25G-KR and 32GFC/16GFC/8GFC/4GFC. To operate across a wide range of data-rates, from 0.3 to 28.05Gb/s, with low jitter, we develop a PLL architecture with two LC-VCOs and one ring VCO with a data-rate-adjustment technique by controlling an LDO. Our test chip is fabricated in 28nm CMOS. Our signal conditioner is the demonstration to achieve the BER <;1012 PRBS31 at 100G-KR4 in a 40dB chip-to-chip backplane with two connectors by using the 36-tap DFE to cancel the reflection and to operate across a wide range of data-rates from 0.3 to 28.05Gb/s.","PeriodicalId":188403,"journal":{"name":"2015 IEEE International Solid-State Circuits Conference - (ISSCC) Digest of Technical Papers","volume":"49 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"2015-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"23","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"2015 IEEE International Solid-State Circuits Conference - (ISSCC) Digest of Technical Papers","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1109/ISSCC.2015.7062922","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 23
Abstract
As processing and network speeds are accelerated to support data-rich services, the bandwidth of backplane interconnects needs to be increased while maintaining the channel length and multi-rate links. However, channel losses and impedance discontinuities increase at high data-rates, making it difficult to compensate the channel. In this work, we target serial links from auto-negotiation in 100G-KR4 of 0.3Gb/s to 32GFC of 28.05Gb/s in 40dB backplane architecture. To achieve this challenge, there are two key techniques. First, we introduce a 36-tap decision-feedback equalizer (DFE) to cancel reflections due to connectors because these reflections close the eye. To operate the 36-tap DFE, we need to fix a CDR lock-point and calculate 36-tap coefficients accurately. Thus, we develop a pattern-captured CDR with a 4b pattern filter to fix the lock-point, and a 3b pattern-matched adaptive equalizer (AEQ) to optimize 36 tap coefficients. These techniques enable our chip to compensate 40dB channel loss. Second, we target 100G-KR4/40G-KR4/10G-KR/25G-KR and 32GFC/16GFC/8GFC/4GFC. To operate across a wide range of data-rates, from 0.3 to 28.05Gb/s, with low jitter, we develop a PLL architecture with two LC-VCOs and one ring VCO with a data-rate-adjustment technique by controlling an LDO. Our test chip is fabricated in 28nm CMOS. Our signal conditioner is the demonstration to achieve the BER <;1012 PRBS31 at 100G-KR4 in a 40dB chip-to-chip backplane with two connectors by using the 36-tap DFE to cancel the reflection and to operate across a wide range of data-rates from 0.3 to 28.05Gb/s.