An Equalization Technique for Reducing Ringing in High-Speed CAN Bus Transceivers

The paper presents a new approach for ringing suppression in CAN (Controller Area Network) BUS, which makes use of an equalizer that is placed in front of the comparator of the CAN receiver. The proposed equalizer topology is made up of two RC branches in the form of two tee sections connected in parallel and a voltage resistive divider that is connected through two op-amps in feedback to the RC network. Five configurations of the equalizer can be selected to remove the ringing at different frequencies. The equalizer draws an average current of 400 mu A from a 5 V supply, while the entire receiver 1.5 mA. The chips were produced with 0.18 um high voltage BCD technology of TSMC. Two samples were characterized. All the results obtained are shown in this paper.