A 3 Gbps Non-Contact Inter-Module Link with Twofold Transmission Line Couplers and Low Frequency Compensation Equalizer

Abstract

A non-contact inter-module link technique which consists of transmission line couplers (TLCs) and an equalizing receiver is proposed. The non-contact interface allows eliminating metal terminals and eases electro-static discharge (ESD) protection constraints, leading to higher channel bandwidth. Signals pass through two TLCs via a transmission line so that they are differentiated twice (d2v/dt2) and turn into double-peak pulses. To retrieve original waveforms, we developed a low-frequency compensation continuous time linear equalizer (LFC-CTLE) to emphasize the low frequency part converting the double-peak pulses to the first order differentiated shapes, resulting in improving the data rate. To verify this technique, we designed and fabricated a test chip in 0.18 µm CMOS technology and we achieved 3 Gbps data rate at the bit error rate of (BER) less than 10-11 with a 10-in. long FR4 micro strip line and two 11 mm length TLCs.