An 80 mV-Swing Single-Ended Duobinary Transceiver With a TIA RX Termination for the Point-to-Point DRAM Interface Soo-Min Lee, Il-Min Yi, Hae-Kang Jung, Hyunbae Lee, Y ong-Ju Kim, Y un-Saing Kim, Byungsub Kim, Jae-Y

Abstract

A low-energy single-ended duobinary transceiver is proposed for the point-to-point DRAM interface with an energy efficiency of 0.56 pJ/bit at 7 Gb/s. The transmitter power is reduced by decreasing the signal swing of transmission channel to 80 mV and replacing the multiplexer and the binary output driver in the transmitter by a duobinary output driver. A trans-impedance amplifier (TIA) is used at the receiver end of transmission channel. The TIA works as a receiver termination and also ampli fies the input signal for subsequent processing. Analysis of the feedback loop delay and the nonlinearity of the TIA shows that they do not impose serious problems. The T IA output signal is applied to a duobinary-to-NRZ converter, which is implemented by using a direct feedback 1-tap DFE circuit with a tap-coef ficient of 1.0. The reference voltage of the duobinary-to-NRZ converter is calibra ted automatically to enable a small-swing signaling. The proposed transceiver chip in a 65 nm CMOS process works at 4.5 Gb/s with a3 ″ FR4 microstrip line, and at 7 Gb/s with a 0.6 ″ FR4.