A mathematical formulation to design and implementation of a low voltage swing transceiver circuit

On switching a transmitter at gigahertz rate, the data at the receiver's end gets distorted in terms of pulse width and voltage due to line loss and dispersion originating from channel electrical characteristics. Signalling using current sources is an established approach for high frequency applications, but different receiver circuits have been proposed to effectively sense the low voltage swings around some reference voltage, VT. At first, the VT is identified at the receiver's input by a unique method and the corresponding value is found to be 0.822 V. Thereafter, a signalling scheme has been proposed to have two different current sources capable of generating a low voltage swing around VT at the receiver's end and at the same time compensating the line loss of the channel. The low voltage swings around VT cause leakage current to increase. The proposed methodology reduces the constant short circuit current due to low voltage swings around VT almost close to 0 from 56 μA for 60 mV swing. The PVT analyses of the VT determination circuit and the proposed signalling scheme indicate the sensitivity of the proposed approach while operated at 1 GHz switching frequency. Further, the crosstalk analysis for a 60 mV swing around VT at 180 nm CMOS process and single ended point to point drivers portrays that the desired s/h (s is the edge to edge space between two traces and h is the corresponding height from the ground plane) has to be greater than 2.3 for crosstalk noise to be below the critical value. Measurements and simulations also indicate that the proposed methodology for terminated design consumes only 1.08 mW for data transfer over point to point interconnects compared to conventional schemes.