Single-ended impedance-modulation equalization for low-power differential voltage-mode drivers

In this paper, a modified structure for low-swing voltage-mode drivers in high-speed serial links is proposed, which offers lower static power and reduces the number of transistors compared to the conventional design. This structure adopts an impedance-modulated 2-tap equalizer with analog tap control. The impedance modulation technique is applied to only one input of the driver. Therefore, six transistors are eliminated in the driver and their control impedance circuitry is removed. Simulation results of an 8-Gb/s serial link in a 0.13-μm CMOS technology confirm that the proposed structure reduces the width of the transistors and the static power consumption by 20% and 11%, respectively. Also when a 200 mVp-p differential signal is sent over a channel with 10 dB attenuation at 4 GHz, the eye diagram of the received data has a 113.5 mV eye opening.