A two-tap voltage-mode transmitter with adaptive de-emphasis and impedance self-calibration in 45 nm CMOS

This paper describes a low power two-tap voltage-mode transmitter (Tx) in 45 nm CMOS process technology with adaptive de-emphasis and impedance self-calibration in which the adaptive de-emphasis is independent of the impedance self-calibration. The Tx comprises of eight identical slice units where the impedance of each slice unit is controlled by impedance calibration circuit to match the characteristic impedance of the transmission line. Voltage-mode (VM) driver can save 75 % static output power compared to current-mode (CM) driver. The proposed design provides a differential output swing of 800 mV-1200 mV across process, voltage and temperature (PVT) variation with a power consumption of 10 mW at a data rate of 5 Gb/s under a supply voltage of 1 V. The eye of the received data has 0.9 unit interval (UI) timing margin when the data signals are sent over 20" FR4 channel.