A PAM-4 Receiver with Selective Reference Voltage Adaptation for Low Sensitivity to Sampler Voltage Variations

This paper presents a pulse amplitude modulation-4 (PAM-4) receiver with low sensitivity to sampler voltage variation. Based on time-based LSB decoder [1], it has improved bit error rate (BER) performance in voltage fluctuation environment by selectively applying data level as reference voltage. In addition, a single error sampler is utilized to perform continuous reference voltage adaptation based on random data. By applying the data levels as reference voltage, the adaptation algorithms are simplified by finding only two data levels and can reduce power consumption and hardware complexity. Simulation result shows power consumption of the proposed receiver is only 1.45[pJ/bit] at 20Gb/s. This work is designed using 65nm process.