Analog to Sequence Converter-Based PAM-4 Receiver With Built-In Error Correction

This paper describes an energy-efficient pulse-amplitude modulation (PAM)-4 digital receiver based on sequence detection. The proposed scheme exploits the pre-cursor ISI in the channel to reconstruct a time series of a 5-bit sequence including future MSB. The future MSB information is used to detect and correct error in the current symbol detection with minimal power and latency overhead. This concept is demonstrated with prototype implemented in a 28-nm fully-depleted silicon-on-insulator CMOS using 18-data comparators. Consuming only 82 mW at 28 Gb/s, the receiver can compensate up to 27-dB channel loss with bit error rate (BER) lower than 10-8. With error correction, the receiver can achieve BER lower than 10-10.