Low-Power Encoding for PAM-3 DRAM Bus

The 3-level pulse amplitude modulation (PAM-3) signaling is expected to be widely used in memory interfaces for its greater voltage margins compared to PAM-4. To maximize the benefit of PAM-3, we propose three low-power data encoding algorithms: PAM3-DBI, PAM3-MF, and PAM3-SORT. With the DRAM memory traces from the gem5 computer architecture simulator running benchmarks, we evaluate the energy efficiency of our three PAM-3 encoding techniques. The experimental results show the proposed algorithms can reduce termination power for high-speed memory links significantly by 41% to 90% for benchmark programs.