On-Dual In-line Memory Module (DIMM) Low-Pass Filter (LPF) using Via Stubs for Enhancing Signal Integrity

A novel on-dual in-line memory module (on-DIMM) low-pass filter (LPF) using via stubs is proposed to enhance signal integrity. Proposed on-DIMM LPF implemented with existing via stubs not only eliminates the via stub effects, but also enhances the signal quality due to its low-pass characteristics without additional manufacturing processes and costs. For verification, both time- and frequency-domain simulation results of proposed DQ signal line with on-DIMM LPF are shown and compared with conventional DQ signal line. Proposed on-DIMM LPF exhibits 0.67 dB improvements at 2.8 GHz (nyquist frequency of 5.6 Gbps) shows relatively flat and improved insertion loss. Simulated eye height is improved for 29 mV and 20 mV and eye width is improved for 4.2 ps (0.02 UI) and 3.6 ps (0.02 UI) respectively at 4.8 Gbps and 5.6 Gbps. Finally, measurements verification with test board of on-DIMM LPF is also conducted and shows improvements in insertion loss and eye diagram