IPC International Community magazine an association member publication
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86 I-CONNECT007 MAGAZINE I JUNE 2026 A s data rates climb from 112G PAM4 toward 224G PAM4 and beyond, electronics de- signers are discovering that traditional strip- line and microstrip geometries are no longer suffi- cient. The physics simply break. Rise times are now in the single digit picosecond range, loss budgets are measured in millimeters, and even tiny disconti- nuities can collapse a PAM4 eye. Next-generation Ethernet is moving to 224G sig- naling, enabling the transition to 1.6 terabit Ether- net. As data complexity explodes and servers hit their physical density limits, the industry can no longer rely on simply adding more pluggable mod- ules. The only viable path forward is faster SerDes, which converts parallel data into a high-speed seri- al stream for transmission and reconstructs the par- allel data at the receiver. Beyond raw bandwidth, 224G delivers architectural advantages: fewer ca- bles, fewer switches, and more efficient network fabrics. Its inherent backward compatibility ensures that operators can integrate 224G into existing Eth- ernet environments without disruption. Higher data rates demand modulation schemes with greater spectral efficiency. For decades, non- return-to-zero (NRZ) has been the workhorse for standards like PCIe and Ethernet 802.3, but as bit rates surpassed 32 Gbps, PAM4 signaling has be- come the standard. This scheme uses multiple sig- nal levels or phases to encode more bits per symbol, thereby increasing the channel's spectral efficiency and data rate. However, they also increase the com- plexity and sensitivity of the signal-processing and recovery circuits, requiring careful PCB design to ensure proper signal quality and synchronization. NRZ is a modulation technique that has two BY BA R RY O L N E Y, I N - C I RC U I T D ES I G N PT Y LT D | AU ST R A L I A SKIP-LAYER ROUTING The Waveguide Structure That Makes 224G Possible B E YO N D D ES I G N