Design Guidelines for 78P235x E4/STM1e LIUs

Abstract: Teridian's 78P2351 and 78P2352 are second-generation line interface unit (LIU) ICs for OC-3, STS-3, STM-1, or EF telecom interfaces. This document provides recommendations that can help alleviate unwanted noise due to suboptimal board layout around the LIU. It also provides general guidelines for meeting the stringent return loss and code matrix insertion (CMI) transmit-pulse shape requirements, both of which are largely dependent on PCB design and layout.