357 - Is is OK to terminate VCCIB/VCCOB (VDDIB/VDDOB) to power on unused SERDES channels of all Lattice SERDES/PCS based devices (LatticeECP2M / LatticeECP3 / LatticeSC/M)?
As per Lattice Technical Note TN1144, VCCIB and VCCOB are only used to supply input/output termination voltage to match the tranmission lines.
By default, if a channel is unused during the IPexpress PCS generation phase, the autoconfig file (.txt) will power down this channel. As a result, whether you terminate VCCIB/OB of the unused channels or leave them floating makes no difference.
Another situation is where you enable a channel in IPexpress and terminate VCCIB/VCCOB to power. If you later decide not to use the channel in hardware, then terminating VCCIB/VCCOB also has a minimal effect due to the lack of activity on that channel.
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