The SGMII Output spec is slightly ambiguous, the purpose of this FAQ is to clear up the terminology.
Our data sheet has the following spec:
| SGMII OUTPUT | Min | Typ | Max | Unit | |
| Output Differential Voltage | SO_P and SO_N AC coupled | 1060 | 1100 | 1140 | mV |
This means that the Peak-to-Peak difference, SO_P - SO_N, will fall between the values in the table above. Meaning that the SO_P & SO_N signals are roughly ±550 mV.