SGMII（ Serial Gigabit Media Independent Interface）/ HiSGMII（High SGMII）
Ethernet MAC和PHY之间数据传递的一种MII（Media Independent Interface）接口，SGMII最高支持1000Mbps。
HiSGMII和SGMII接口相同，区别在于时钟，HiSGMII时钟频率为SGMII的2.5倍，速率只支持2.5Gbps。
常用标准
原理图设计
SGMII信号连接如下图：
SGMII各信号的定义见下表：
| Table 13: SGMII Signal Definitions | ||
| Signal Name | Source | Description |
| SGIN± | Switch/MAC | Transmit data. Differential 1.25-Gbd transmit data from the Switch/MAC to the PHY. |
| SGOUt± | PHY | Receive data. Differential 1.25-Gbd receive data from the PHY to the Switch/MAC. |
| SCLK± | PHY | Transmit clock. Differential 625-MHz clock synchronized to the SGOUT± data. Some Switch/MACs can recover the clock from the SGOUT± data and do not need the SCLK±. If this is the case, then these pins can be left floating. |
PCB设计
- 总长度：小于150mm
- 等长：Rx和tx两组组内需等长，小于5mil，组间无要求。
- 阻抗：差分100Ω
- 间距：组间间距至少两倍线宽，推荐3倍线宽。