Integration Manual

Table Of Contents
TOBY-L3 series - System Integration Manual
TSD-19090601 - R13 System Integration Manual Page 111 of 143
Consider the usage of low value series damping resistors to avoid reflections and other losses in signal
integrity, which may create ringing and loss of a square wave shape.
2.6.6 SGMII interface
2.6.6.1 Guidelines for SGMII circuit design
TOBY-L3 series modules include an Ethernet Media Access Control (MAC) block supporting up to 1 Gbit/s
data rate via a Serial Gigabit Media-Independent Interface compliant with the SGMII Version 1.8 specification
[8].
The module represents an Ethernet MAC controller, which can be connected to a compatible external
Ethernet physical transceiver (PHY) chip to provide communication over Ethernet as illustrated in Figure 56.
TOBY-L3 series
Ethernet
MAC
SGMII
Connector
Ethernet
PHY
Unshielded Twisted Pair
Figure 56: SGMII interface application circuit block diagram
Do not apply loads which might exceed the limit for the maximum available current from V_ETH supply
(see TOBY-L3 series Data Sheet [1]) as this can cause malfunctions in the internal circuitry.
The ESD sensitivity rating of the SGMII pins is 1 kV (HMB according to JESD22-A114). Higher protection
level could be required if the lines are externally accessible and it can be achieved by mounting a very
low capacitance ESD protection (e.g. Tyco Electronics PESD0402-140 ESD) close to the accessible points.
If the SGMII interface pins are not used, they can be left unconnected on the application board.
2.6.6.2 Guidelines for SGMII layout design
The SGMII interface requires the same considerations regarding electro-magnetic interference as any other
high speed digital interface.
Keep the traces short, avoid stubs and avoid coupling with RF lines / parts or sensitive analog inputs, since
the signals can cause the radiation of some harmonics of the digital data frequency.