TOBY-L4 series - System Integration Manual
UBX-16024839 - R04
Design-in
Page 100 of 143
2.6.6
RGMII interface
The RGMII interface is not supported by the "50" product version.
2.6.6.1
Guidelines for RGMII circuit design
TOBY-L4 series modules include an Ethernet Media Access Control (MAC) block supporting up to 1 Gbit/s data
rate via a Reduced Gigabit Media-Independent Interface compliant with the
RGMII Version 1.3 specification
and the
RMII Revision 1.2 specification
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 59.
Recommended compatible Ethernet PHY chips are:
Marvell 88E1510
Marvell 88E1512
TOBY-L4 series
Ethernet
MAC
RGMII
Connector
Ethernet
PHY
Unshielded Twisted Pair
Figure 59: RGMII interface application circuit block diagram
The ESD sensitivity rating of RGMII interface pins is 1 kV (HMB according to JESD22-A114). A 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 RGMII interface pins are not used, they can be left unconnected on the application board.
2.6.6.2
Guidelines for RGMII layout design
The RGMII / RMII 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.
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.
