Small Footprint RMII 10/100 Ethernet Transceiver with HP Auto-MDIX Support
Datasheet
6.3.2.2
10M RMII Transmit Timing (50MHz REF_CLK OUT)
REFCLKO
T14.1
T14.2
Data In -
TXD[1:0]
TX_EN
Valid Data
Figure 6.9 10M RMII Transmit Timing Diagram (50MHz REF_CLK OUT)
Table 6.9 10M RMII Transmit Timing Values (50MHz REF_CLK OUT)
PARAMETER
DESCRIPTION
MIN
TYP
MAX
UNITS
NOTES
T14.1
Transmit signals required setup to
rising edge of REFCLKO
7
ns
T14.2
Transmit signals required hold
after rising edge of REFCLKO
2.5
ns
CLKIN frequency
50
MHz
6.4
RMII CLKIN Requirements
Table 6.10 RMII CLKIN (REF_CLK) Timing Values
PARAMETER
DESCRIPTION
CLKIN frequency
MIN
TYP
MAX
UNITS
MHz
ppm
%
NOTES
50
CLKIN Frequency Drift
CLKIN Duty Cycle
CLKIN Jitter
± 50
60
40
150
psec
p-p – not RMS
SMSC LAN8720/LAN8720i
Revision 1.0 (05-28-09)
DATA6S3HEET
SMSC [ SMSC CORPORATION ]
