High-Performance Single-Chip 10/100 Ethernet Controller with HP Auto-MDIX and Industrial Temperature Support
Datasheet
Table 7.6 10BASE-T Transceiver Characteristics
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
NOTES
Transmitter Peak Differential
Output Voltage
VOUT
2.2
2.5
2.8
V
Note 7.11
Receiver Differential Squelch
Threshold
VDS
300
420
585
mV
Note 7.11 Measured at the line side of the transformer, line replaced by 100Ω (+/- 1%) resistor.
7.6
Clock Circuit
The LAN9218i can accept either a 25MHz crystal (preferred) or a 25 MHz single-ended clock oscillator
(±50 PPM) input. The LAN9218i shares the 25MHz clock oscillator input (CLKIN) with the crystal input
XTAL1/CLKIN (pin 6). If the single-ended clock oscillator method is implemented, XTAL2 should be left
unconnected and CLKIN should be driven with a nominal 0-3.3V clock signal. The input clock duty
cycle is 40% minimum, 50% typical and 60% maximum.
It is recommended that a crystal utilizing matching parallel load capacitors be used for the LAN9218i
crystal input/output signals (XTAL1, XTAL2). See Table 7.7, "LAN9218i Crystal Specifications" for
crystal specifications. Refer to application note AN10.7 - “Parallel Crystal Circuit Input Voltage Control”
for additional information.
Table 7.7 LAN9218i Crystal Specifications
PARAMETER
SYMBOL
MIN
NOM
AT, typ
Fundamental Mode
Parallel Resonant Mode
MAX
UNITS
NOTES
Crystal Cut
Crystal Oscillation Mode
Crystal Calibration Mode
Frequency
Ffund
Ftol
-
25.000
-
MHz
PPM
PPM
PPM
PPM
pF
Frequency Tolerance @ 25oC
Frequency Stability Over Temp
Frequency Deviation Over Time
Total Allowable PPM Budget
Shunt Capacitance
-
-
+/-50
Note 7.12
Note 7.12
Note 7.13
Note 7.14
Ftemp
Fage
-
-
+/-50
-
+/-3 to 5
-
-
-
+/-50
CO
CL
-
-
7 typ
-
-
Load Capacitance
20 typ
pF
Drive Level
PW
R1
0.5
-
-
-
mW
Ohm
oC
Equivalent Series Resistance
Operating Temperature Range
-
-
30
+85
-
-40
-
LAN9218i XTAL1/CLKIN Pin
Capacitance
3 typ
pF
Note 7.15
Note 7.15
LAN9218i XTAL2 Pin
Capacitance
-
3 typ
-
pF
Note 7.12 The maximum allowable values for Frequency Tolerance and Frequency Stability are
application dependant. Since any particular application must meet the IEEE +/-50 PPM
Total PPM Budget, the combination of these two values must be approximately +/-45 PPM
(allowing for aging).
SMSC LAN9218i
131
Revision 1.8 (06-06-07)
DATASHEET
SMSC [ SMSC CORPORATION ]
