lan9217 Standard Microsystems Corp., lan9217 Datasheet - Page 136

• Manufacturer Part Number: lan9217
• Description: Lan9217 16-bit High-performance Single-chip 10/100 Ethernet Controller With Hp Auto-mdix Support
• Manufacturer: Standard Microsystems Corp.

Revision 2.3 (08-06-08)
7.7
Crystal Cut
Crystal Oscillation Mode
Crystal Calibration Mode
Frequency
Frequency Tolerance @ 25
Frequency Stability Over Temp
Frequency Deviation Over Time
Total Allowable PPM Budget
Shunt Capacitance
Load Capacitance
Drive Level
Equivalent Series Resistance
Operating Temperature Range
LAN9217 XTAL1/CLKIN Pin
Capacitance
LAN9217 XTAL2 Pin
Capacitance
PARAMETER
The LAN9217 can accept either a 25MHz crystal (preferred) or a 25 MHz single-ended clock oscillator
(±50 PPM) input. The LAN9217 shares the 25MHz clock oscillator input (CLKIN) with the crystal input
XTAL1/CLKIN. 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 LAN9217
crystal input/output signals (XTAL1, XTAL2). See
crystal specifications. Refer to application note AN10.7 - “Parallel Crystal Circuit Input Voltage Control”
for additional information.
Note 7.11 The maximum allowable values for Frequency Tolerance and Frequency Stability are
Note 7.12 Frequency Deviation Over Time is also referred to as Aging.
Note 7.13 The total deviation for the Transmitter Clock Frequency is specified by IEEE 802.3u as
Note 7.14 This number includes the pad, the bond wire and the lead frame. PCB capacitance is not
Clock Circuit
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).
+/- 50 PPM.
included in this value. The XTAL1/CLKIN and XTAL2 pin and PCB capacitance values are
required to accurately calculate the value of the two external load capacitors. These two
external load capacitors determine the accuracy of the 25.000 MHz frequency.
o
C
Table 7.7 LAN9217 Crystal Specifications
SYMBOL
F
F
F
F
P
C
temp
C
R
fund
age
tol
W
O
L
1
DATASHEET
MIN
0.5
16-bit High-Performance Single-Chip 10/100 Ethernet Controller with HP Auto-MDIX Support
0
-
Parallel Resonant Mode
-
-
-
-
-
-
-
-
-
136
Fundamental Mode
AT, typ
+/-3 to 5
Table 7.7, "LAN9217 Crystal Specifications"
25.000
20 typ
NOM
7 typ
3 typ
3 typ
-
-
-
-
-
-
+/-50
+/-50
+/-50
MAX
+70
30
-
-
-
-
-
-
-
UNITS
PPM
PPM
PPM
PPM
Ohm
MHz
mW
pF
pF
o
pF
pF
C
SMSC LAN9217
Note 7.12
Note 7.13
Note 7.14
Note 7.14
Note 7.11
Note 7.11
NOTES
Datasheet
for