LAN9115-MT Standard Microsystems (SMSC), LAN9115-MT Datasheet - Page 134

• Manufacturer Part Number: LAN9115-MT
• Manufacturer: Standard Microsystems (SMSC)

Specifications of LAN9115-MT

• Operating Supply Voltage (typ): 3.3V
• Operating Supply Voltage (min): 2.97V
• Operating Supply Voltage (max): 3.63V
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 100
• Lead Free Status / RoHS Status: Compliant

Revision 1.5 (07-11-08)
7.6
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
LAN9115 XTAL1 Pin
Capacitance
LAN9115 XTAL2 Pin
Capacitance
PARAMETER
The LAN9115 can accept either a 25MHz crystal (preferred) or a 25 MHz clock oscillator (±50 PPM)
input. The LAN9115 shares the 25MHz clock oscillator input (CLKIN) with the crystal input XTAL1 (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 LAN9115
crystal input/output signals (XTAL1, XTAL2). See
specifications. Refer to SMSC Application Note AN10.7 - “Parallel Crystal Circuit Input Voltage Control”
and the LAN9115 Reference Schematic 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 reffered 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 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 7.6 LAN9115 Crystal Specifications
SYMBOL
F
F
F
F
P
C
temp
C
R
fund
age
tol
W
O
L
1
DATASHEET
MIN
0.5
0
-
Parallel Resonant Mode
-
-
-
-
-
-
-
-
-
134
Fundamental Mode
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Table 7.6, "LAN9115 Crystal Specifications"
AT, typ
+/-3 to 5
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 LAN9115
Note 7.12
Note 7.13
Note 7.14
Note 7.14
Note 7.11
Note 7.11
NOTES
for crystal
Datasheet