LAN9500 Datasheet, PDF (205/213 Pages) SMSC Corporation – USB 2.0 to 10/100 Ethernet Controller Promiscuous mode

LAN950x
Note 8-19
Note 8-20
Note 8-21
Note 8-22
Note 8-23
Frequency Deviation Over Time is also referred to as Aging.
The total deviation for the Transmitter Clock Frequency is specified by IEEE 802.3u as
+/- 50 PPM.
0^oC for commercial version, -40^oC for industrial version.
+70^oC for commercial version, +85^oC for industrial version.
This number includes the pad, the bond wire and the lead frame. PCB capacitance is not included
in this value. The XO/XI 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.
8.6.2 100UW 25MHZ CRYSTAL SPECIFICATIONS (LAN9500A/LAN9500AI ONLY)
When utilizing a 100uW 25MHz crystal (LAN9500A/LAN9500Ai only), the following circuit design (Figure 8-11) and
specifications (Table 8-24) are required to ensure proper operation.
FIGURE 8-11:
100UW 25MHZ CRYSTAL CIRCUIT
LAN950x
56-PIN QFN
XO
R_S
Y1
XI
C₁
C₂
TABLE 8-24: 100UW CRYSTAL SPECIFICATIONS
Parameter
Symbol
MIN
NOM
MAX
Crystal Cut
Crystal Oscillation Mode
Crystal Calibration Mode
Frequency
Frequency Tolerance @ 25^oC
Frequency Stability Over Temp
Frequency Deviation Over Time
Total Allowable PPM Budget
Shunt Capacitance
Load Capacitance
Drive Level
Equivalent Series Resistance
XO Series Resistor
Operating Temperature Range
F_fund
F_tol
F_temp
F_age
C_O
C_L
P_W
R₁
R_s
AT, typ
Fundamental Mode
Parallel Resonant Mode
-
25.000
-
-
-
+/-50
-
-
+/-50
-
+/-3 to 5
-
-
-
+/-50
-
-
5
8
-
12
-
100
-
-
-
80
495
500
505
Note 8-28
-
Note 8-29
Units
MHz
PPM
PPM
PPM
PPM
pF
pF
uW
Ohm
Ohm
o_C
Notes
Note 8-24
Note 8-24
Note 8-25
Note 8-26
Note 8-27
 2010 - 2015 Microchip Technology Inc.
DS00001875A-page 205