82583V Datasheet, PDF (33/374 Pages) Intel Corporation – Intel® 82583V GbE Controller

Electrical Specifications—82583V GbE Controller
3.9
Table 18.
Note:
Oscillator/Crystal Specifications
See Figure 7 for recommended crystal placement and layout instructions.
External Crystal Specifications
Parameter Name
Frequency
Vibration Mode
Frequency Tolerance @25 °C
Temperature Tolerance
Series Resistance (ESR)
Crystal Load Capacitance
Shunt Capacitance
Drive Level
Aging
Calibration Mode
Insulation Resistance
Symbol
f_o
Df/f_o @25°C
Df/f_o
R_s
C_load
C_o
D_L
Df/f_o
Recommended
Value
25 [MHz]
Fundamental
±30 [ppm]
±30 [ppm]
18 [pF]
±5 ppm per year
Parallel
Max/Min Range
50 [Ω] max
6 [pF] max
300 [μW] max
±5 ppm per year max
500 [MΩ] min
Conditions
@25 [°C]
@25 [°C]
@25 [MHz]
@ 100 V dc
Intel does not recommend a significantly lower Cload capacitance then 18 pF due to
crystal trimming sensitivity (ppm/pF) versus Cload rating. Lower Cload crystals are
more likely to cause the LAN reference frequency to be out of specification (30 ppm).
Also, a ≥ 5x gain or ≥ 5x negative resistance is NOT necessary from Intel’s LAN
component’s crystal driver. A ≥ 5x gain or ≥ 5x negative resistance can cause crystal
overdrive and accelerate crystal aging (ppm/year). As a result, the crystal circuit might
shift off frequency more quickly than it would with lower driver levels and normal
aging.
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