82551QM Datasheet, PDF (101/120 Pages) Intel Corporation – Fast Ethernet Multifunction PCI/CardBus Controller

Networking Silicon — 82551QM
12.4.1.2 X1 Specifications
X1 serves as a signal input from an external crystal or oscillator. Table 75 defines the 82551QM
requirements from this signal.
Table 75. X1 Clock Specifications
Symbol
Parameter
Min Typical Max
Units Notes
T8 Tx1_dc
T9 Tx1_pr
X1 Duty Cycle
X1 Period
40%
60%
40
ns
±30PPM
12.4.2
Timing Parameters
12.4.2.1 Measurement and Test Conditions
Figure 24, Figure 25, and Table 76 define the conditions under which timing measurements are
done. The component test guarantees that all timings are met with minimum clock slew rate
(slowest edge) and voltage swing. The design must guarantee that minimum timings are also met
with maximum clock slew rate (fastest edge) and voltage swing. In addition, the design must
guarantee proper input operation for input voltage swings and slew rates that exceed the specified
test conditions.
Figure 24. Output Timing Measurement Conditions
V_th
CLK
V_test
V_tl
T_val
OUTPUT
DELAY
V_step
Tri-State
OUTPUT
V_test
V_test
T_on
T_off
Datasheet
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