mpc8378 Freescale Semiconductor, Inc, mpc8378 Datasheet - Page 87

• Manufacturer Part Number: mpc8378
• Description: Powerquicc Ii Pro Processor
• Manufacturer: Freescale Semiconductor, Inc

occurs in the 1–15 MHz range. The source impedance of the clock driver should be 50 Ω to match the
transmission line and reduce reflections which are a source of noise to the system.
Table 71
Freescale Semiconductor
At recommended operating conditions with XV
Rising Edge Rate
Falling Edge Rate
Differential Input High Voltage
Differential Input Low Voltage
Rising edge rate (SD n _REF_CLK) to falling edge rate
(SD n _REF_CLK) matching
Note:
1
2
3
4
Measurement taken from single ended waveform.
Measurement taken from differential waveform.
Measured from –200 mV to +200 mV on the differential waveform (derived from SD n _REF_CLK minus SD n _REF_CLK). The
signal must be monotonic through the measurement region for rise and fall time. The 400 mV measurement window is
centered on the differential zero crossing. See
Matching applies to rising edge rate for SD n _REF_CLK and falling edge rate for SD n _REF_CLK. It is measured using a
200 mV window centered on the median cross point where SDn_REF_CLK rising meets SD n _REF_CLK falling. The median
cross point is used to calculate the voltage thresholds the oscilloscope is to use for the edge rate calculations. The Rise Edge
Rate of SD n _REF_CLK should be compared to the Fall Edge Rate of SD n _REF_CLK, the maximum allowed difference
should not exceed 20% of the slowest edge rate. See
SD n _REF_CLK
SD n _REF_CLK
VIH = +200 mV
VIL = –200 mV
describes some AC parameters common to PCI Express and SATA protocols.
Minus
SD n _REF_CLK
SD n _REF_CLK
0.0 V
V
CROSS MEDIAN
Figure 61. Single-Ended Measurement Points for Rise and Fall Time Matching
MPC8377E PowerQUICC II Pro Processor Hardware Specifications, Rev. 3
Parameter
Figure 60. Differential Measurement Points for Rise and Fall Time
Rise Edge Rate
Table 71. SerDes Reference Clock Common AC Parameters
DD_SRDS
or XV
Figure
DD_SRDS
60.
Figure
V
V
Rise-Fall Matching
CROSS MEDIAN
CROSS MEDIAN
= 1.0 V ± 5%.
Rise Edge Rate
Fall Edge Rate
61.
Symbol
V
V
SD n _REF_CLK
SD n _REF_CLK
V
IH
IL
CROSS MEDIAN
+100 mV
–100 mV
Fall Edge Rate
Min
200
1.0
1.0
—
—
T
FALL
High-Speed Serial Interfaces (HSSI)
–200
Max
4.0
4.0
20
—
T
RISE
V/ns
Unit
V/ns
mV
mV
%
Notes
2, 3
2, 3
1, 4
2
2
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