Intel 6 SERIES CHIPSET - DATASHEET 01-2011 Datasheet page 323

Electrical Characteristics
Table 8-24. Clock Timings (Sheet 4 of 4)
Sym
Slew_Rise
Slew_Fall
NOTES:
1. The CLK48 expects a 40/60% duty cycle.
2. The maximum high time (t18 Max) provide a simple ensured method for devices to detect
bus idle conditions.
3. BCLK Rise and Fall times are measured from 10%VDD and 90%VDD.
4. SUSCLK duty cycle can range from 30% minimum to 70% maximum.
5. Edge rates in a system as measured from 0.8 V to 2.0 V.
6. The active frequency can be 5 MHz, 50 MHz, or 62.5 MHz depending on the interface
speed. Dynamic changes of the normal operating frequency are not allowed.
7. Testing condition: 1 KOhm pull up to Vcc, 1 KOhm pull down and 10 pF pull down and
1/2 inch trace (see
8. Jitter is specified as cycle to cycle as measured between two rising edges of the clock being
characterized. Period min and max includes cycle to cycle jitter and is also measured
between two rising edges of the clock being characterized.
9. On all jitter measurements care should be taken to set the zero crossing voltage (for rising
edge) of the clock to be the point where the edge rate is the fastest. Using a Math function
= Average(Derivavitive(Ch1)) and set the averages to 64, place the cursors where the
slope is the highest on the rising edge – usually this lower half of the rising edge. The
reason this is defined is for users trying to measure in a system it is impossible to get the
probe exactly at the end of the Transmission line with large Flip Chip components, this
results in a reflection induced ledge in the middle of the rising edge and will significantly
increase measured jitter.
10. Phase jitter requirement: The designated Gen2 outputs will meet the reference clock jitter
requirements from the PCI Express Gen2 Base Specification. The test is to be performed
on a component test board under quiet conditions with all clock outputs on. Jitter analysis
is performed using a standardized tool provided by the PCI SIG. Measurement
methodology is defined in Intel document "PCI Express Reference Clock Jitter
Measurements". Note that this is not for CLKOUT_PCIE[7:0].
11. Testing condition: 1-k pull-up to Vcc, 1 k pull down and 10 pF pull-down and
1/2 inch trace (see
12. Total of crystal cut accuracy, frequency variations due to temperature, parasitics, load
capacitance variations and aging is recommended to be less than 90 ppm.
13. Spread Spectrum (SSC) is referenced to rising edge of the clock.
14. Spread Spectrum (SSC) of 0.25% on CLKOUT_PCIE[7:0] and CLKOUT_PEG_[B:A] is used
for WiMAX friendly clocking purposes.
15. When SMLink0 is configured to run in Fast Mode using a soft strap, the operating frequency
is in the range of 300 kHz–400 kHz.
Datasheet
Parameter
Output Rise Slew Rate (0.2Vcc -
0.6Vcc)
Output Fall Slew Rate (0.6Vcc -
0.2Vcc)
Figure 8-31 for more detail).
Figure 8-31 for more detail).
Min Max
SPI_CLK
1 4
1 4
Unit
Notes Figure
V/ns 11 8-31
V/ns 11 8-31
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