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RTL8111C-VB-GR View Datasheet(PDF) - Realtek Semiconductor

Part Name
Description
MFG CO.
RTL8111C-VB-GR Datasheet PDF : 47 Pages
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RTL8111C
Datasheet
Symbol
Parameter
100MHz Input
Units Note
Min
Max
Duty Cycle
Duty Cycle
40
60
%
2
Rise-Fall Matching Rising Edge Rate (REFCLK+) to
Falling Edge Rate (REFCLK-) Matching
-
20
%
1, 14
ZC-DC
Clock Source DC Impedance
40
60
1, 11
Note1: Measurement taken from single-ended waveform.
Note2: Measurement taken from differential waveform.
Note3: Measured from -150mV to +150mV on the differential waveform (derived from REFCLK+ minus REFCLK-). The
signal must be monotonic through the measurement region for rise and fall time. The 300mV measurement window is
centered on the differential zero crossing. See Figure 24, page 38.
Note4: Measured at crossing point where the instantaneous voltage value of the rising edge of REFCLK+ equals the
falling edge of REFCLK-. See Figure 20, page 33.
Note5: Refers to the total variation from the lowest crossing point to the highest, regardless of which edge is crossing.
Refers to all crossing points for this measurement. See Figure 20, page 33.
Note6: Defines as the absolute minimum or maximum instantaneous period. This includes cycle to cycle jitter, relative
ppm tolerance, and spread spectrum modulation. See Figure 23, page 37.
Note7: Defined as the maximum instantaneous voltage including overshoot. See Figure 20, page 33.
Note8: Defined as the minimum instantaneous voltage including undershoot. See Figure 20, page 33.
Note9: Defined as the total variation of all crossing voltages of Rising REFCLK+ and Falling REFCLK-. This is the
maximum allowed variance in VCROSS for any particular system. See Figure 21, page 37.
Note10: Refer to Section 4.3.2.1 of the PCI Express Base Specification, Revision 1.1 for information regarding ppm
considerations.
Note11: System board compliance measurements must use the test load card described in Figure 27, page 39. REFCLK+
and REFCLK- are to be measured at the load capacitors CL. Single ended probes must be used for measurements
requiring single ended measurements. Either single ended probes with math or differential probe can be used for
differential measurements. Test load CL=2pF.
Note12: TSTABLE is the time the differential clock must maintain a minimum ±150mV differential voltage after
rising/falling edges before it is allowed to droop back into the VRB ±100mV differential range. See Figure 26, page 38.
Note13: ppm refers to parts per million and is a DC absolute period accuracy specification. 1ppm is 1/1,000,000th of
100.000000MHz exactly, or 100Hz. For 300ppm then we have an error budget of 100Hz/ppm*300ppm=30kHz. The
period is to be measured with a frequency counter with measurement window set to 100ms or greater. The ±300ppm
applies to systems that do not employ Spread Spectrum or that use common clock source. For systems employing Spread
Spectrum there is an additional 2500ppm nominal shift in maximum period resulting from the 0.5% down spread
resulting in a maximum average period specification of +2800ppm
Note14: Matching applies to rising edge rate for REFCLK+ and falling edge rate for REFCLK-. It is measured using a
±75mV window centered on the median cross point where REFCLK+ rising meets REFCLK- 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 REFCLK+ should be compared to the Fall Edge Rate of REFCLK-, the maximum allowed difference should not
exceed 20% of the slowest edge rate. See Figure 22, page 37.
Note15: Refer to PCI Express Card Electromechanical Specification, rev.1.1, for correct measurement environment
setting of each parameter.
Integrated Gigabit Ethernet Controller for PCI Express
36
Track ID: JATR-1076-21 Rev. 1.5

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