Intel E5472 Data Sheet - Page 41

Electrical Test Circuit, Differential Clock Waveform

Page 41 highlights

Quad-Core Intel® Xeon® Processor 5400 Series Electrical Specifications 7. Threshold Region is defined as a region entered around the crossing point voltage in which the differential receiver switches. It includes input threshold hysteresis. 8. The crossing point must meet the absolute and relative crossing point specifications simultaneously. 9. VHavg can be measured directly using "Vtop" on Agilent and "High" on Tektronix oscilloscopes. 10. For VIN between 0 V and VH. 11. ΔVCROSS is defined as the total variation of all crossing voltages as defined in note 3. 12. Measured from -200 mV to +200 mV on the differential waveform (derived from REFCLK+ minus REFCLK-). 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 Figure 2-15. Figure 2-12. Electrical Test Circuit Vtt Vtt 55 Ohms, 160 ps/in, 600 mils 0.3nH 0.9nH 0.6nH Rtt = 55 Ohms Buffer Long Package 1.3pF 0.2pF RLoad AC Timings specified at this point (@ Buffer pad) Figure 2-13. Differential Clock Waveform BCLK1 Threshold Region BCLK0 Crossing Voltage Crossing Voltage Tp Tp = T1: BCLK[1:0] period Ringback Margin Overshoot VH Rising Edge Ringback Falling Edge Ringback, VL Undershoot 41

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41
Quad-Core Intel® Xeon® Processor 5400 Series Electrical Specifications
7.
Threshold Region is defined as a region entered around the crossing point voltage in which the differential
receiver switches. It includes input threshold hysteresis.
8.
The crossing point must meet the absolute and relative crossing point specifications simultaneously.
9.
V
Havg
can be measured directly using “Vtop” on Agilent and “High” on Tektronix oscilloscopes.
10.
For V
IN
between 0 V and V
H
.
11.
Δ
V
CROSS
is defined as the total variation of all crossing voltages as defined in note 3.
12.
Measured from -200 mV to +200 mV on the differential waveform (derived from REFCLK+ minus REFCLK-).
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
Figure 2-15
.
Figure 2-12. Electrical Test Circuit
Figure 2-13. Differential Clock Waveform
Vtt
55 Ohms, 160 ps/in, 600 mils
0.3nH
0.9nH
0.6nH
Rtt = 55 Ohms
1.3pF
0.2pF
AC Timings specified at this point (@ Buffer pad)
Vtt
Buffer
Long Package
R
Load
Crossing
Voltage
Threshold
Region
VH
VL
Overshoot
Undershoot
Ringback
Margin
Rising Edge
Ringback
Falling Edge
Ringback,
BCLK0
BCLK1
Crossing
Voltage
Tp
Tp
= T1: BCLK[1:0] period