Intel
®
E7520 Memory Controller Hub (MCH) Datasheet 265
Electrical Characteristics
NOTES:
1. Refer to Figure 8 1. Differential Clock Waveform and Figure 8 2. Differential Clock Crosspoint Specification.
2. Crossing voltage is defined as the instantaneous voltage when the rising edge of BCLK0 is equal to the
falling edge of BCLK1.
3. VHavg is the statistical average of the VH measured by the oscilloscope.
4. Overshoot is defined as the absolute value of the maximum voltage.
5. Undershoot is defined as the absolute value of the minimum voltage.
6. Ringback Margin is defined as the absolute voltage difference between the maximum Rising Edge Ringback
and the maximum Falling Edge Ringback.
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* scopes and “High” on Tektronix* scopes.
Table 6-14. Clock DC Characteristics
(1)
Symbol
Signal
Group
Parameter Min Nom Max Unit Notes
FSB Clock (HCLKINN/HCLKINP), 100 MHz Reference Clock (EXP_CLKN/EXP_CLKP)
V
IL
(f), (m) Input Low Voltage –0.150 0 V
V
IH
(f), (m) Input High Voltage 0.660 0.710 0.850 V
V
CROSS(abs)
(f), (m) Absolute Crossing Point 0.250 0.550 V 2, 8
V
CROSS(rel)
(f), (m) Relative Crossing Point
0.250 +
0.5x(V
Havg
– 0.710)
0.550 +
0.5x(V
Havg
– 0.710)
V
CROSS
(f), (m) Range of Crossing Points 0.140
V
OS
(f), (m) Overshoot V
IH
+ 0.300 V 4
V
US
(f), (m) Undershoot –0.300 V 5
V
RBM
(f), (m) Ringback Margin 0.200 V 6
V
TR
(f), (m) Threshold Region
V
CROSS
–
0.100
V
CROSS
+
0.100
V 7
Hub Interface Clock
V
IL
(q) CLK66 Input Low Voltage 0.8 V
V
IH
(q) CLK66 Input High Voltage 2.4 V
Table 6-15. SMBus I/O DC Characteristics
Symbol
Signal
Group
Parameter Min Max Unit Notes
V
IH
(u) Input High Voltage 2.1 V3REF+0.3 V
V
IL
(u) Input Low Voltage -0.3 0.8 V
V
OL
(u) Output Low Voltage 0.4 V Ipullup = 4 mA
I
OL
(u) Output Low Current 4 mA Vol = 0.4 V
I
Leak
(u) Leakage Current 10 A
C
pad
(u) Pad Capacitance 5 pF Pad Only
