Datasheet

Datasheet 31
Electrical Specifications
NOTES:
1. Unless otherwise noted, all specifications in this table apply to all processor frequencies.
2. V
IL
is defined as the voltage range at a receiving agent that will be interpreted as a logical
low value.
3. The V
CCP
referred to in these specifications refers to instantaneous V
CCP
.
4. V
IH
is defined as the voltage range at a receiving agent that will be interpreted as a logical
high value.
5. V
IH
and V
OH
may experience excursions above V
CCP
.
6. All outputs are open drain.
7. I
OL
is measured at 0.10 * V
CCP.
I
OH
is measured at 0.90 * V
CCP.
8. Leakage to V
SS
with pin held at V
CCP
.
9. Leakage to V
CCP
with pin held at 300 mV
3.8.3.1 GTL+ Front Side Bus Specifications
In most cases, termination resistors are not required as these are integrated into the
processor silicon. See Table 9 for details on which GTL+ signals do not include on-die
termination.
Valid high and low levels are determined by the input buffers by comparing with a
reference voltage called GTLREF. Table 14 lists the GTLREF specifications for 50 Ohm
platform. The GTL+ reference voltage (GTLREF) should be generated on the system
board using high precision voltage divider circuits.
NOTES:
1. Unless otherwise noted, all specifications in this table apply to all processor frequencies.
2. GTLREF is to be generated from V
CCP
by a voltage divider of 1% resistors (one divider for
each GTLEREF pin).
3. R
TT
is the on-die termination resistance measured at V
CCP
/3 of the GTL+ output driver.
4. COMP resistance must be provided on the system board with 1% resistors. COMP[3:0]
resistors are tied to V
SS
.
Table 13. CMOS Signal Group DC Specifications
Symbol Parameter Min Max Unit Notes
1
V
IL
Input Low Voltage -0.10 V
CCP
* 0.30 V 2, 3
V
IH
Input High Voltage V
CCP
* 0.70 V
CCP
+ 0.10 V 4, 5, 3
V
OL
Output Low Voltage -0.10 V
CCP
* 0.10 V 3
V
OH
Output High Voltage 0.90 * V
CCP
V
CCP
+ 0.10 V 6, 5, 3
I
OL
Output Low Current 1.70 4.70 mA 3, 7
I
OH
Output High Current 1.70 4.70 mA 3, 7
I
LI
Input Leakage Current N/A ± 100 µA 8
I
LO
Output Leakage Current N/A ± 100 µA 9
Table 14. GTL Bus Voltage Definitions
Symbol Parameter Min Typ Max Units Notes
1
GTLREF_PU GTLREF pull up resistor -1% 1000 +1% Ω
GTLREF_PD GTLREF pull down resistor -1% 2000 +1% Ω 2, 4
R
TT
Termination Resistance 48 50 62 Ω 3
COMP[0,2] Termination Resistance -1% 27.4 +1% Ω 4
COMP[1,3] Termination Resistance -1% 54.9 +1% Ω 4