Intel 4 620 JM80547PG0722MM Data Sheet
Product codes
JM80547PG0722MM
34
Datasheet
Electrical Specifications
2.13
GTL+ FSB Specifications
Termination resistors are not required for most GTL+ signals, as these are integrated into the
processor silicon. Valid high and low levels are determined by the input buffers that compare a
signal’s voltage with a reference voltage called GTLREF.
processor silicon. Valid high and low levels are determined by the input buffers that compare a
signal’s voltage with a reference voltage called GTLREF.
specifications. The GTL+ reference voltage (GTLREF) should be generated on the system board
using high precision voltage divider circuits. Contact your Intel representative for further details
and documentation.
using high precision voltage divider circuits. Contact your Intel representative for further details
and documentation.
§
Table 2-18. GTL+Bus Voltage Definitions
Symbol
Parameter
Min
Typ
Max
Units
Notes
1
NOTES:
1.
Unless otherwise noted, all specifications in this table apply to all processor frequencies.
GTLREF
Bus Reference
Voltage
Voltage
(0.98 * 0.67) * V
TT
0.67 * V
TT
(1.02 * 0.67) * V
TT
V
2, 3, 4,
5
2.
The tolerances for this specification have been stated generically to enable the system designer to calculate the minimum
and maximum values across the range of V
and maximum values across the range of V
TT
.
3.
GTLREF should be generated from V
TT
by a voltage divider of 1% resistors or 1% matched resistors. Contact your Intel
representative for further details and documentation.
4.
The V
TT
referred to in these specifications is the instantaneous V
TT
.
5.
The Intel 915G/915GV/915GL/915P/915PL and 925X/925XE Express chipset platforms use a pull-up resistor of 100
Ω and
pull-down resistor of 210
Ω. Contact your Intel representative for further details and documentation.
R
PULLUP
On die pull-up for
BOOTSELECT
signal
BOOTSELECT
signal
500
—
5000
Ω
6
6.
These pull-ups are to V
TT
.
R
TT
Termination
Resistance
Resistance
54
60
66
Ω
7
7.
R
TT
is the on-die termination resistance measured at V
TT
/2 of the GTL+ output driver.
COMP[1:0]
COMP Resistance
59.8
60.4
61
Ω
8
8.
COMP resistance must be provided on the system board with 1% resistors. Contact your Intel representative for further de-
tails and documentation.COMP[1:0] resistors are to V
tails and documentation.COMP[1:0] resistors are to V
SS
.
Table 2-19. GTLREF Definition for Intel
®
945G/945P/955X Express Chipset and Intel
®
E7230
Chipset Platforms
Symbol
Parameter
Min
Typ
Max
Units
Notes
1
NOTES:
1.
GTLREF is to be generated from V
TT
by a voltage divider of 1% resistors (one divider for each GTLREF land). Refer to the
appropriate platform design guide for additional implementation details.
GTLREF_PU
GTLREF pull-up resistor
124*0.99
124
124*1.01
Ω
GTLREF_PD
GTLREF pull-down resistor
210*0.99
210
210*1.01
Ω