Intel 4 3.20 GHz BX80532PG3200F User Manual
Product codes
BX80532PG3200F
Intel
®
Pentium
®
4 Processor on 0.13 Micron Process Datasheet
35
Electrical Specifications
2.12
AGTL+ System Bus Specifications
. Termination resistors are not required for most AGTL+ signals because they are
integrated into the processor silicon.
Valid high and low levels are determined by the input buffers which compare a signal’s voltage
with a reference voltage called GTLREF (known as V
REF
in previous documentation).
lists the GTLREF specifications. The AGTL+ reference voltage (GTLREF) should be
generated on the system board using high precision voltage divider circuits. It is important that the
system board impedance is held to the specified tolerance, and that the intrinsic trace capacitance
system board impedance is held to the specified tolerance, and that the intrinsic trace capacitance
for the AGTL+ signal group traces is known and is well-controlled. For more details on platform
design, see the appropriate platform design guide.
design, see the appropriate platform design guide.
NOTES:
1. Unless otherwise noted, all specifications in this table apply to all processor frequencies.
2. The tolerances for this specification have been stated generically to enable the system designer to calculate
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
CC
.
3. GTLREF should be generated from V
CC
by a voltage divider of 1% tolerance resistors or 1% tolerance,
matched resistors. Refer to the appropriate Platform Design Guide for implementation details.
4. R
TT
is the on-die termination resistance measured at V
OL
of the AGTL+ output driver. Refer to processor I/O
buffer models for I/V characteristics.
5. COMP resistance must be provided on the system board with 1% tolerance resistors. See the appropriate
Platform Design Guide for implementation details.
6. The V
CC
referred to in these specifications is the instantaneous V
CC
.
7. The specifications are for a platform to be forward compatible with future processors. A compatible platform
is one that is designed for some level of compatibility with future processors.
Table 2-14. AGTL+ Bus Voltage Definitions
Symbol
Parameter
Min
Typ
Max
Units
Notes
1
GTLREF
Bus Reference Voltage
2/3 V
CC
–2%
2/3 V
CC
2/3 V
CC
+2%
V
2, 3, 6
GTLREF
Compatible
Compatible
Bus Reference Voltage
0.63 V
CC
–2%
0.63 V
CC
0.63 V
CC
+2%
V
2, 3, 6, 7
R
TT
Termination Resistance
45
50
55
Ω
4
R
TT
Compatible
Termination Resistance
54
60
66
Ω
4, 7
COMP[1:0]
COMP Resistance
50.49
51
51.51
Ω
5
COMP[1:0]
Compatible
Compatible
COMP Resistance
61.3
61.9
62.5
Ω
5, 7
Figure 2-7. Test Circuit
2.4 nH
1.2 pF
Rload = 50
Ω
V
CC
V
CC
420 mils, 50
Ω, 169 ps/in