Datasheet

Electrical Characteristics
R
122 Intel
®
82845 MCH for DDR Datasheet
6.4 DC Characteristics
Table 21. DC Characteristics
Symbol Signal
Group
Parameter Min Nom Max Unit Notes
I/O Buffer Supply Voltage
VCCSM (u) DDR I/O Supply Voltage 2.375 2.5 2.625 V
VCC1_8 (t) 1.8V I/O Supply Voltage 1.71 1.8 1.89 V
VCC1_5 (s) Core and AGP Voltage 1.425 1.5 1.575 V
VTT (r) Host AGTL+ Termination
Voltage
N/A N/A 1.75 V
Reference Voltages
HVREF (d) Host Address and Data
Reference Voltage
2/3 x VTT – 2% 2/3 x VTT 2/3 x VTT + 2% V
HSWING (d) Host Compensation
Reference Voltage
1/3 x VTT – 2% 1/3 x VTT 1/3 x VTT + 2% V
HIREF (j) Hub Interface Reference
Voltage
0.48 x VCC1_8 1/2 x VCC1_8 0.52 x VCC1_8 V
SDREF (n) DDR Reference Voltage 0.48 x VCCSM 1/2 x VCCSM 0.52 x VCCSM V
AGPREF (h) AGP Reference Voltage 0.48 x VCC1_5 1/2 x VCC1_5 0.52 x VCC1_5 V
Host Interface
V
IL_H
(a,c) Host AGTL+ Input Low
Voltage
(2/3 x VTT) – 0.1 V
V
IH_H
(a,c) Host AGTL+ Input High
Voltage
(2/3 x VTT) + 0.1 V
V
OL_H
(a,b) Host AGTL+ Output Low
Voltage
(1/3 x VTT) + 0.1 V
V
OH_H
(a,b) Host AGTL+ Output High
Voltage
VTT–0.1 V
I
OL_H
(a,b) Host AGTL+ Output Low
Current
VTT
max
/ 0.75Rtt
min
mA Rtt
min
=45Ω
I
LEAK_H
(a,c) Host AGTL+ Input
Leakage Current
±15 µA V
OL
<Vpad<
VTT
C
PAD
(a,c) Host AGTL+ Input
Capacitance
1.0 pF