Intel BFCBASE - Motherboard - 7300 Datasheet page 18

Electrical Specifications
outputs. Please refer to Table 2-12 for the DC specifications for these signals. A voltage
range is provided in Table 2-3 and changes with frequency. The specifications have
been set such that one voltage regulator can operate with all supported frequencies.
Individual processor VID values may be calibrated during manufacturing such that two
devices at the same core frequency may have different default VID settings. This is
reflected by the VID range values provided in Table 2-3.
The processor uses six voltage identification signals, VID[6:1], to support automatic
selection of power supply voltages. Table 2-3 specifies the voltage level corresponding
to the state of VID[6:1]. A '1' in this table refers to a high voltage level and a '0' refers
to a low voltage level. The definition provided in Table 2-3 is not related in any way to
® ®
previous Intel Xeon processors or voltage regulator designs. If the processor socket
is empty (VID[6:1] = 111111), or the voltage regulation circuit cannot supply the
voltage that is requested, the voltage regulator must disable itself. See the Voltage
Regulator Module (VRM) and Enterprise Voltage Regulator-Down (EVRD) 11.0 Design
Guidelines for further details.
Although the Voltage Regulator Module (VRM) and Enterprise Voltage Regulator-Down
(EVRD) 11.0 Design Guidelines defines VID [7:0], VID 7 and VID 0 are not used on the
Dual-Core Intel® Xeon® Processor 7200 Series and Quad-Core Intel® Xeon®
Processor 7300 Series.
The Dual-Core Intel® Xeon® Processor 7200 Series and Quad-Core Intel® Xeon®
Processor 7300 Series provides the ability to operate while transitioning to an adjacent
VID and its associated processor core voltage (V ). This will represent a DC shift in
CC
the load line. It should be noted that a low-to-high or high-to-low voltage state change
may result in as many VID transitions as necessary to reach the target core voltage.
Transitions above the specified VID are not permitted. Table 2-10 includes VID step
sizes and DC shift ranges. Minimum and maximum voltages must be maintained as
shown in Table 2-2 and Table 2-3.
The VRM or EVRD utilized must be capable of regulating its output to the value defined
by the new VID. DC specifications for dynamic VID transitions are included in Table 2-9
and Table 2-10, while AC specifications are included in Table 2-25. Refer to the Voltage
Regulator Module (VRM) and Enterprise Voltage Regulator-Down (EVRD) 11.0 Design
Guidelines for further details.
Power source characteristics must be guaranteed to be stable whenever the supply to
the voltage regulator is stable.
18 Document Number: 318080-002