Intel
®
Pentium
®
III Processor with 512KB L2 Cache Dual Processor Platform Design Guide
7-1
Processor Migration Considerations
7
7.1
Overview
This section describes the required changes to AGTL+ only processor platforms in order to convert them
to AGTL compatible processor platforms. The information in this section should be used in conjunction
with specifications presented in the latest version of the Intel
®
Pentium
®
III Processor with 512KB L2
Cache Datasheet and the Pentium
®
III Processor for the PGA370 Socket Datasheet, as well as
information provided in other design guides such as the VRM 8.5 DC-DC Converter Design Guidelines.
Design decisions should always be based on information contained in the latest Intel
®
Pentium
®
III
Processor with 512KB L2 Cache Datasheet.
For reliable Intel
®
Pentium
®
III Processor with 512KB L2 Cache operation, the designer must ensure that
the requirements in this guideline are fully satisfied.
7.2
Implement VRM 8.5
The Intel
®
Pentium
®
III Processor with 512KB L2 Cache requires a VRM 8.5 compliant VRM for its power
supply. Compliance with the following subsections is required for proper processor operation. This new
VRM specification contains several features needed to meet the Intel® Pentium® III Processor with
512KB L2 Cache's operating requirements.
•
Higher currents
•
Smaller voltage increments. VID25MV pin added to enable 25 mV step
•
Active voltage positioning (load line transient specs)
•
VTT_PWRGD timer. Supports new BSEL and VID implementation. Asserted 1 ms after VTT is stable
•
New connector and keepouts
•
New voltage ranges
The specification for the new VRM design can be found in VRM 8.5 DC-DC Converter Design Guideline,
which is available from Intel.
7.2.1
VRM 8.5 Voltage Range
Figure 7-1
shows the operational voltage ranges for AGTL compatible processors.
