Datasheet 99
Balanced Technology Extended (BTX) Type I Boxed Processor Specifications

8.1.3 Boxed Processor Support and Retention Module (SRM)

The boxed processor TMA requires a SRM assembly to attach directly to the chassis base pan and
to secure the processor and TMA in the mainboard socket. The boxed processor TMA will ship
with the heatsink attach clip assembly, duct, and screws for attachment. The SRM must be supplied
by the chassis hardware vendor. See the Support and Retention Module (SRM) External Design
Requirements Document, Balanced Technology Extended (BTX) System Design Guide, and the
Intel® Pentium® D Processor and Intel® Pentium® Processor Extreme Edition 840 Thermal and
Mechanical Design Guidelines for more detailed design information regarding the support and
retention module.
8.2 Electrical Requirements

8.2.1 Fan Heatsink Power Supply

The boxed processor's fan heatsink requires a +12 V power supply. A fan power cable will be
shipped with the boxed processor to draw power from a power header on the baseboard. The power
cable connector and pinout are shown in Figure8-4. Baseboards must provid e a matched po wer
header to support the boxed processor. Table 8- 1 contains specifications for the input and output
signals at the fan heatsink connector.
The fan heatsink outputs a SENSE signal that is an open- collector output that pulses at a rate of
2p ulses per fan revolution. A baseboard pull-up resistor provides VOH to match the system board-
mounted fan speed monitor requirements, if applicable. Use of the SENSE signal is optional. If the
SENSE signal is not used, pin 3 of the connector should be tied to GND.
Figure 8-3. Assembly Stack Including the Support and Retention Module
Thermal Module Assembly
•Heatsink & Fan
• Clip
Structu ra l D u c t
Motherboard
SRM
Chassis Pan