641 datasheet(82/106 Pages) INTEL

82 / 106 page

Thermal Specifications and Design Considerations

Datasheet

5.2.4

PROCHOT# Signal

An external signal, PROCHOT# (processor hot), is asserted when the processor die

temperature has reached its maximum operating temperature. If the Thermal Monitor

is enabled (note that the Thermal Monitor must be enabled for the processor to be

operating within specification), the TCC will be active when PROCHOT# is asserted. The

processor can be configured to generate an interrupt upon the assertion or de-

assertion of PROCHOT#. Refer to the Intel® 64 and IA-32 Architecture Software

Developer’s Manuals for specific register and programming details.

The processor implements a bi-directional PROCHOT# capability to allow system

designs to protect various components from over-temperature situations. The

PROCHOT# signal is bi-directional in that it can either signal when the processor has

reached its maximum operating temperature or be driven from an external source to

activate the TCC. The ability to activate the TCC via PROCHOT# can provide a means

for thermal protection of system components.

One application is the thermal protection of voltage regulators (VR). System designers

can create a circuit to monitor the VR temperature and activate the TCC when the

temperature limit of the VR is reached. By asserting PROCHOT# (pulled-low) and

activating the TCC, the VR can cool down as a result of reduced processor power

consumption. Bi-directional PROCHOT# can allow VR thermal designs to target

maximum sustained current instead of maximum current. Systems should still provide

proper cooling for the VR, and rely on bi-directional PROCHOT# only as a backup in

case of system cooling failure. Refer to the Voltage Regulator-Down (VRD) 10.1 Design

Guide For Desktop and Transportable LGA775 Socket for details on implementing the

bi-directional PROCHOT# feature.

5.2.5

THERMTRIP# Signal

Regardless of whether or not Thermal Monitor or Thermal Monitor 2 is enabled, in the

event of a catastrophic cooling failure, the processor will automatically shut down when

the silicon has reached an elevated temperature (refer to the THERMTRIP# definition in

Table 25). At this point, the FSB signal THERMTRIP# will go active and stay active as

described in Table 25. THERMTRIP# activation is independent of processor activity and

does not generate any bus cycles.

5.2.6

TCONTROL and Fan Speed Reduction

TCONTROL is a temperature specification based on a temperature reading from the

thermal diode. The value for TCONTROL will be calibrated in manufacturing and

configured for each processor. When TDIODE is above TCONTROL, TC must be at or below

TC-MAX as defined by the thermal profile in Table 28 and Figure 12; otherwise, the

processor temperature can be maintained at TCONTROL (or lower) as measured by the

thermal diode.

The purpose of this feature is to support acoustic optimization through fan speed

control. Contact your Intel representative for further details and documentation.

5.2.7

Thermal Diode

The processor incorporates an on-die PNP transistor whose base emitter junction is

used as a thermal "diode", with its collector shorted to Ground. A thermal sensor

located on the system board may monitor the die temperature of the processor for

thermal management and fan speed control. Table 30, Table 31, Table 32, and Table 33

provide the "diode" parameter and interface specifications. Two different sets of "diode"

parameters are listed in Table 30 and Table 31. The Diode Model parameters (Table 30)

apply to traditional thermal sensors that use the Diode Equation to determine the

641 Datasheet(PDF) 82 Page - Intel Corporation

641 Datasheet(HTML) 82 Page - Intel Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL