Intel Pentium 4 Processor in the 478-Pin Package Thermal Design Guidelines

Intel

Pentium

4 Processor in the 478-Pin Package Thermal Design Guidelines

Design Guide 21

2.3.3 Processor Case Temperature Measurement Guidelines

To ensure functionality and reliability, the Intel



Pentium



4 processor in the 478-pin package is

specified for proper operation when T

is maintained at or below the value listed in the processor

datasheet. The measurement location for T

is the geometric center of the IHS. Figure 1 shows the

location for

measurement.

Special care is required when measuring the T

to ensure an accurate temperature measurement.

Thermocouples are often used to measure T

. Before any temperature measurements are made, the

thermocouples must be calibrated. When measuring the temperature of a surface, which is at a

different temperature from the surrounding local ambient air, errors could be introduced in the

measurements. The measurement errors could be caused by poor thermal contact between the

thermocouple junction and the surface of the integrated heat spreader, heat loss by radiation,

convection, by conduction through thermocouple leads, or by contact between the thermocouple

cement and the heatsink base. To minimize these measurement errors, the approach outlined in the

next section is recommended.

2.3.3.1 Thermocouple Attachment

This section describes the procedure for attaching a thermocouple to the IHS for the case

temperature (T

) measurement.

1. Obtain the necessary items needed for the quantity of thermocouple attaches desired:

• Fine point tweezers

• Exacto* knife (#11 blade)

• Thermocouples (Type K, 36 gauge, 36 inch, Teflon* insulation). Ensure that the

thermocouple has been properly calibrated

• 3M* Kapton* tape (or equivalent) cut into strips (1/8 inch X ½ inch)

• Epoxy (Omegabond* 101 or equivalent)

• Curing oven or equivalent.

2. Use a scribe to mark at the center of the package (IHS side) where the bead of the

thermocouple will be placed. Determine the center of the package by drawing two diagonal

lines across the length of the package. The intersection of the two lines is the package center.

(See following figure).