I960 Datasheet, PDF (37/70 Pages) Intel Corporation – i960 RP/RD I/O PROCESSOR AT 3.3 VOLTS

i960^® Rx I/O Processor at 3.3 V
3.2 Package Thermal Specifications
The device is specified for operation when T_C (case
temperature) is within the range of 0° C to 95° C.
Case temperature may be measured in any
environment to determine whether the processor is
within specified operating range. Measure the case
temperature at the center of the top surface,
opposite the ballpad.
• Attach the thermocouple bead or junction at a 90°
angle by an adhesive bond (such as thermal epoxy
or heat-tolerant tape) to the package top surface
as shown in Figure 5. When a heat sink is
attached, drill a hole through the heat sink to allow
contact with the package above the center of the
die. The hole diameter should be no larger than
3.8 mm as shown in Figure 6.
3.2.1 Thermal Specifications
This section defines the terms used for thermal
analysis.
3.2.1.1 Ambient Temperature
Ambient temperature, T_A, is the temperature of the
ambient air surrounding the package. In a system
environment, ambient temperature is the temper-
ature of the air upstream from the package.
3.2.1.2 Case Temperature
To ensure functionality and reliability, the device is
specified for proper operation when the case
temperature, T_C, is within the specified range in
Table 16, Operating Conditions (pg. 34).
When measuring case temperature, attention to
detail is required to ensure accuracy. If a thermo-
couple is used, calibrate it before taking measure-
ments. Errors may result when the measured
surface temperature is affected by the surrounding
ambient air temperature. Such errors may be due to
a poor thermal contact between thermocouple
junction and the surface, heat loss by radiation, or
conduction through thermocouple leads.
To minimize measurement errors:
• Use a 35 gauge K-type thermocouple or equiv-
alent.
• Attach the thermocouple bead or junction to the
package top surface at a location corresponding to
the center of the die (Figure 5). The center of the
die gives a more accurate measurement and less
variation as the boundary condition changes.
Thermocouple Wire
Epoxy Fillet
Thermocouple Bead
Figure 5. Thermocouple Attachment -
No Heat Sink
Thermocouple
3.8 mm Diameter Hole
Heat Sink
Figure 6. Thermocouple Attachment -
With Heat Sink
3.2.1.3 Thermal Resistance
The thermal resistance value for the case-to-
ambient, θ_CA, is used as a measure of the cooling
solution’s thermal performance.
ADVANCE INFORMATION
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