AT91SAM7S32-AI ATMEL [ATMEL Corporation], AT91SAM7S32-AI Datasheet - Page 424

• Manufacturer Part Number: AT91SAM7S32-AI
• Description: AT91 ARM Thumb-based Microcontrollers
• Manufacturer: ATMEL [ATMEL Corporation]

AT91SAM7S32 Mechanical Characteristics
Thermal Considerations
Thermal Data
424
AT91SAM7S32 Preliminary
In Table 102, the device lifetime is estimated using the MIL-217 standard in the “moderately
controlled” environmental model (this model is described as corresponding to an installation in
a permanent rack with adequate cooling air), depending on the device Junction Temperature.
(For details see the section “Junction Temperature” on page 425.)
Note that the user must be extremely cautious with this MTBF calculation. It should be noted
that the MIL-217 model is pessimistic with respect to observed values due to the way the
data/models are obtained (test under severe conditions). The life test results that have been
measured are always better than the predicted ones.
Table 102. MTBF Versus Junction Temperature
Table 103 summarizes the thermal resistance data depending on the package.
Table 103. Thermal Resistance Data
Symbol
JA
JC
Junction Temperature (T
Parameter
Junction-to-ambient thermal resistance
Junction-to-case thermal resistance
100
125
150
175
J
) (°C)
Estimated Lifetime (MTBF) (Year)
Condition
Still Air
17.5
9
5
3
Package
LQFP48
LQFP48
6071A–ATARM–28-Oct-04
49.5
12.7
Typ
°C/W
Unit