Datasheet

615
6120F–ATARM–03-Oct-06
AT91SAM7X512/256/128 Preliminary
39. AT91SAM7X512/256/128 Mechanical Characteristics
39.1 Thermal Considerations
39.1.1 Thermal Data
Table 39-1 summarizes the thermal resistance data depending on the package.
39.1.2 Junction Temperature
The average chip-junction temperature, T
J
, in °C can be obtained from the following:
1.
2.
where:
• θ
JA
= package thermal resistance, Junction-to-ambient (°C/W), provided in Table 39-1 on
page 615.
• θ
JC
= package thermal resistance, Junction-to-case thermal resistance (°C/W), provided in
Table 39-1 on page 615.
• θ
HEAT SINK
= cooling device thermal resistance (°C/W), provided in the device datasheet.
•P
D
= device power consumption (W) estimated from data provided in the section Section
38.3 ”Power Consumption” on page 598.
•T
A
= ambient temperature (°C).
Table 39-1. Thermal Resistance Data
Symbol Parameter Condition Package Typ Unit
θ
JA
Junction-to-ambient thermal resistance Still Air LQFP100 38.3 °C/W
θ
JC
Junction-to-case thermal resistance LQFP100 8.7
T
J
T
A
P
D
θ
JA
×()+=
T
J
T
A
P(
D
θ(
HEATSINK
×θ
JC
))++=