AT32UC3L064_11 ATMEL [ATMEL Corporation], AT32UC3L064_11 Datasheet - Page 73

• Manufacturer Part Number: AT32UC3L064_11
• Description: 32-bit Atmel AVR Microcontroller
• Manufacturer: ATMEL [ATMEL Corporation]

8. Mechanical Characteristics
8.1
8.1.1
8.1.2
32099HS–12/2011
Thermal Considerations
Thermal Data
Junction Temperature
Table 8-1
Table 8-1.
The average chip-junction temperature, T
where:
From the first equation, the user can derive the estimated lifetime of the chip and decide if a
cooling device is necessary or not. If a cooling device is to be fitted on the chip, the second
equation should be used to compute the resulting average chip-junction temperature T
Symbol
θ
θ
θ
θ
θ
θ
1.
2.
• θ
• θ
• θ
• P
• T
JA
JC
JA
JC
JA
JC
Table
42.
JA
JC
HEAT SINK
A
D
T
T
= ambient temperature (°C).
= device power consumption (W) estimated from data provided in the
= package thermal resistance, Junction-to-ambient (°C/W), provided in
= package thermal resistance, Junction-to-case thermal resistance (°C/W), provided in
J
J
=
=
8-1.
summarizes the thermal resistance data depending on the package.
T
T
A
A
= cooling device thermal resistance (°C/W), provided in the device datasheet.
Parameter
Junction-to-ambient thermal resistance
Junction-to-case thermal resistance
Junction-to-ambient thermal resistance
Junction-to-case thermal resistance
Junction-to-ambient thermal resistance
Junction-to-case thermal resistance
+
Thermal Resistance Data
+
P (
(
P
D
D
×
×
θ (
θ
HEATSINK
JA
)
+
θ
JC
) )
J
, in °C can be obtained from the following:
Condition
Still Air
Still Air
Still Air
AT32UC3L016/32/64
TLLGA48
TLLGA48
Package
TQFP48
TQFP48
QFN48
QFN48
Section 7.4 on page
Table
63.2
21.8
28.3
25.4
12.7
Typ
2.5
8-1.
J
°C/W
°C/W
°C/W
in °C.
Unit
73