16

Atmel SAM D20 [DATASHEET Summary]

42129JS–SAM–12/2013

8.

Packaging Information

8.1

Thermal Considerations

8.1.1

Thermal Resistance Data

Table 8-1 summarizes the thermal resistance data depending on the package.

Table 8-1.

Thermal Resistance Data

8.1.2

Junction Temperature

The average chip-junction temperature, T

Equation 1

Equation 2

where:

θ

θ

θ

P

T

From “Equation 1” , 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, “Equation 2” should be used to compute the resulting average chip-

junction temperature T

Package Type

θ

JA

θ

JC

32-pin TQFP

68

°C/W

25.8

°C/W

48-pin TQFP

78.8

°C/W

12.3

°C/W

64-pin TQFP

66.7

°C/W

11.9

°C/W

32-pin QFN

37.2

°C/W

3.1

°C/W

48-pin QFN

33

°C/W

11.4

°C/W

64-pin QFN

33.5

°C/W

11.2

°C/W

T

J

T

A

P

D

θ

JA

×

()

+

=

T

J

T

A

P

D

θ

HEATSINK

θ

JC

+

()

×

()

+

=