44

NXP Semiconductors

33982

ADDITIONAL DOCUMENTATION

RJAis the thermal resistance between die junction and ambient air. This device is a dual die package. Index m indicates the die that is

heated. Index n refers to the number of the die where the junction temperature is sensed.

Figure 15. Device on thermal test board RJA

Table 21. Device on thermal test board

Material:

Single layer printed circuit board

FR4, 1.6 mm thickness

Cu traces, 0.07 mm thickness

Outline:

80 mm x 100 mm board area, including edge

connector for thermal testing

Area A:

Cu heat-spreading areas on board surface

Ambient Conditions:

Natural convection, still air

Table 22. Thermal resistance performance

Thermal

Resistance

Area A

(mm2)

1 = Power Chip, 2 = Logic Chip (

C/W)

m =1,

n =1

m =1, n =2

m =2, n =1

m =2,

n =2

RJAmn

055

42

74

300

41

32

66

600

39

29

65

0

10

20

30

40

50

60

70

80

Heat spreading area A [mm²]

0

300

600

RJA11

RJA22

RJA12 =RJA21

x