Datasheet

NXP Semiconductors 55
10XS3435
10.1.4 Device on thermal test board
R
θJA
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 24. Steady state thermal resistance in dependence on heat spreading area;
1s JEDEC thermal test board with spreading areas
Material: Single layer printed circuit board
FR4, 1.6 mm thickness
Cu traces, 0.07 mm thickness
Cu buried traces thickness 0.035mm
Outline: 76.2 mm x 114.3 mm board area, including edge connector for thermal testing,
74 mm x 74 mm buried layers area
Area A: Cu heat-spreading areas on board surface
Ambient Conditions: Natural convection, still air
Table 27. Thermal resistance performance
Thermal Resistance
Area A
(mm
2
)
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
θ
JAmn
0 47.77 36.90 54.35
150 42.90 33.21 51.07
300 40.95 31.78 49.63
450 39.85 30.89 48.61
600 38.96 30.21 47.90
25.00
30.00
35.00
40.00
45.00
50.00
55.00
60.00
65.00
0 100 200 300 400 500 600
Heat spreading area [sqmm]
Thermal resistance [K/W]
RJA11 RJA12=RJA21 RJA22