Document Number: 002-14949 Rev. *G
Page 107 of 113
PRELIMINARY
CYW43353
20. Package Information
20.1 Package Thermal Characteristics
20.2 Junction Temperature Estimation and PSI
JT
Versus THETA
JC
Package thermal characterization parameter PSI–J
T
(
JT
) yields a better estimation of actual junction temperature (T
J
) versus using
the junction-to-case thermal resistance parameter Theta–J
C
(
JC
). The reason for this is that
JC
assumes that all the power is dis-
sipated through the top surface of the package case. In actual applications, some of the power is dissipated through the bottom and
sides of the package.
JT
takes into account power dissipated through the top, bottom, and sides of the package. The equation for
calculating the device junction temperature is:
TJ = TT + P x
JT
Where:
■
T
J
= Junction temperature at steady-state condition (°C)
■
T
T
= Package case top center temperature at steady-state condition (°C)
■
P = Device power dissipation (Watts)
■
JT
= Package thermal characteristics; no airflow (°C/W)
20.3 Environmental Characteristics
For environmental characteristics data, see
Table 24, “Environmental Ratings,”
.
Table 54. Package Thermal Characteristics
1
1.
No heat sink, TA = 70°C. This is an estimate, based on a 4-layer PCB that conforms to EIA/JESD51–7 (101.6 mm × 101.6 mm × 1.6 mm) and P = specified
power maximum continuous power dissipation.
Characteristic
WLBGA
JA
(°C/W) (value in still air)
32.9
JB
(°C/W)
2.56
JC
(°C/W)
0.98
JT
(°C/W)
3.30
JB
(°C/W)
9.85
Maximum Junction Temperature T
j
(°C)
125
Maximum Power Dissipation (W)
1.119
