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19. Thermal Information
19.1 Package Thermal Characteristics
Table 32. Package Thermal Characteristics
(°C/W) (value in still air)
JA
(°C/W)
JB
(°C/W)
JC
(°C/W)
JT
(°C/W)
JB
Maximum Junction Temperature T
Maximum power dissipation (W)
1. No heat sink, TA = 70°C. This is an estimate based on a 4-layer PCB that conforms to EIA/JESD51–7. Air velocity is 0 m/s.
19.2 Junction Temperature Estimation and PSI
Package thermal characterization parameter PSI–J
the junction-to-case thermal resistance parameter Theta–J
dissipated 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.
for calculating the device junction temperature is:
TJ = TT + P x YJT
Where:
T
= Junction temperature at steady-state condition (°C)
■
J
T
= Package case top center temperature at steady-state condition (°C)
■
T
P = Device power dissipation (Watts)
■
= Package thermal characteristics; no airflow (°C/W)
■
JT
19.3 Environmental Characteristics
For environmental characteristics data, see
Document Number: 002-14826 Rev. *G
PRELIMINARY
1
Characteristic
(°C)
j
T
takes into account power dissipated through the top, bottom, and sides of the package. The equation
JT
Table 14, "Environmental
Versus THETA
JT
JC
(
) yields a better estimation of actual junction temperature (T
JT
(
). The reason for this is that
C
JC
Ratings,".
WLBGA
31.72
3.95
2.16
4.3
9.28
113.9
1.38
assumes that all the power is
JC
CYW43903
) versus using
J
Page 61 of 65
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