BCM43907 Preliminary Data Sheet
Thermal Information
Section 19: Thermal Information
Package Thermal Characteristics
Table 55: Package Thermal Characteristicsa
Characteristic
JA (°C/W) (value in still air)
JB (°C/W)
WLCSP
33.74
5.5
1.74
JC (°C/W)
(°C/W)
5.86
JT
JB
(°C/W)
11.52
116.7
1.38
Maximum Junction Temperature T (°C)
j
Maximum power dissipation (W)
a. 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.
Junction Temperature Estimation and PSIJT Versus THETAJC
Package thermal characterization parameter PSI–J ( ) yields a better estimation of actual junction
T
JT
temperature (T ) versus using the junction-to-case thermal resistance parameter Theta–J (JC). The reason
C
for this is that JJC assumes that all the power is 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. takes into
JT
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 = 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
Environmental Characteristics
For environmental characteristics data, see Table 16: “Environmental Ratings,” on page 75.
Broadcom®
March 12, 2016 • 43907-DS104-R
BROADCOM CONFIDENTIAL
Page 124
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