BCM4319XKUBGT Datasheet, PDF (81/84 Pages) Cypress Semiconductor – Single-Chip IEEE 802.11™ a/b/g/n MAC/Baseband/ Radio with Integrated SDIO and USB Interfaces

BCM4319 Preliminary Data Sheet
Package Information
Section 16: Package Information
Package Thermal Characteristics
Table 31: 138-Ball WLBGA Package Thermal Characteristics^a
Airflow
0 fpm,
0 mps
100 fpm,
0.508 mps
200 fpm,
0.508 mps
400 fpm,
0.508 mps
θ_JA (°C/W)
θ_JB (°C/W)
θ_JC (°C/W)
ψ_JT (°C/W)
29.79
1.06
0.09
0.03
27.34
–
–
0.03
26.59
–
–
0.03
25.79
–
–
0.03
a. No heat sink, TA = 85ºC. This is an estimate based on 2-layer PCB and P = 1.1W.
600 fpm,
0.508 mps
25.29
–
–
0.03
Junction Temperature Estimation and PSI_JT VERSUS THETA_JC
Package thermal characterization parameter PSI-JT (Ψ_JT) yields a better estimation of actual junction
temperature (T_J) versus using the junction-to-case thermal resistance parameter Theta-JC (Θ_JC). The reason
for this is Θ_JC 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. Ψ_JT takes into
account power dissipated through the top, bottom, and sides of the package.
The equation for calculating the device junction temperature is as follows:
T_J = T_T + P × Ψ_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)
• Ψ_JT = Package thermal characteristics; no airflow (°C/W)
Broadcom^®
April 2, 2014 • 4319-DS05-R
Single-Chip IEEE 802.11™ a/b/g/n MAC/Baseband/Radio
Page 80