BCM43236BKMLG Datasheet, PDF (40/43 Pages) Cypress Semiconductor – 2.4 GHz/5 GHz IEEE802.11n MAC/PHY/Radio Chip

BCM43236/BCM43236B Preliminary Data Sheet
Thermal Information
Section 8: Thermal Information
Airflow
θ_JA (°C/W)
θ_JB (°C/W)
θ_JC (°C/W)
Ψ_JT (°C/W)
0 fpm,
0 mps
20.79
3.95
12.44
3.51
Table 20: 88-Pin QFN Thermal Characteristics
100 fpm,
0.508 mps
17.55
–
–
3.50
200 fpm,
1.016 mps
16.24
–
–
3.55
400 fpm,
2.032 mps
15.00
–
–
3.59
600 fpm,
3.048 mps
14.34
–
–
3.61
Note:
• In the thermal characterizations that were done on BCM43236/BCM43236B chips using a 4-layer
board, the temperature at 1 mm above the shield must be no higher than 65°C in order to keep
the junction temperature (T_J) from exceeding 125°C.
• The BCM43236/BCM43236B chips are designed and rated for operation at a maximum T_J of
125°C.
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
Package thermal characterization measurements: The temperature above the shield is 65°C for the T_J to be less
than 125°C with a P_out of 15 dBm.
BROADCOM ®
September 16, 2013 • 43236_43236B-DS103-R
Page 39