MCF52235 Datasheet, PDF (30/50 Pages) Freescale Semiconductor, Inc – ColdFire Microcontroller

Preliminary Electrical Characteristics
Table 20. Thermal Characteristics (continued)
Characteristic
Symbol
Package¹
Value
Unit
Junction to ambient (@200 ft/min)
θ_JMA
80-pin LQFP, four-layer board
112-pin LQFP, four-layer board
30.0
°C / W
29.0
Junction to board
121 MAPBGA, four-layer board
80-pin LQFP, one-layer board¹
112-pin LQFP, one-layer board¹
121 MAPBGA, one-layer board¹
θ_JB 80-pin LQFP
112-pin LQFP
28
39.0¹
35.0¹
46¹
22.0⁴
23.0
°C / W
Junction to case
121 MAPBGA, four-layer board
θ_JC 80-pin LQFP
112-pin LQFP
18
6.0⁵
°C / W
6.0
121 MAPBGA
10
Junction to top of package, natural convection
Ψ_jt
80-pin LQFP
112-pin LQFP
2.0⁶
°C / W
2.0⁶
121 MAPBGA
2.0⁶
Maximum operating junction temperature
T_j
All
130
o_C
1 _{The use of this device in one- or two-layer board designs is not recommended due to the limited thermal conductance}
provided by those boards.
2 _{θJMA and Ψjt parameters are simulated in conformance with EIA/JESD Standard 51-2 for natural convection. Freescale}
recommends the use of θ_JMA and power dissipation specifications in the system design to prevent device junction
temperatures from exceeding the rated specification. System designers should be aware that device junction temperatures
can be significantly influenced by board layout and surrounding devices. Conformance to the device junction temperature
specification can be verified by physical measurement in the customer’s system using the Ψ_jt parameter, the device power
dissipation, and the method described in EIA/JESD Standard 51-2.
3 _{Per JEDEC JESD51-6 with the board horizontal.}
4 _{Thermal resistance between the die and the printed circuit board in conformance with JEDEC JESD51-8. Board}
temperature is measured on the top surface of the board near the package.
5 _{Thermal resistance between the die and the case top surface as measured by the cold plate method (MIL SPEC-883}
Method 1012.1).
6 _{Thermal characterization parameter indicating the temperature difference between package top and the junction}
temperature per JEDEC JESD51-2. When Greek letters are not available, the thermal characterization parameter is written
in conformance with Psi-JT.
MCF52235 ColdFire Microcontroller, Rev. 3
30
Freescale Semiconductor