MC9S12XEP100 Datasheet, PDF (924/1036 Pages) Freescale Semiconductor, Inc – Microcontrollers

Appendix A Electrical Characteristics
A.1.8 Power Dissipation and Thermal Characteristics
Power dissipation and thermal characteristics are closely related. The user must assure that the maximum
operating junction temperature is not exceeded. The average chip-junction temperature (T_J) in °C can be
obtained from:
TJ = TA + (PD • Θ_JA)
TJ = Junction Temperature, [°C ]
TA = Ambient Temperature, [°C ]
PD = Total Chip Power Dissipation, [W]
Θ_JA = Package Thermal Resistance, [°C/W]
The total power dissipation can be calculated from:
PD = PINT + PIO
PINT = Chip Internal Power Dissipation, [W]
∑ ^{PIO =} _i ^{RDSON ⋅ IIOi2}
MC9S12XE-Family Reference Manual , Rev. 1.07
924
Freescale Semiconductor