MC9S12GRMV1 Datasheet, PDF (1195/1292 Pages) Freescale Semiconductor, Inc – MC9S12G Family Reference Manual and Data Sheet

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}
P_IO is the sum of all output currents on I/O ports associated with V_DDX, whereby
RDSON = ^{V--I--O-O----L-L--;for} outputs driven low
RDSON = ^{V-----D----D-----3-I--O5-----H–}-----V----O-----H---;for outputs driven high
PINT = IDDR ⋅ VDDR + IDDA ⋅ VDDA
Freescale Semiconductor
MC9S12G Family Reference Manual, Rev.1.23
1197