MC9S12DT256_06 Datasheet, PDF (94/132 Pages) Freescale Semiconductor, Inc – Device User Guide V03.07

MC9S12DT256 Device User Guide — V03.07
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]
Two cases with internal voltage regulator enabled and disabled must be considered:
1. Internal Voltage Regulator disabled
PINT = IDD ⋅ VDD + IDDPLL ⋅ VDDPLL + IDDA ⋅ VDDA
∑ ^{PIO =} _i ^{RDSON ⋅ IIOi2}
P_IO is the sum of all output currents on I/O ports associated with VDDX and VDDR.
For R_DSON is valid:
RDSON = ^{V--I--O-O----L-L-} ;for outputs driven low
respectively
RDSON = -V----D----D----I-5-O----^–-H---V-----O-----H-- ;for outputs driven high
2. Internal voltage regulator enabled
PINT = IDDR ⋅ VDDR + IDDA ⋅ VDDA
I_DDR is the current shown in Table A-7 and not the overall current flowing into VDDR, which
additionally contains the current flowing into the external loads with output high.
∑ ^{PIO =} _i ^{RDSON ⋅ IIOi2}
P_IO is the sum of all output currents on I/O ports associated with VDDX and VDDR.
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