Freescale Semiconductor FlexRay MFR4310 - Page 242

Electrical Characteristics
MFR4310 Reference Manual, Rev. 2
242 Freescale Semiconductor
The total power dissipation can be calculated from:
Eqn. A-2
P
INT
= Chip Internal Power Dissipation [W]
Two cases with internal voltage regulator enabled and disabled must be considered:
1. Internal Voltage Regulator disabled
Eqn. A-3
Eqn. A-4
P
IO
is the sum of all output currents on I/O ports associated with VDDX and VDDR.
For R
DSON
is valid:
Eqn. A-5
respectively
Eqn. A-6
2. Internal voltage regulator enabled
Eqn. A-7
I
DDR
is the current shown in Table A-8 and not the overall current flowing into VDDR, which
additionally contains the current flowing into the external loads with output high.
Eqn. A-8
P
IO
is the sum of all output currents on I/O ports associated with VDDX and VDDR.
P
D
P
INT
P
IO
+=
P
INT
I
DD
V
DD
⋅ I
DDOSC
V
DDOSC
⋅ I
DDA
V
DDA
⋅++=
P
IO
R
DSON
I
IO
i
2
⋅
i
∑
=
R
DSON
V
OL
I
OL
----------
; for outputs driven low=
R
DSON
V
DD5
V
OH
–
I
OH
------------------------------
; for outputs driven high=
P
INT
I
DDR
V
DDR
⋅ I
DDA
V
DDA
⋅+=
P
IO
R
DSON
I
IO
i
2
⋅
i
∑
=