Appendix A MCU Electrical Specifications
MC9S12ZVM Family Reference Manual Rev. 1.3
748
Freescale Semiconductor
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:
The total power dissipation P
D
can be calculated from the equation below. Table A-6 below lists the power
dissipation components.
gives an overview of the supply currents.
Table A-7. Power Dissipation Components
Power Component
Description
P
VSUP
= V
SUP
I
SUP
Internal Power through VSUP pin
P
BCTL
= V
BCTL
I
BCTL
Internal Power through BCTL pin
P
INT
= V
DDX
I
VDDX
+ V
DDA
I
VDDA
Internal Power through VDDX/A pins.
P
GPIO
= V
I/O
I
I/O
Power dissipation of external load driven by GPIO Port.
Assuming the load is connected between GPIO and
ground. This power component is included in P
INT
and
is subtracted from overall MCU power dissipation P
D
P
LIN
= V
LIN
I
LIN
Power dissipation of LINPHY
P
GDU
(1)
= (-V
VLS_OUT
I
VLS_OUT
) + (V
VBS
I
VBS
) +
(V
VCP
I
VCP
) + (V
VLSn
I
VLSn
)
1. No switching. GDU power consumption is very load dependent.
Power dissipation of FET-Predriver without the outputs
switching
T
J
T
A
P
D
Θ
JA
•
(
)
+
=
T
J
Junction Temperature, [
°
C
]
=
T
A
Ambient Temperature, [
°
C
]
=
P
D
Total Chip Power Dissipation, [W]
=
Θ
JA
Package Thermal Resistance, [
°
C/W]
=
P
D
= P
VSUP
+ P
BCTL
+ P
INT
- P
GPIO
+ P
LIN
- P
EVDD1
+ P
GDU
