Microcontrollers Data Sheet
Electrical Specifications
MC68HC908MR32 • MC68HC908MR16 Data Sheet, Rev. 6.1
266 Freescale Semiconductor
19.3 Functional Operating Range
19.4 Thermal Characteristics
Characteristic Symbol Value Unit
Operating temperature range
(1)
MC68HC908MR24CFU
MC68HC908MR24VFU
1. See Freescale representative for temperature availability.
C = Extended temperature range (–40°C to +85°C)
V = Automotive temperature range (–40°C to +105°C)
T
A
–40 to 85
–40 to 105
°C
Operating voltage range
V
DD
5.0 ± 10% V
Characteristic Symbol Value Unit
Thermal resistance,
64-pin QFP
θ
JA
76 °C/W
I/O pin power dissipation
P
I/O
User determined W
Power dissipation
(1)
1. Power dissipation is a function of temperature.
P
D
P
D
= (I
DD
x V
DD
) + P
I/O
=
K/(T
J
+ 273°C)
W
Constant
(2)
2. K is a constant unique to the device. K can be determined for a known T
A
and measured
P
D.
With this value of K, P
D
and
T
J
can be determined for any value of T
A
.
K
P
D
x
(T
A
+ 273°C)
+ P
D
2
x
θ
JA
W/°C
Average junction temperature
T
J
T
A
+ (P
D
x
θ
JA
)
°C
Maximum junction temperature
T
JM
125 °C