Datasheet

Electrical Specifications
Functional Operating Range
MC68HC908JB8•MC68HC08JB8•MC68HC08JT8 — Rev. 2.3 Technical Data
Freescale Semiconductor Electrical Specifications 255
18.4 Functional Operating Range
18.5 Thermal Characteristics
Characteristic Symbol Value Unit
Operating temperature range
T
A
0 to 70 °C
Operating voltage range
V
DD
4.0 to 5.5 V
Characteristic Symbol Value Unit
Thermal Resistance
QFP (44 pins)
SOIC (28 pins)
SOIC (20 pins)
PDIP (20 pins)
θ
JA
95
70
70
70
°C/W
I/O pin power dissipation
P
I/O
User determined W
Power dissipation
(1)
NOTES:
1. Power dissipation is a function of temperature.
P
D
P
D
= (I
DD
× 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
× θ
JA
W/°C
Average junction temperature
T
J
T
A
+ (P
D
× θ
JA
)
°C
Maximum junction temperature
T
JM
100 °C