Datasheet

Electrical Specifications
MC68HC908QB8 Data Sheet, Rev. 3
208 Freescale Semiconductor
18.3 Functional Operating Range
18.4 Thermal Characteristics
Characteristic Symbol Value Unit
Temperature
Code
Operating temperature range
T
A
(T
L
to T
H
)
– 40 to +125
– 40 to +105
– 40 to +85
°C
M
V
C
Operating voltage range V
DD
2.7 to 5.5 V —
Characteristic Symbol Value Unit
Thermal resistance
16-pin PDIP
16-pin SOIC
16-pin TSSOP
θ
JA
76
90
133
°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 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
150 °C