MC68HC705C8ACS

Manufacturer Part NumberMC68HC705C8ACS
DescriptionHCMOS 8-bit microcontroller unit
ManufacturerMotorola
MC68HC705C8ACS datasheet

CaseDIP-40L
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Electrical Specifications

13.6 Power Considerations
The average chip junction temperature, T
Where:
T
P
P
P
For most applications, P
Ignoring P
Solving equations (1) and (2) for K gives:
where K is a constant pertaining to the particular part. K can be
determined from equation (3) by measuring P
known T
by solving equations (1) and (2) iteratively for any value of T
Technical Data
174
T
= T
+ (P
J
A
D
= ambient temperature in C
A
= package thermal resistance, junction to ambient in C/W
JA
= P
+ P
D
INT
I/O
= I
V
= chip internal power dissipation
INT
CC
CC
= power dissipation on input and output pins (user-determined)
I/O
< P
I/O
INT
, the relationship between P
I/O
K
P
=
D
T
+ 273 C
J
= P
x (T
+ 273 C) +
D
A
. Using this value of K, the values of P
A

Electrical Specifications

, in C can be obtained from:
J
x
)
JA
and can be neglected.
and T
is approximately:
D
J
2
x (P
)
JA
D
(at equilibrium) for a
D
and T
can be obtained
D
J
.
A
MC68HC705C8A — Rev. 3
MOTOROLA
(1)
(2)
(3)