mc68hc705k1 Freescale Semiconductor, Inc, mc68hc705k1 Datasheet - Page 119

• Manufacturer Part Number: mc68hc705k1
• Description: Hcmos Microcontroller Unit
• Manufacturer: Freescale Semiconductor, Inc

12.5 Thermal Characteristics
12.6 Power Considerations
MC68HC705K1 — Rev. 2.0
The average chip junction temperature, T
Where:
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
Maximum junction temperature
Thermal resistance
1. P = Plastic dual in-line package (PDIP)
2. DW = Small outline integrated circuit (SOIC)
Freescale Semiconductor, Inc.
MC68HC705K1P
MC68HC705K1DW
T
P
P
P
JA
A
D
INT
I/O
For More Information On This Product,
= ambient temperature in C
= P
= package thermal resistance, junction to ambient in C/W
= power dissipation on input and output pins (user-determined)
A
= I
. Using this value of K, the values of P
INT
I/O
CC
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, the relationship between P
Characteristic
= P
+ P
Electrical Specifications
V
D
I/O
(1)
CC
x (T
(2)
T
= chip internal power dissipation
P
J
D
A
= T
I/O
+ 273 C) +
=
A
< P
T
+ (P
J
INT
+ 273 C
D
K
and can be neglected.
x
JA
JA
)
x (P
D
J
Symbol
, in C can be obtained from:
and T
T
D
JA
J
D
)
D
2
(at equilibrium) for a
and T
J
is approximately:
Thermal Characteristics
Electrical Specifications
J
Value
can be obtained
150
100
140
Technical Data
A
.
Unit
C/W
C
(1)
(2)
(3)