XC68HC705F32 Motorola, XC68HC705F32 Datasheet - Page 156

• Manufacturer Part Number: XC68HC705F32
• Description: MICROCONTROLLER
• Manufacturer: Motorola

16
16.2
The average chip junction temperature, T
equation:
where:
Junction-to-ambient ( C/W)
An approximate relationship between P
Solving equations [1] and [2] for K gives:
where K is a constant for a particular part. K can be determined by measuring P
for a known T
by solving the above equations. The package thermal characteristics are shown in
MOTOROLA
16-2
A
Thermal characteristics and power considerations
. Using this value of K, the values of P
Thermal resistance
— 100-pin QFP package
— 80-pin QFP package
Table 16-2 Package thermal characteristics
P
P
P
INT
T
I/O
D
A
Characteristics
ELECTRICAL SPECIFICATIONS
= Ambient Temperature ( C)
= P
= Internal Chip Power = I
= Power Dissipation on Input and Output pins (User determined)
K
=
INT
P
T
+ P
D
J
D
P
J
=
and T
, in degrees Celsius can be obtained from the following
I/O
D
T
T
A
=
A
(W)
JA
+
+
J
--------------------- -
T
= Package Thermal Resistance,
273
(if P
J
P
+
K
D
Symbol Value
273
D
I/O
+
and T
JA
JA
is neglected) is:
DD
JA
• V
J
P
55
can be obtained for any value of T
D
DD
2
(W)
Unit
C/W
D
MC68HC05F32
(at equilibrium)
Table
16-2.
A
TPG