Datasheet

Electrical Characteristics
MC68HC812A4 Data Sheet, Rev. 7
222 Freescale Semiconductor
18.2 Functional Operating Range
18.3 Thermal Characteristics
Rating Symbol Value Unit
Operating temperature range
(1)
MC68HC812A4PV8
MC68HC812A4CPV8
1. For additional information, refer to the technical supplement document for 3.3 volt specifications (MC68C812A4) . This
supplement can be found at http://freescale.com
T
A
T
L
to T
H
0 to +70
−40 to +85
°C
Operating voltage range
V
DD
5.0 ± 10% V
Characteristic Symbol Value Unit
Average junction temperature
T
J
T
A
+ (P
D
× Θ
JA
)
°C
Ambient temperature
T
A
User-determined °C
Package thermal resistance (junction-to-ambient)
112-pin thin quad flat pack (TQFP)
Θ
JA
39 °C/W
Total power dissipation
(1)
1. This is an approximate value, neglecting P
I/O
.
P
D
P
INT
+ P
I/O
or
W
Device internal power dissipation
P
INT
I
DD
× V
DD
W
I/O pin power dissipation
(2)
2. For most applications, P
I/O
« P
INT
and can be neglected.
P
I/O
User-determined W
A constant
(3)
3. K is a constant pertaining to the device. Solve for K with a known T
A
and a measured P
D
(at equilibrium). Use this value
of K to solve for P
D
and T
J
iteratively for any value of T
A
.
K
P
D
× (T
A
+ 273°C) +
Θ
JA
× P
D
2
W/°C
K
T
J
273°C+
-------------------------- -