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DC Electrical Characteristics
This device contains circuitry protecting against damage from high-static voltage or
electrical fields. However, it is advised that precautions be taken to avoid application of any
voltages higher than the maximum-rated voltages to this high-impedance circuit. Reliability
of operation is enhanced if unused inputs are tied to an appropriate logic voltage level (either
GND or V
).
CC
22.2 THERMAL CHARACTERISTICS
CHARACTERISTIC
Thermal Resistance for BGA
22.3 POWER CONSIDERATIONS
The average chip-junction temperature
T
= T
+ (P
•
J
A
D
where
T
=
Ambient Temperature
A
q
=
Package Thermal Resistance
JA
P
=
P
D
INT
P
=
I
x V
INT
DD
P
=
Power Dissipation on Input and Output Pins—User Determined
I/O
For most applications P
I/O
approximate relationship between P
K ∏ (T
P
=
D
Solving equations (1) and (2) for K gives
•
K =
P
D
where K is a constant pertaining to the particular part. K can be determined from equation
(3) by measuring P
(at equilibrium) for a known T
D
and T
can be obtained by solving equations (1) and (2) iteratively for any value of T
J
22-2
SYMBOL
θ
in ° C can be obtained from
T
,
,
J
q
)
(1)
JA
∞ C
,
+ P
I/O
Watts—Chip Internal Power
,
DD
< 0.3
P
and can be neglected. If P
•
INT
and T
is:
D
J
+ 273 ∞ C)
(2)
J
2
+ 273 ∞ C) + q
(T
• P
A
JA
D
MPC823e REFERENCE MANUAL
VALUE
UNIT
° C/W
~30
JA
∞ C/W
Junction to Ambient
,
,
is neglected
I/O
(3)
. Using this value of K
,
A
an
,
the values of P
D
.
A
MOTOROLA
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