3 dc electrical specifications, 3 dc electrical specifications -3, The average chip-junction temperature (t – Motorola ColdFire MCF5281 User Manual
Page 687: Where: t, Ambient temperature, ×c q, Watts - chip internal power p, And t, If p, Is neglected) is, Solving equations 1 and 2 for k gives
Electrical Characteristics
Freescale Semiconductor
33-3
33.3
DC Electrical Specifications
5
Thermal characterization parameter indicating the temperature difference between package top and the junction
temperature per JEDEC JESD51-2. When Greek letters are not available, the thermal characterization parameter is
written as Psi-JT.
The average chip-junction temperature (T
J
) in
°C can be obtained from:
(1)
Where:
T
A
= Ambient Temperature, ×C
Q
JMA
= Package Thermal Resistance, Junction-to-Ambient, ×C/W
P
D
= P
INT
+ P
I/O
P
INT
= I
DD
× V
DD
, Watts - Chip Internal Power
P
I/O
= Power Dissipation on Input and Output Pins — User Determined
For most applications P
I/O
< P
INT
and can be neglected. An approximate relationship
between P
D
and T
J
(if P
I/O
is neglected) is:
(2)
Solving equations 1 and 2 for K gives:
K = P
D
×
(T
A
+ 273 × C) + Q
JMA
×
P
D
2
(3)
where K is a constant pertaining to the particular part. K can be determined from equation
(3) by measuring P
D
(at equilibrium) for a known T
A
. Using this value of K, the values of
P
D
and T
J
can be obtained by solving equations (1) and (2) iteratively for any value of T
A
.
Table 33-3. DC Electrical Specifications
1
(V
SS
= V
SSPLL
= V
SSF
= V
SSA
= 0 V
DC
)
Characteristic
Symbol
Min
Max
Unit
Input High Voltage
V
IH
0.7 x V
DD
5.25
V
Input Low Voltage
V
IL
V
SS
– 0.3 0.35 x V
DD
V
Input Hysteresis
V
HYS
0.06 x
V
DD
—
mV
Input Leakage Current
V
in
= V
DD
or V
SS
, Input-only pins
I
in
-1.0
1.0
μ
A
High Impedance (Off-State) Leakage Current
V
in
= V
DD
or V
SS
, All input/output and output pins
I
OZ
-1.0
1.0
μ
A
Output High Voltage (All input/output and all output pins)
I
OH
= –5.0 mA
V
OH
V
DD
- 0.5
__
V
Output Low Voltage (All input/output and all output pins)
I
OL
= 5.0mA
V
OL
__
0.5
V
Weak Internal Pull Up Device Current, tested at V
IL
Max.
I
APU
-10
-130
μ
A
Input Capacitance
2
All input-only pins
All input/output (three-state) pins
C
in
—
—
7
7
pF
T
J
T
A
P
D
Θ
JMA
×
(
)
+
=
P
D
K
T
J
273
°C
+
(
)
÷
=
MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3