Datasheet

Appendix A Electrical Characteristics
MC9S08DZ60 Series Data Sheet, Rev. 4
Freescale Semiconductor 371
The average chip-junction temperature (T
J
) in °C can be obtained from:
T
J
= T
A
+ (P
D
×θ
JA
) Eqn. A-1
where:
T
A
= Ambient temperature, °C
θ
JA
= 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:
P
D
= K ÷ (T
J
+ 273°C) Eqn. A-2
Solving equations 1 and 2 for K gives:
K = P
D
× (T
A
+ 273°C) + θ
JA
× (P
D
)
2
Eqn. A-3
Table A-3. Thermal Characteristics
Num C Rating Symbol Value Unit
Temp.
Code
1D
Operating temperature range (packaged)
T
A
–40 to 125
–40 to 105
–40 to 85
°C
M
V
C
2T
Maximum Junction Temperature
1
1
Junction temperature is a function of die size, on-chip power dissipation, package thermal resistance, mounting site
(board) temperature, ambient temperature, air flow, power dissipation of other components on the board, and board
thermal resistance.
T
J
135 °C—
3D
Thermal resistance
2
2
Junction to Ambient Natural Convection
Single-layer board
64-pin LQFP
θ
JA
69 °C/W
48-pin LQFP
θ
JA
75 °C/W
32-pin LQFP
θ
JA
80 °C/W
Four-Layer board
64-pin LQFP
θ
JA
51 °C/W
48-pin LQFP
θ
JA
51 °C/W
32-pin LQFP
θ
JA
52 °C/W