MC9S08AW8A FREESCALE [Freescale Semiconductor, Inc], MC9S08AW8A Datasheet - Page 305

• Manufacturer Part Number: MC9S08AW8A
• Description: 8-Bit HCS08 Central Processor Unit (CPU)
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

A.4
This section provides information about operating temperature range, power dissipation, and package
thermal resistance. Power dissipation on I/O pins is usually small compared to the power dissipation in
on-chip logic and it is user-determined rather than being controlled by the MCU design. In order to take
P
V
loads), the difference between pin voltage and V
The average chip-junction temperature (T
where:
For most applications, P
(if P
Solving equations 1 and 2 for K gives:
Freescale Semiconductor
I/O
DD
I/O
into account in power calculations, determine the difference between actual pin voltage and V
and multiply by the pin current for each I/O pin. Except in cases of unusually high pin current (heavy
is neglected) is:
Thermal Characteristics
T
θ
P
P
P
JA
1
2
3
4
A
D
int
I/O
Operating temperature range (packaged)
Thermal resistance
48-pin QFN
44-pin LQFP
32-pin LQFP
= Ambient temperature, °C
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.
Junction to Ambient Natural Convection
1s - Single Layer Board, one signal layer
2s2p - Four Layer Board, 2 signal and 2 power layers
= P
= Package thermal resistance, junction-to-ambient, °C/W
= I
= Power dissipation on input and output pins — user determined
int
DD
+ P
× V
I/O
I/O
DD
<< P
, Watts — chip internal power
1,2,3,4
int
Rating
and can be neglected. An approximate relationship between P
MC9S08AC16 Series Data Sheet, Rev. 6
Table A-3. Thermal Characteristics
P
T
D
J
= K ÷ (T
J
= T
) in °C can be obtained from:
A
+ (P
SS
J
D
+ 273°C)
or V
× θ
Appendix A Electrical Characteristics and Timing Specifications
JA
2s2p
2s2p
2s2p
DD
)
1s
1s
1s
will be very small.
Symbol
θ
T
JA
A
–40 to 125
T
Value
L
84
27
73
56
85
56
to T
H
°C/W
Unit
°C
D
Eqn. A-1
Eqn. A-2
and T
SS
or
305
J