MC9RS08KA1 FREESCALE [Freescale Semiconductor, Inc], MC9RS08KA1 Datasheet - Page 108

• Manufacturer Part Number: MC9RS08KA1
• Description: RS08 Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Appendix A Electrical Characteristics
A.3
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 voltage regulator circuits and it is user-determined rather than being controlled by the
MCU design. In order to take P
actual pin voltage and V
unusually high pin current (heavy loads), the difference between pin voltage and V
small.
The average chip-junction temperature (T
where:
For most applications, P
(if P
108
I/O
is neglected) is:
1
2
3
4
Thermal Characteristics
Operating temperature range (packaged)
Maximum junction temperature
Thermal resistance
6-pin DFN
8-pin PDIP
8-pin SOIC
T
P
P
P
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
JA
A
D
int
I/O
= Ambient temperature, C
= 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
SS
DD
Rating
1,2,3,4
or V
, Watts — chip internal power
P
I/O
DD
int
into account in power calculations, determine the difference between
and can be neglected. An approximate relationship between P
MC9RS08KA2 Series Data Sheet, Rev. 3
and multiply by the pin current for each I/O pin. Except in cases of
Table A-2. Thermal Characteristics
T
J
J
= T
) in C can be obtained from:
A
2s2p
2s2p
2s2p
+ (P
1s
1s
1s
D
Symbol
T
JMAX
JA
T
JA
A
)
–40 to 85
T
Value
L
105
225
115
160
53
74
98
to T
H
SS
Freescale Semiconductor
or V
Unit
C/W
DD
C
C
will be very
D
Eqn. A-1
and T
J