mc9s08mm128 Freescale Semiconductor, Inc, mc9s08mm128 Datasheet - Page 15

• Manufacturer Part Number: mc9s08mm128
• Description: S08mm Flexis
• Manufacturer: Freescale Semiconductor, Inc

2.3
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 it is user-determined rather than
being controlled by the MCU design. In order to take P
actual pin voltage and V
(heavy loads), the difference between pin voltage and V
The average chip-junction temperature (T
where:
For most applications, P
is:
Freescale Semiconductor
1
2
3
4
T
θ
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
A
JA
D
int
I/O
Thermal Characteristics
#
1
2
3
4
= 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
Symbol
T
SS
I/O
I/O
JMAX
θ
θ
T
DD
JA
JA
or V
A
<< P
, Watts — chip internal power
DD
int
and multiply by the pin current for each I/O pin. Except in cases of unusually high pin current
and can be neglected. An approximate relationship between P
Operating temperature range (packaged):
Maximum junction temperature
Thermal resistance
Thermal resistance
J
) in °C can be obtained from:
Table 6. Thermal Characteristics
T
J
= T
I/O
A
1,2,3,4
1, 2, 3, 4
SS
+ (P
into account in power calculations, determine the difference between
Rating
or V
MC9S08MM128
MC9S08MM64
MC9S08MM32
MC9S08MM32A
81-pin MBGA
80-pin LQFP
64-pin LQFP
81-pin MBGA
80-pin LQFP
64-pin LQFP
D
Single-layer board — 1s
Four-layer board — 2s2p
DD
× θ
will be very small.
JA
)
Preliminary Electrical Characteristics
–40 to 105
–40 to 105
–40 to 105
–40 to 105
Value
D
135
77
55
68
47
40
49
and T
J
(if P
I/O
°C/W
°C/W
Unit
°C
°C
is neglected)
Eqn. 1
15