Datasheet

Thermal characteristics12
The maximum chip junction temperature (T
J max
) must never exceed the values given in
Operating conditions
The maximum chip-junction temperature, T
Jmax
, in degrees Celsius, may be calculated using
the following equation:
T
Jmax
= T
Amax
+ (P
Dmax
x Θ
JA
)
Where:
•
T
Amax
is the maximum ambient temperature in °C
•
Θ
JA
is the package junction-to-ambient thermal resistance in ° C/W
•
P
Dmax
is the sum of P
INTmax
and P
I/Omax
(P
Dmax
= P
INTmax
+ P
I/Omax
)
•
P
INTmax
is the product of I
DD
andV
DD
, expressed in Watts. This is the maximum chip internal
power.
•
P
I/Omax
represents the maximum power dissipation on output pinsWhere:P
I/Omax
=Σ (V
OL
*I
OL
)
+ Σ((V
DD
-V
OH)
*I
OH
), taking into account the actual V
OL
/I
OL and
V
OH
/I
OH
of the I/Os at low
and high level in the application.
Table 57: Thermal characteristics
(1)
UnitValueParameterSymbol
°C/W57
Thermal resistance junction-ambientΘ
JA
LQFP 48 - 7 x 7 mm
°C/W54
Thermal resistance junction-ambientΘ
JA
LQFP 44 - 10 x 10 mm
°C/W60
Thermal resistance junction-ambientΘ
JA
LQFP 32 - 7 x 7 mm
°C/W38
Thermal resistance junction-ambientΘ
JA
UFQFPN 32 - 5 x 5 mm
°C/W60
Thermal resistance junction-ambientΘ
JA
SDIP 32 - 400 mils
1. Thermal resistances are based on JEDEC JESD51-2 with 4-layer PCB in a natural
convection environment.
111/124DocID14771 Rev 12
Thermal characteristicsSTM8S105xx