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
(PDmax = 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 pins
Where: 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 58: Thermal characteristics
UnitValueParameter
(1)
Symbol
°C/W84Thermal resistance junction-ambient
TSSOP20 - 4.4 mm
Θ
JA
91Thermal resistance junction-ambient
SO20W (300 mils)
Θ
JA
90Thermal resistance junction-ambient
UFQFPN20 - 3 x 3 mm
Θ
JA
60Thermal resistance junction-ambient
LQFP32 - 7 x 7 mm
Θ
JA
38Thermal resistance junction-ambient
UFQFPN32 - 5 x 5 mm
Θ
JA
60Thermal resistance junction-ambient
SDIP32 - 400 mils
Θ
JA
(1)
Thermal resistances are based on JEDEC JESD51-2 with 4-layer PCB in a natural
convection environment.
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STM8S103K3 STM8S103F3 STM8S103F2Thermal characteristics