STM8S003K3 STM8S003F3
Thermal characteristics
11
Thermal characteristics
The maximum chip junction temperature (TJ max) must never exceed the values given in
Operating conditions.
The maximum chip-junction temperature, TJmax, in degrees Celsius, may be calculated using
the following equation:
TJmax = TAmax + (PDmax x ΘJA)
Where:
TAmax is the maximum ambient temperature in °C
•
ΘJA is the package junction-to-ambient thermal resistance in °C/W
•
PDmax is the sum of PINTmax and PI/Omax (PDmax = PINTmax + PI/Omax
)
•
PINTmax is the product of IDD andVDD, expressed in Watts. This is the maximum chip internal
power.
•
PI/Omax represents the maximum power dissipation on output pins
•
Where: PI/Omax =Σ (VOL*IOL) + Σ((VDD-VOH)*IOH), taking into account the actual VOL/IOL and
VOH/IOH of the I/Os at low and high level in the application.
Table 54: Thermal characteristics
Symbol
Parameter(1)
Value
Unit
ΘJA
ΘJA
ΘJA
Thermal resistance junction-ambient
TSSOP20 - 4.4 mm
84
°C/W
90
60
Thermal resistance junction-ambient
UFQFPN20 - 3 x 3 mm
Thermal resistance junction-ambient
LQFP32 - 7 x 7 mm
(1)Thermal resistances are based on JEDEC JESD51-2 with 4-layer PCB in a natural
convection environment.
11.1
11.2
Reference document
JESD51-2 integrated circuits thermal test method environment conditions - natural convection
(still air). Available from www.jedec.org.
Selecting the product temperature range
When ordering the microcontroller, the temperature range is specified in the order code.
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