Datasheet

Thermal characteristics
STM8S105xx
• Maximum 8 standard I/Os used at the same time in output at low level with I
OL
= 10
mA, V
OL
= 2 V
• Maximum 4 high sink I/Os used at the same time in output at low level with I
OL
= 20
mA, V
OL
= 1.5 V
• Maximum 2 true open drain I/Os used at the same time in output at low level with I
OL
=
20 mA, V
OL
= 2 V
P
INTmax
= 15 mA x 5.5 V = 82.5 mW
P
IOmax
= (10 mA x 2 V x 8 )+(20 mA x 2 V x 2)+(20 mA x 1.5 V x 4) = 360 mW
This gives: P
INTmax
= 82.5 mW and P
IOmax
360 mW:
P
Dmax
= 82.5 mW + 360 mW
Thus: P
Dmax
= 443 mW
T
Jmax
for LQFP32 can be calculated as follows, using the thermal resistance Θ
JA
:
T
Jmax
= 82° C + (60° C/W x 443 mW) = 82°C + 27°C = 109° C
This is within the range of the suffix 3 version parts (-40 < T
J
< 131° C). In this case, parts
must be ordered at least with the temperature range suffix 3.
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