Datasheet

Electrical characteristics STM8AF52/62xx, STM8AF51/61xx
88/110 Doc ID 14395 Rev 9
10.4.2 Selecting the product temperature range
When ordering the microcontroller, the temperature range is specified in the order code (see
Figure 52: Ordering information scheme(1) on page 98).
The following example shows how to calculate the temperature range needed for a given
application.
Assuming the following application conditions:
– Maximum ambient temperature T
Amax
= 82 °C (measured according to JESD51-2)
–I
DDmax
= 8 mA
–V
DD
= 5 V
– maximum 20 I/Os used at the same time in output at low-level with I
OL
= 8 mA
–V
OL
= 0.4 V
Equation 5
P
INTmax
= 8 mA x 5 V = 400 mW
Equation 6
P
IOmax
= 20 x 8 mA x 0.4 V = 64 mW
This gives:
P
INTmax
= 400 mW and P
IOmax
64 mW:
Equation 7
P
Dmax
= 400 mW + 64 mW
Thus:
P
Dmax
= 464 mW.
Using the values obtained in Table 51: Thermal characteristics on page 87 T
Jmax
is
calculated as follows:
For LQFP64 46 °C/W
Equation 8
T
jmax
= 82 °C + (46 °C/W x 464 mW) = 82 °C + 21 °C = 103 ° C
This is within the range of the suffix B version parts (-40 °C < T
j
< 105 ° C).
Parts must be ordered at least with the temperature range suffix B.