Selecting The Product Temperature Range - STMicroelectronics STM32F031F4 Manual

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STM32F031x4 STM32F031x6
7.8.2

Selecting the product temperature range

When ordering the microcontroller, the temperature range is specified in the ordering
information scheme shown in
Each temperature range suffix corresponds to a specific guaranteed ambient temperature at
maximum dissipation and, to a specific maximum junction temperature.
As applications do not commonly use the STM32F031x4/x6 at maximum dissipation, it is
useful to calculate the exact power consumption and junction temperature to determine
which temperature range will be best suited to the application.
The following examples show how to calculate the temperature range needed for a given
application.
Example 1: High-performance application
Assuming the following application conditions:
Maximum ambient temperature T
I
DDmax
level with I
at low level with I
P
INTmax =
P
IOmax = 20
This gives: P
P
Dmax =
Using the values obtained in
–
T
Jmax
This is within the range of the suffix 6 version parts (–40 < T
General operating
In this case, parts must be ordered at least with the temperature range suffix 6 (see
Section 8: Part
Note: With this given P
6 or 7).
Suffix 6: T
Suffix 7: T
Example 2: High-temperature application
Using the same rules, it is possible to address applications that run at high ambient
temperatures with a low dissipation, as long as junction temperature T
specified range.
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Section 8: Part
= 50 mA, V = 3.5 V, maximum 20 I/Os used at the same time in output at low
DD
= 8 mA, V = 0.4 V and maximum 8 I/Os used at the same time in output
OL OL
= 20 mA, V
OL
50 mA × 3.5 V= 175 mW
× 8 mA × 0.4 V + 8 × 20 mA × 1.3 V = 272 mW
= 175 mW and P
INTmax
175 272 = 447 mW
+
Table 68
For LQFP48, 55 °C/W
= 80 °C + (55°C/W × 447 mW) = 80 °C + 24.585 °C = 104.585 °C
conditions.
numbering).
Dmax we can find the TAmax allowed for a given device temperature range (order code suffix
= T - (55°C/W × 447 mW) = 105-24.585 = 80.415 °C
Amax Jmax
= T - (55°C/W × 447 mW) = 125-24.585 = 100.415 °C
Amax Jmax
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numbering.
= 80 °C (measured according to JESD51-2),
Amax
= 1.3 V
OL
= 272 mW:
IOmax
T is calculated as follows:
Jmax
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Package information
< 105 °C) see Table 18:
J
remains within the
J
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