STMicroelectronics STM32F031C4, Manual

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STM32F031x4 STM32F031x6 Package information
109
7.8.2 Selecting the product temperature range
When ordering the microcontroller, the temperature range is specified in the ordering
information scheme shown in
Section 8: Part numbering .
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
Amax
= 80 °C (measured according to JESD51-2),
I
DDmax
= 50 mA, V
DD
= 3.5 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 and maximum 8 I/Os used at the same time in output
at low level with I
OL
= 20 mA, V
OL
= 1.3 V
P
INTmax =
50 mA × 3.5 V= 175 mW
P
IOmax = 20
× 8 mA × 0.4 V + 8 × 20 mA × 1.3 V = 272 mW
This gives: P
INTmax
= 175 mW and P
IOmax
= 272 mW:
P
Dmax =
175
+
272 = 447 mW
Using the values obtained in Table 68 T
Jmax
is calculated as follows:
– For LQFP48, 55 °C/W
T
Jmax
= 80 °C + (55°C/W × 447 mW) = 80 °C + 24.585 °C = 104.585 °C
This is within the range of the suffix 6 version parts (–40 < T
J
< 105 °C) see Table 18:
General operating conditions .
In this case, parts must be ordered at least with the temperature range suffix 6 (see
Section 8: Part numbering ).
Note: With this given P
Dmax we can find the TAmax allowed for a given device temperature range (order code suffix
6 or 7).
Suffix 6: T
Amax
= T
Jmax
- (55°C/W × 447 mW) = 105-24.585 = 80.415 °C
Suffix 7: T
Amax
= T
Jmax
- (55°C/W × 447 mW) = 125-24.585 = 100.415 °C
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
J
remains within the
specified range.
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微可Vicor——值得信赖的元器件供应商 http://www.vicor.top/ 021-31660491