STM32F103X4_13 Datasheet, PDF (84/90 Pages) STMicroelectronics – Low-density performance line, ARM-based 32-bit MCU with 16 or32 KB Flash, USB

Package characteristics
STM32F103x4, STM32F103x6
6.2.2
Selecting the product temperature range
When ordering the microcontroller, the temperature range is specified in the ordering
information scheme shown in Table 57: Ordering information scheme.
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 STM32F103xx 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 = 82 °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
Thus: P_Dmax = 447 mW
Using the values obtained in Table 56 T_Jmax is calculated as follows:
– For LQFP64, 45 °C/W
T_Jmax = 82 °C + (45 °C/W × 447 mW) = 82 °C + 20.115 °C = 102.115 °C
This is within the range of the suffix 6 version parts (–40 < T_J < 105 °C).
In this case, parts must be ordered at least with the temperature range suffix 6 (see
Table 57: Ordering information scheme).
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.
Assuming the following application conditions:
Maximum ambient temperature T_Amax = 115 °C (measured according to JESD51-2),
I_DDmax = 20 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
P_INTmax = 20 mA × 3.5 V= 70 mW
P_IOmax = 20 × 8 mA × 0.4 V = 64 mW
This gives: P_INTmax = 70 mW and P_IOmax = 64 mW:
P_Dmax = 70 + 64 = 134 mW
Thus: P_Dmax = 134 mW
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