CD00253742 Datasheet, PDF (115/120 Pages) STMicroelectronics – XL-density performance line ARM-based 32-bit MCU

STM32F103xF, STM32F103xG
Package characteristics
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 73: STM32F103xF and STM32F103xG 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 STM32F103xF and STM32F103xG 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 72 T_Jmax is calculated as follows:
– For LQFP100, 46 °C/W
T_Jmax = 82 °C + (46 °C/W × 447 mW) = 82 °C + 20.6 °C = 102.6 °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 73: STM32F103xF and STM32F103xG 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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