STM32F302XD Datasheet, PDF (164/168 Pages) STMicroelectronics – CRC calculation unit

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STM32F302xD STM32F302xE
Note:
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 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
Using the values obtained in Table 99 T_Jmax is calculated as follows:
– For LQFP100, 42 °C/W
T_Jmax = 82 °C + (42 °C/W × 447 mW) = 82 °C + 18.774 °C = 100.774 °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
Section 8: Part numbering).
With this given P_Dmax we can find the T_Amax allowed for a given device temperature range
(order code suffix 6 or 7).
Suffix 6: T_Amax = T_Jmax - (42°C/W × 447 mW) = 105-18.774 = 86.226 °C
Suffix 7: T_Amax = T_Jmax - (42°C/W × 447 mW) = 125-18.774 = 106.226 °C
Example 2: High-temperature application
Using the same rules, it is possible to address applications that run at high temperature with
a low dissipation, as long as junction temperature T_J remains within the specified range.
Assuming the following application conditions:
Maximum temperature T_Amax = 100 °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
Using the values obtained in Table 99 T_Jmax is calculated as follows:
– For LQFP100, 42 °C/W
T_Jmax = 100 °C + (42 °C/W × 134 mW) = 100 °C + 5.628 °C = 105.628 °C
This is above 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 7 (see
Section 8: Part numbering) unless we reduce the power dissipation to be able to use suffix 6
parts.
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