STM32F051C8T6 Datasheet, PDF (101/104 Pages) STMicroelectronics – Low- and medium-density advanced ARM-based 32-bit MCU with 16 to 64 Kbytes Flash, timers, ADC, DAC and comm. interfaces

Package characteristics
STM32F051x
Note:
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 - (45°C/W × 447 mW) = 105-20.115 = 84.885 °C
Suffix 7: T_Amax = T_Jmax - (45°C/W × 447 mW) = 125-20.115 = 104.885 °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.
Assuming the following application conditions:
Maximum ambient 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 72 T_Jmax is calculated as follows:
– For LQFP64, 45 °C/W
T_Jmax = 100 °C + (45 °C/W × 134 mW) = 100 °C + 6.03 °C = 106.03 °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 in order to be able to
use suffix 6 parts.
Refer to figure 38 to select the required temperature range (suffix 6 or 7) according to your
ambient temperature or power requirements.
Figure 39. LQFP64 P_D max vs. T_A
700
600
500
400
300
200
100
0
65 75 85 95 105 115 125 135
T_A (°C)
Suffix 6
Suffix 7
102/105
Doc ID 022265 Rev 3