STM32F328C8 datasheet(106/109 Pages) STMICROELECTRONICS

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Package characteristics

STM32F328C8

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7.2.2

Selecting the product temperature range

When ordering the microcontroller, the temperature range is specified in the ordering

information scheme shown in Table 68: 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 STM32F328C8 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: high-performance application

Assuming the following application conditions:

Maximum ambient temperature TAmax = 82 °C (measured according to JESD51-2),

IDDmax = 50 mA, VDD = 3.5 V, maximum 20 I/Os used at the same time in output at low

level with IOL = 8 mA, VOL= 0.4 V and maximum 2 I/Os used at the same time in output

mode at low level with IOL = 20 mA, VOL= 1.3 V

PINTmax = 50 mA × 3.5 V = 175 mW

PIOmax = 20 × 8 mA × 0.4 V + 2 × 20 mA × 1.3 V = 61.6 mW

This gives: PINTmax = 175 mW and PIOmax = 61.6 mW

PDmax = 175 + 61.6 = 236.6 mW

Thus: PDmax = 236.6 mW

Using the values obtained in Table 67 TJmax is calculated as follows:

–

For LQFP48, 55 °C/W

TJmax = 82 °C + (55 °C/W × 236.6 mW) = 82 °C + 13.01 °C = 95.01°C

This is within the range of the suffix 6 version parts (–40 < TJ < 105 °C).

In this case, parts must be ordered at least with the temperature range suffix 6 (see

Table 68: Ordering information scheme).

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