STM32F102XB datasheet(72/76 Pages) STMICROELECTRONICS

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Package characteristics

STM32F102x8, STM32F102xB

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Doc ID 15056 Rev 4

6.3.1

Evaluating the maximum junction temperature for an application

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

information scheme shown in Table 54: Ordering information scheme.

Each temperature range suffix corresponds to a specific guaranteed ambient temperature at

maximum dissipation and, to a specific maximum junction temperature. Here, only

temperature range 6 is available (–40 to 85 °C).

The following example shows how to calculate the temperature range needed for a given

application, making it possible to check whether the required temperature range is

compatible with the STM32F102xx junction temperature range.

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 8 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 + 8 × 20 mA × 1.3 V = 272 mW

This gives: PINTmax = 175 mW and PIOmax = 272 mW

PDmax = 175 + 272 = 447 mW

Thus: PDmax = 447 mW

Using the values obtained in Table 53 TJmax is calculated as follows:

–

For LQFP64, 45 °C/W

TJmax = 82 °C + (45 °C/W × 447 mW) = 82 °C + 20.1 °C = 102.1 °C

This is within the junction temperature range of the STM32F102xx (–40 < TJ < 105 °C).

Figure 40.

LQFP64 PD max vs. TA

100

200

300

400

500

600

700

105

115

TA (°C)

Suffix 6

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