STM32L4S5AI datasheet(270/275 Pages) STMICROELECTRONICS

270 / 275 page

Package information

STM32L4S5xx, STM32L4S7xx and STM32L4S9xx

270/275

DocID030322 Rev 2

7.7

Thermal characteristics

The maximum chip-junction temperature, TJ max, in degrees Celsius, may be calculated

using the following equation:

TJ max = TA max + (PD max x ΘJA)

Where:

•

TA max is the maximum ambient temperature in °C,

•

ΘJA is the package junction-to-ambient thermal resistance, in °C/W,

•

PD max is the sum of PINT max and PI/O max (PD max = PINT max + PI/Omax),

•

PINT max is the product of IDD and VDD, expressed in Watts. This is the maximum chip

internal power.

PI/O max represents the maximum power dissipation on output pins where:

PI/O max = Σ (VOL × IOL) + Σ ((VDDIOx – VOH) × IOH),

taking into account the actual VOL / IOL and VOH / IOH of the I/Os at low and high level in the

application.

7.7.1

Reference document

JESD51-2 Integrated Circuits Thermal Test Method Environment Conditions - Natural

Convection (Still Air). Available from www.jedec.org

7.7.2

Selecting the product temperature range

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

information scheme shown in Section 8: Ordering information.

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 STM32L4Sxxx 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.

Table 128. Package thermal characteristics

Symbol

Parameter

Value

Unit

ΘJA