STWBC datasheet(32/36 Pages) STMICROELECTRONICS

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Thermal characteristics

STWBC

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DocID027322 Rev 3

Thermal characteristics

The STWBC functionality cannot be guaranteed when the device operating exceeds the

maximum chip junction temperature (TJmax).

TJmax, in °C, may be calculated using equation:

TJmax = TAmax + (PDmax x JA)

where:

TAmax is the maximum ambient temperature in °C

JA is the package junction to ambient thermal resistance in °C/W

PDmax is the sum of PINTmax and PI/Omax (PDmax = PINTmax + PI/Omax)

PINTmax is the product of IDD and VDD, expressed in watts. This is the maximum chip internal

power.

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

PI/Omax =  (VOL * IOL) + [(VDD - VOH) * IOH],

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

Table 20. Package thermal characteristics

Symbol

Parameter

Value

Unit

JA

VFQFPN32 - thermal resistance junction to ambient(1)

1. Thermal resistance is based on JEDEC JESD51-2 with 4-layer PCB in a natural convection environment.

°C/W

STWBC 数据表(PDF) 32 Page - STMicroelectronics