ST72E632K2B0 Ver la hoja de datos (PDF) - STMicroelectronics

Número de pieza

componentes Descripción

Fabricante

ST72E632K2B0

LOW SPEED USB 8-BIT MCU FAMILY with up to 16K MEMORY, up to 512 BYTES RAM, 8-BIT ADC, WDG, TIMER, SCI & I2C

STMicroelectronics 

ST7263

7.2 THERMAL CHARACTERISTICS

The average chip-junction temperature, TJ, in de-

grees Celsius, may be calculated using the follow-

ing equation:

An approximate relationship between PD and TJ

(if PI/O is neglected) is given by:

TJ = TA + (PD x θJA) (1)*

Where:

– TA is the Ambient Temperature in °C,

– θJA is the Package Junction-to-Ambient Thermal

Resistance, in °C/W,

– PD is the sum of PINT and PI/O,

– PINT is the product of IDD and VDD, expressed in

Watts. This is the Chip Internal Power

– PI/O represents the Power Dissipation on Input

and Output Pins; User Determined.

For most applications PI/O< PINT and may be ne-

glected. PI/O may be significant if the device is con-

figured to drive Darlington bases or sink LED Loads.

PD = K÷ (TJ + 273°C) (2)

Therefore:

K = PD x (TA + 273°C) + θJA x PD2 (3)

Where:

– K is a constant for the particular part, which may

be determined from equation (3) by measuring

PD (at equilibrium) for a known TA. Using this val-

ue of K, the values of PD and TJ may be obtained

by solving equations (1) and (2) iteratively for any

value of TA.

Table 25. Thermal Characteristics

Symbol

θJA

Package

SO34

PSDIP32

Typical Value

70

50

Unit

°C/W

(*): Maximum chip dissipation can directly be obtained from Tj (max), θJA and TA parameters.

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