PCA9535: Theta-JA and Max Tj

Jessica Ballard

Part Number: PCA9535

What is the theta-ja and max junction temp?

In https://e2e.ti.com/support/interface-group/interface/f/interface-forum/798199/pca9535-tj-max?tisearch=e2e-sitesearch&keymatch=PCA9535# I believe this meant Tj max is 105C? But just below it they said max Tj is 85C.

over 3 years ago

0 Clemens Ladisch over 3 years ago

Guru 320720 points

Max Tj is 150 °C; see [FAQ] What is the maximum junction temperature (TJMAX) for a device?

0 Jessica Ballard over 3 years ago in reply to Clemens Ladisch

Prodigy 20 points

Thank you Clemens. Can you still provide the Theta-JA value?

0 BOBBY over 3 years ago in reply to Jessica Ballard

TI__Guru* 78461 points

There are two categories for Tj max: Absolute and recommended.

Recommended means if you stay below or at the threshold value provided (Tj recommended) then the device will meet the electrical parameters set in the datasheet.

Absolute means if you go above the recommended but stay below the absolute, the device may no longer meet electrical parameters set in the datasheet but the device will not break/be damaged. Going above the absolute will likely damage the device. FIT rate may also increase if you go above the recommended.

For the PCA (I2C state machine) devices, I generally state 105C for absolute and 85C for recommended. (these are low power devices so TA is slightly below TJ, I simplify it to being about equal for most cases)

Theta JA is provided in section 6.4 of the datasheet table labeled "Thermal Resistance Characteristics" and varies depending on the package.

-Bobby

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PCA9535: Theta-JA and Max Tj