TCA9800: Does the device work when the VCC comes later?

David Huang

Part Number: TCA9800

Hi team

For the application connecting VCCA and VCCB together, is it safe to power the IO first and then power up the VCC afterwards? Will this event cause latch-up?

(This event is because of the board setup and sequence power)

If this application does not work with TCA9800, is there any other recommendations?

Regards

David

over 4 years ago

0 Clemens Ladisch over 4 years ago

Guru 324370 points

This will work; see [FAQ] Can the input voltage (Vi) to my logic device be higher than the supply voltage (Vcc)?

0 Eric Schott1 over 4 years ago in reply to Clemens Ladisch

TI__Guru 53535 points

Thanks Clemens!

Hi David,

This conditions will not impact the startup capability of the device. I would also recommend reviewing section 9.3.5 of the datasheet for unpowered channel behavior to see impacts on any potential communication on these lines before Vcc powerup. See the document Clemens linked for possible system-level impacts of this power sequence (unlikely to be any issues in this case).

Let us know if you have any more questions.

Regards,
Eric Schott

Interface

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TCA9800: Does the device work when the VCC comes later?