TCA9539-Q1: TCA9539-Q1 about Fail-safe

Lawrence He

Part Number: TCA9539-Q1

Tool/software:

Hi, Support Team

if TCA9539-Q1 is failure and cannot offer ON/OFF(GPIO) to output, how to make sure the ic do not false action ?
do we have internal prevention mechanism.

if any suggestion, Please advise me.

Thanks,

Best regards,

Lawrence

9 months ago

0 Clemens Ladisch 9 months ago

Guru 299450 points

This device's state machine is controlled entirely with the I²C bus. It should not be possible for it to lock up.

Anyway, it can always be reset with the /RESET input.

When you exceed the absolute maximum ratings, the device might get damaged, and then there are no guarantees.

0 Tyler Townsend 9 months ago

TI__Mastermind 38263 points

Hi Lawrence,

I am trying to understand your question fully here.

TCA9539-Q1 can only change the GPIO state through the I2C bus. If the device fails to change GPIO, it is because of the I2C bus not working properly. The IO expander will retain its I/O configuration unless a power on reset occurs, a device reset (/RESET pin), or the registers are written with data from the I2C bus through proper I2C transactions.

Regards,

Tyler

0 Lawrence He 9 months ago in reply to Clemens Ladisch

Genius 3085 points

Hi, Clemens

here is our client function block as below chart:

if power 3.3v suddenly shunt down, I/O Expander(TCA9539-Q1) could possible have 1.2v output voltage to H side block?

if any suggestion, Please advise me.

Thanks,

Best regards,

Lawrence

0 Tyler Townsend 9 months ago in reply to Lawrence He

TI__Mastermind 38263 points

Hi Lawrence,

Please see this e2e.

https://e2e.ti.com/support/interface-group/interface---internal/f/interface---internal-forum/1324012/tca9539-q1-esd-protection-and-ov

I think it covers your question. I don't suspect back-biasing to occur through the IO when powered-down on VCC.

Regards,

Tyler

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TCA9539-Q1: TCA9539-Q1 about Fail-safe