TCA6408A: I2C line to Low state during RESET initialization

Hi Toshiro,

What exactly do you mean by the I2C line going low during RESET. Do you mean the device is already powered up and then you toggle reset and see SDA go low for a moment?

-Bobby

Hi Bobby,

Thank you very much for your quick reply.

We could not get our customer exact use case though, would it be possible to let us know following two cases.

1. Device is already powered up then toggle /RESET.

2. during Power up with /RESET=Low.

Best regards,

Hi Toshiro,

Toshiro Imi said:

1. Device is already powered up then toggle /RESET.

This should be fine, I've never heard of any issues with this situation occur before.

Toshiro Imi said:

2. during Power up with /RESET=Low.

This should also technically be okay.

There is one case that we've seen some troubles with. It doesn't have to do with the #RESET but instead the power sequencing of TCA64XX. I believe Vccp needs to power up before Vcci or in some cases the SDA can lock until both power supplies are up. I'll need to double check on the power sequence to be sure but we are planning to update the datasheet to state this in the power supply section as well as issue a PCN when the change is made. 

-Bobby

Hi Bobby,

Thank you very much. I understood.

Regarding to VCCI, VCCP power sequencing, would you let us know the secure way that will not happened SDA lock condition that are known at this moment.

best regards,