TCA6408A: TCA6408A Power Sequence Issue

Minghui Zhang

Part Number: TCA6408A
Other Parts Discussed in Thread: TCAL6408

Hi there,

I've used TCA6408A before and the I2c bus will be stuck during high temp if VCCI is powered before VCCP, also TI has provided a new package to address this issue. May I know which package I should use to avoid this issue?

Thanks,
Minghui

over 2 years ago

0 Tyler Townsend over 2 years ago

TI__Guru 53208 points

Hi Minghui,

This is a known concern for the TCA6408A. We recommend that you switch the order of the power supplies by powering VCCP first, then VCCI. If you power VCCI first before VCCP, you risk the SDA bus getting stuck low. This issue should also resolve itself if you power both supplies at the same time.

I am not aware of this being a package specific issue, I believe all package types from TSSOP, VQFN, and UQFN all experience this issue.

Regards,

Tyler

0 Minghui Zhang over 2 years ago in reply to Tyler Townsend

Prodigy 30 points

Hi Tyler,

Thanks for sharing the information, as far as I know, TI has rev the die w/ some sort of package to address this issue. Can you please check it?

Thanks,
Minghui

0 Minghui Zhang over 2 years ago in reply to Minghui Zhang

Prodigy 30 points

Okay, I've digged the rabbit hole and figured out the new part is TCAL6408, the package is X2QFN, can you please confirm this part has addressed the power sequence requirement for the IO expander?

+1 Tyler Townsend over 2 years ago in reply to Minghui Zhang

TI__Guru 53208 points

Hi Minghui,

Yes you are correct. Our TCAL64xx family of parts fixed this issue.

Regards,

Tyler

0 Minghui Zhang over 2 years ago in reply to Tyler Townsend

Prodigy 30 points

Thank you Tyler to confirm it. As to the TCAL6408, it has three packages, and I have found two packages has order information, while datasheet has TSSOP package, which is really nice, coz it can be dropped in replacement for TCL6408. May I know the status of this package? Such as, are they released and in the production mode? If so, what's the lead time and part number to order this part?

PTCAL6408RSVR (not sure why it has P there) and TCAL6408DTUR

Thanks,
Minghui

+1 Tyler Townsend over 2 years ago in reply to Minghui Zhang

TI__Guru 53208 points

Hi Minghui,

Please message me offline as this information is sensitive on a public forum.

t-townsend@ti.com

Regards,

Tyler

0 Gilbert Lien over 2 years ago in reply to Tyler Townsend

TI__Intellectual 1060 points

Hi Tyler,

May I know where can I find the related information of TCAL64 family fixed this issue?

Thanks,

Gilbert.

0 Tyler Townsend over 2 years ago in reply to Gilbert Lien

TI__Guru 53208 points

Hi Gilbert,

I believe the information you are looking for is hidden in the design files for the power-on-reset circuitry. I don't have access to this information at the moment, and cannot share it on a public forum.

Please contact me here on my email if this request is urgent. Our design team is very busy at the moment, and the request may take a week or two to get you a correct answer.

t-townsend@ti.com

Regards,

Tyler

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TCA6408A: TCA6408A Power Sequence Issue

PTCAL6408RSVR (not sure why it has P there) and TCAL6408DTUR